Search

An early step of evaluating a nanomaterial’s potential for biological applications is investigating its interactions with cells and biological fluids. These experiments generate complex data, which...

Polymer nanocapsules, with a hollow structure, are increasingly finding widespread use as drug delivery carriers; however, quantitatively evaluating the bio-nano interactions of nanocapsules remains challenging. Herein, poly(ethylene glycol) (PEG)-based metal-phenolic network (MPN) nanocapsules of three sizes (50, 100, and 150 nm) are engineered via supramolecular template-assisted assembly and the effect of the nanocapsule size on bio-nano interactions is investigated using in vitro cell experiments, ex vivo whole blood assays, and in vivo rat models. To track the nanocapsules by mass cytometry, a preformed gold nanoparticle (14 nm) is encapsulated into each PEG-MPN nanocapsule. The results reveal that decreasing the size of the PEG-MPN nanocapsules from 150 to 50 nm leads to reduced association (up to 70%) with phagocytic blood cells in human blood and prolongs in vivo systemic exposure in rat models. The findings provide insights into MPN-based nanocapsules and represent a platform for studying bio-nano interactions.

When nanoparticles interact with human blood, a multitude of plasma components adsorb onto the surface of the nanoparticles, forming a biomolecular corona. Corona composition is known to be influenced by the chemical composition of nanoparticles. In contrast, the possible effects of variations in the human blood proteome between healthy individuals on the formation of the corona and its subsequent interactions with immune cells in blood are unknown. Herein, we prepared and examined a matrix of 11 particles (including organic and inorganic particles of three sizes and five surface chemistries) and plasma samples from 23 healthy donors to form donor-specific biomolecular coronas (personalized coronas) and investigated the impact of the personalized coronas on particle interactions with immune cells in human blood. Among the particles examined, poly(ethylene glycol) (PEG)-coated mesoporous silica (MS) particles, irrespective of particle size (800, 450, or 100 nm in diameter), displayed the widest range (up to 60-fold difference) of donor-dependent variance in immune cell association. In contrast, PEG particles (after MS core removal) of 860, 518, or 133 nm in diameter displayed consistent stealth behavior (negligible cell association), irrespective of plasma donor. For comparison, clinically relevant PEGylated doxorubicin-encapsulated liposomes (Doxil) (74 nm in diameter) showed significant variance in association with monocytes and B cells across all plasma donors studied. An in-depth proteomic analysis of each biomolecular corona studied was performed, and the results were compared against the nanoparticle-blood cell association results, with individual variance in the proteome driving differential association with specific immune cell types. We identified key immunoglobulin and complement proteins that explicitly enriched or depleted within the corona and which strongly correlated with the cell association pattern observed across the 23 donors. This study demonstrates how plasma variance in healthy individuals significantly influences the blood immune cell interactions of nanoparticles.

The kynurenine pathway of tryptophan metabolism has been implicated in brain function, immunoregulation, anti-microbial mechanisms and pregnancy. Some of these actions are due to depletion of tryptophan and others to the formation of biologically active metabolites. This review focuses on the roles of the kynurenine pathway in host responses during two parasitic diseases of major health and economic importance, malaria and toxoplasmosis, with an emphasis on their impacts on CNS function. This article is part of the Special Issue entitled ‘The Kynurenine Pathway in Health and Disease’.

Mass cytometry is a technique that uses inductively coupled plasma mass spectrometry (ICP-MS) to quantify the isotopic composition of cells in suspension. Traditionally it has been used in conjunction with antibodies labeled with stable lanthanide isotopes to investigate cellular heterogeneity. Here we describe its use to quantify uptake of metal nanoparticles by cells in suspension.

Quantification of cell-associated nanoparticles (NPs) is a paramount question in both nanomedicine and nanotoxicology. Inductively coupled plasma mass spectrometry is a well-established method to resolve cell-associated (metal) NPs in bulk cell populations, however, such analysis at single cell level remains a challenge. Here we used mass cytometry, a technique that combines single cell analysis and time-of-flight mass spectrometry, to quantitatively analyze extra- and intracellular silver (Ag) in individual Ag NP exposed human T-lymphocytes. The results revealed significant population heterogeneity: for example, in lymphocytes exposed to 3 μg of 30 nm branched polyethylene imine coated Ag NPs/mL the extracellularly bound Ag varied from 79 to 560 fg and cellular uptake from 17 to 121 fg. Similar amplitude of heterogeneity was observed in cells exposed to various doses of Ag NPs with other sizes and surface coatings, demonstrating the importance of single cell analysis when studying NP-cell interactions. Although mass cytometry has some shortcomings such as inability to analyze potential transformation or dissolution of NPs in cells, we consider this method as the most promising for quantitative assessment of cell-NP interaction at single cell level. Refereed/Peer-reviewed

Synthetic cannabinoids (SCs) have rapidly proliferated as recreational drugs, and may present a substantial health risk to vulnerable populations. However, information on possible effects of long-term use is sparse. This study compared acute and residual effects of the popular indazole carboxamide SC compounds AB-PINACA and AB-FUBINACA in adolescent rats with ∆9-tetrahydrocannabinol (THC) and control treatments. Albino Wistar rats were injected (i.p.) with AB-PINACA or AB-FUBINACA every second day (beginning post-natal day (PND) 31), first at a low dose (0.2 mg/kg on 6 days) followed by a higher dose (1 mg/kg on a further 6 days). THC-treated rats received equivalent doses of 6 × 1 mg/kg and 6 × 5 mg/kg. During drug treatment, THC, AB-PINACA, and AB-FUBINACA decreased locomotor activity at high and low doses, increased anxiety-like behaviours and audible vocalisations, and reduced weight gain. Two weeks after dosing was completed, all cannabinoid pre-treated rats exhibited object recognition memory deficits. These were notably more severe in rats pre-treated with AB-FUBINACA. However, social interaction was reduced in the THC pre-treated group only. Six weeks post-dosing, plasma levels of cytokines interleukin (IL)-1α and IL-12 were reduced by AB-FUBINACA pre-treatment, while cerebellar endocannabinoids were reduced by THC and AB-PINACA pre-treatment. The acute effects of AB-PINACA and AB-FUBINACA were broadly similar to those of THC, suggesting that acute SC toxicity in humans may be modulated by dose factors, including inadvertent overdose and product contamination. However, some lasting residual effects of these different cannabinoid receptor agonists were subtly different, hinting at recruitment of different mechanisms of neuroadaptation.

A study was conducted to compare the effects of two chemical therapeutants on channel catfish (CCF) Ictalurus punctatus concurrently infected with Flavobacterium columnare and Ichthyobodo necator. Copper sulfate (CuSO4) and potassium permanganate (KMnO4) were investigated for their ability to reduce the bacterial load, parasite load, and subsequent mortality. Treatment rates of CuSO4 or KMnO4 were 2.1 mg/L and 3.0 mg/L, respectively, and were applied at 24 h intervals on three consecutive days and control fish were untreated. Fin and gill samples were taken on day 4 (24 h after the final treatment) and day 10 (one week after the final treatment) for quantification of parasite and bacterial load. The survival rate of CuSO4-treated fish (73.0 %) was significantly different from the untreated control fish (41.5%). KMnO4-treated fish was (53.6%) and not significantly different from untreated control or CuSO4-treated fish. I. necator loads were significantly reduced by both CuSO4 and KMnO4, but only CuSO4 sign...

Peracetic acid (PAA) is a relatively new compound suggested for use to treat pathogens in aquaculture. It is approved for use in Europe, but not in the United States. This study determined the effectiveness of PAA for fungus control on channel catfish, Ictalurus punctatus (Rafinesque), eggs. The study consisted of five PAA concentrations (2.5, 5, 10, 15 and 20 mg L)1) and an untreated control in a flowthrough system. A single spawn was used for each replication (N = 4). Eggs were treated twice daily until the embryos developed eyes. When hatching was complete for all viable eggs, fry were counted to determine the percent survival in each treatment. Fungal growth was severe in the untreated controls resulting in 11% survival. Treatments of 2.5, 5 and 10 mg L)1 PAA were significantly different from the controls (P < 0.05). The highest percent survival of hatched fry was with 5 mg L)1 PAA administered twice daily; the 2.5 mg L)1 PAA treatment had slightly less survival, but gives a higher margin of safety in case of treatment error. Very little fungus was present in treatments receiving 2.5 mg L)1 PAA or higher, and concentrations of 15 and 20 mg L)1 PAA were toxic to the eggs. The mean survivals in the 0, 2.5, 5, 10, 15 and 20 mg L)1 PAA treatments were 11%, 60%, 63%, 62%, 32% and 0%, respectively. Therefore, PAA may be a compound that merits further investigations regarding its use in U.S. aquaculture.

Ichthyobodo necator is a single-celled biflagellate parasite, which in high density can cause significant mortality in young fish. Copper sulphate (CuSO4), potassium permanganate (KMnO4) and peracetic acid (PAA) were evaluated for effectiveness against ichthyobodosis. Treatments were: untreated control, 2.1 mg L−1CuSO4, 3.0 mg L−1 KMnO4, 1.5 mg L−1 PAA and 3.0 mg L−1 PAA, and were applied to flow-through tanks on three consecutive days. The study was designed to simulate the flow-through systems utilized in the commercial rearing of juvenile channel catfish (Ictalurus punctatus). Mortality was monitored daily to compare survival rate among treatments. Parasite intensity was assessed pre chemical exposure and 20–24 h after the third application to determine effectiveness of the treatment. An assessment was also done 7 days post application to investigate possible reoccurrence. Copper sulphate, KMnO4 and PAA (3.0 mg L−1) significantly reduced the infestation rate of I. necator. Copper sulphate significantly improved the survival of I. necator infested channel catfish after three flow-through applications compared with the untreated control. The 3.0 mg L−1 PAA resulted in significantly lower survival than the untreated control, the 1.5 mg L−1 PAA and the KMnO4 were not statistically different from the untreated control.

Aquaflor (florfenicol, 50% type A medicated article) is a relatively new antibiotic used in U.S. aquaculture and has been widely accepted as a safe and effective therapeutant. Some peer-reviewed studies have suggested that 15 mg florfenicol (FFC)·kg−1 body weight (BW)·d−1 for 10 d controls mortality to a greater extent than 10 mg FFC·kg−1 BW·d−1 for 10 d. This study evaluated the safety of Aquaflor to sunshine bass (female white bass Morone chrysops × male striped bass M. saxatilis) when administered in feed at 15 (1× the maximum proposed therapeutic dose), 45 (3×), and 75 (5×) mg FFC·kg−1 BW·d−1 for 20 d (2× the currently approved 10-d treatment duration). The medicated feed was top-coated with Aquaflor and fed at 2% BW·d−1 divided equally between the morning and afternoon feedings. Juvenile sunshine bass (13.6 ± 1.6 g [mean ± SD]) were stocked into 100-L flow-through tanks at 20 fish per tank. Diets were randomly assigned to three replicate tanks per treatment; fish in three additional nonstudy...

Ammonia concentrations in water can affect the severity of Flavobacterium columnare infections in fish. Two trials lasting 7 d each were conducted to determine the effect of a single immersion flush treatment of total ammonia nitrogen (TAN; 15 mg/L) on the survival of channel catfish Ictalurus punctatus infected with F. columnare; the chemical was added while the water flowed continuously through the tanks. Both trials consisted of four treatments: (1) no ammonia exposure and no bacterial challenge (control), (2) ammonia exposure only, (3) bacterial challenge only, and (4) both ammonia exposure and bacterial challenge. Two hours after exposure to ammonia, the highest un-ionized ammonia level was 0.43 mg/L. The percent un-ionized ammonia is based on TAN, temperature, and pH. Caudal fins from three fish in each treatment were sampled at 24 h posttreatment to be analyzed by quantitative real-time polymerase chain reaction (qPCR). No significant difference in survival (mean ± SE) was noted between th...

Reduced survival of fish eggs is often a result of infestation with fungi Saprolegnia spp. However, timely chemical treatments often limit these infestations and increase survival. The effect of copper sulfate pentahydrate (CSP; 10 mg of CSP/L of water), diquat bromide (25 mg of diquat cation/L), formalin (433 mg/L), and hydrogen peroxide (H2O2; 250 mg/L) on percent hatch and fungal infestation in eggs of channel catfish Ictalurus punctatus was compared in two identical trials (five replicates for each chemical treatment per trial). The percent hatch in all chemical treatments was significantly better than percent hatch of the controls. The amount of fungal coverage on egg masses treated with CSP, formalin, and H2O2 was significantly less than that observed on the controls. Although not statistically different from the other treatments, H2O2 at 250 mg/L exhibited the highest average percent hatch (64%; control hatch = 34%), the lowest fungal coverage (1.5 cm; control coverage = 7.2 cm), and the l...

The free-living infective theront of Ichthyophthirius multifiliis historically has been thought to be the only stage susceptible to treatment. Here we introduce a technique to determine the toxicity of compounds to the newly released tomont, the encysted tomont and the developing tomites within the tomont that emerge as theronts. The toxicity of Wofasteril E400 (40% peracetic acid, PAA) to free-living forms of I. multifiliis was determined shortly after tomonts were physically removed from the surface of the fish and at 2.5 and 24 h after removal. Results indicate that 0.6 to 0.9 mg l(-1) PAA killed 39 to 82% of the newly released tomonts within 48 h when treated immediately. In a second experiment, tomonts were allowed to settle for 2.5 h after sampling from the skin and then treated for 12 h; concentrations > or =0.5 mg l(-1) PAA produced significantly fewer theronts than the controls. In a third experiment, encysted tomonts that were exposed to PAA 24 h after sampling from the skin and treated for 2 or 4 h produced a variable amount of theronts, but the concentrations tested (0.5 to 3.0 mg l(-1)) did not halt theront production. This research demonstrates that encysted I. multifiliis are less susceptible to chemical treatments.

Fungal infestations of channel catfish Ictalurus punctatus eggs can lower hatch rate, which requires the producer to spawn more channel catfish or risk fingerling shortages. Hydrogen peroxide (H2O2) treatments (0.0, 15.6, 31.3, 62.5, 125, 250, 500, 1,000, 2,000, and 4,000 mg/L) were evaluated to determine their effect on channel catfish hatch rate (number of fry/number of eggs × 100) and control of naturally occurring infestations of fungi Saprolegnia spp. in an experimental compartmentalized trough hatching system. Experiments were run at water temperatures of 23.2–24.0°C, dissolved oxygen concentrations of 4.5–6.8 mg/L (53–79% saturation), total alkalinity of 209–217 mg/L, and total hardness of 91–110 mg/L. Treatments were applied to hatching compartments while well water was flowing at a rate of one water exchange every 30 min and egg density was 2.5 g eggs/L of water. Observations for fungal development were made daily, and the maximum measure of fungal growth was recorded. An initial range-f...

Ice-water and salt treatments were evaluated for disinfection of small immersible fisheries equipment contaminated with a nonindigenous tropical snail, the red-rim melania Melanoides tuberculatus. This introduced species can displace native snails and transmit trematodes directly to fish and indirectly to other animals, including humans. The red-rim melania has a well-developed operculum that protects it from desiccation and allows it to remain viable for days on dry fisheries equipment. Treatments were produced by adding 10 kg of salt and 33.3 kg of ice to 66.6 L of water (salt–ice-water [SIW]) or by adding 40 kg of ice to 32 L of water (ice-water only [IW]) and were tested for various periods (0.17 min to 24 h) to find exposures that would kill 100% of the treated snails. Temperatures produced in the test containers ranged from −6.3°C to −2.4°C for SIW and from 0°C to 4.9°C for IW. The survival of snails in saltwater-only (SW) treatments (10 kg of NaCl in 100 L of water) was also tested. Three ...

The biflagellated, single-celled parasite Ichthyobodo necator can cause significant losses among fish populations, particularly those cultured in tanks. Treatments of KMnO4 and CuSO4 were evaluated against a naturally occurring I. necator infestation on sunshine bass (female white bass Morone chrysops x male striped bass M. saxatilis) raised in tanks. Four-hour static treatments with 3 mg of KMnO4/L of water (2.5 mg/L above the determined KMnO4 demand) or 2 mg of CuSO4/L of water (total alkalinity = 207 mg/L; total hardness = 95 mg/L) were randomly applied to 4 tanks/treatment (23 fish/tank); the same treatments were reapplied 2 d later. Four tanks were used as positive controls. By 2 d posttreatment (after the second treatment), only 17.4% of the untreated control fish survived, and a sample of the remaining fish was heavily infested with I. necator. All remaining control fish were dead by 5 d posttreatment. The KMnO4 treatment significantly curtailed the initial mortality (survival = 92.4%) and slightly reduced the high parasite loads at 2 d posttreatment. However, fish mortalities increased dramatically over the next 3 d (survival at 5 d posttreatment = 37.5%), and parasite loads from sampled fish remained high. The CuSO4 treatment was effective in significantly lowering the parasite load (almost eliminating I. necator) and maintaining a high fish survival (87.5%) by 5 d posttreatment. The findings in this study clearly demonstrate that CuSO4 is a viable treatment for ichthyobodosis in tanks.

The faucet snail Bithynia tentaculata, a nonindigenous aquatic snail from Eurasia, was introduced into Lake Michigan in 1871 and has spread to the mid-Atlantic states, the Great Lakes region, Montana, and most recently, the Mississippi River. The faucet snail serves as intermediate host for several trematodes that have caused large-scale mortality among water birds, primarily in the Great Lakes region and Montana. It is important to limit the spread of the faucet snail; small fisheries equipment can serve as a method of snail distribution. Treatments with chemical disinfection, pH extremes, and heated water baths were tested to determine their effectiveness as a disinfectant for small fisheries equipment. Two treatments eliminated all test snails: (1) a 24-h exposure to Hydrothol 191 at a concentration of at least 20 mg/L and (2) a treatment with 50°C heated water for 1 min or longer. Faucet snails were highly resistant to ethanol, NaCl, formalin, Lysol, potassium permanganate, copper sulfate, Ba...

An experiment was performed to evaluate the in vitro and in vivo efficacy of potassium permanganate (KMnO4) against Flavobacterium columnare. In vitro, F. columnare treated with KMnO4 at 2 mg/L for 8 h exhibited a 70% reduction in colony-forming units (CFU). A minimum KMnO4 concentration of 10 mg/L was needed to inhibit bacterial growth. An acute and systemic experimental infection was produced in channel catfish Ictalurus punctatus by waterborne exposure to the bacteria after mechanical cutaneous abrasion to remove mucus and epithelium. At 22 h postchallenge, an 8-h treatment with KMnO4 at 2.3 mg/L (2.0 mg/L above the average KMnO4 demand of 0.3 mg/L) was initiated. This did not reduce mortality in experimentally infected fish. The infection model utilized in the experiment was evaluated by examining the clinical signs and histopathology of infected fish. Fish in the model showed columnaris signs similar to those of a natural infection, including skin depigmentation and ulceration and gill necro...

The proinflammatory cytokine interferon-gamma (IFNγ) recently was shown to play a crucial role in experimental pneumococcal meningitis (PM) pathogenesis, and we aimed in this study to investigate IFNγ-driven nitric oxide synthase-2 (NOS2)-mediated pathogenesis of murine PM. We demonstrate that costimulation of toll-like receptors and IFNγ receptors was synergistic for NOS2 expression in cultured murine microglia. Using an experimental PM model, wild-type mice treated with anti-IFNγ antibody, as well as IFNγ and NOS2 gene knockout (GKO) mice, were inoculated intracerebroventricularly with 10(3) colony-forming units of Streptococcus pneumoniae (WU2 strain). Mice were monitored daily during a 200-h disease course to assess survival rate and blood-brain barrier (BBB) permeability measured at 48 h. IFNγ deficiency was protective in PM, with an approximate 3-fold increase in survival rates in both antibody-treated and IFNγ GKO mice compared to controls (P

Zeolites purchased from aquaculture industry suppliers vary in their ability to remove ammonia, and little information is provided about their origin, type, and purity. To evaluate them, a simplified method for comparing their ammonia control properties was developed. Ammonia levels from water treated with five different zeolites were effectively measured and compared with two different inexpensive total ammonia nitrogen (TAN) test kits using the same procedure. I found that 10 g of a zeolite added to and stirred in an ammonia solution (0.1 g of ammonium sulfate dissolved in 1 L water) for 20 min produced TAN levels within the readable ranges for the Hach Model NI-8 and NI-SA ammonia nitrogen test kits; a 1:6 dilution of the ammonia test solution was made just before the TAN analysis. The TAN readings after the addition of the five zeolites ranged from 1.2 to 2.6 mg/L (multiplying by 7 to get actual TAN readings is not necessary to compare zeolites) for the Model NI-8 kit. The Model NI-SA kit gav...

Tests were run to determine whether any refinements were warranted in an established copper sulfate–citric acid pond shoreline treatment (Environmental Protection Agency registration number 1278–8) for aquatic marsh rams-horn snails Planorbella trivolvis. The treatments applied in these studies consisted of two levels (full and half) of copper sulfate (CuSO4; 589 and 294.5 g) with and without citric acid (CA; 58.9 and 0 g) that were delivered in a 2-m swath 10-m length of shoreline. In research ponds, shoreline treatments without CA were significantly more effective against the snails than the treatments with CA. The full CuSO4 treatment without CA was significantly more effective than the half treatment without CA at all temperatures tested below 35°C. There was a significant reduction in the effectiveness of the full treatment without CA at 17 ± 0.5°C (40% snail survival), while snail survival (average, 3.2%) in the trials run at 21.5, 23, 26, and 35°C was not significantly different from each ...

D. LLOYD, J.C. HARRIS, S. MAROULIS, A. MITCHELL, M.N. HUGHES, R.B. WADLEY AND M.R. EDWARDS. 2003. Aims: To investigate the antigiardial properties of the nitrosating agents: sodium nitrite, sodium nitroprusside andRoussin’s black salt.Methods and Results: Use of confocal laser scanning microscopy and flow cytometry indicated permeabilizationof the plasma membrane to the anionic fluorophore, DiBAC 4 (3) [bis(1,3-dibutylbarbituric acid) trimethine oxonol].Loss of plasma membrane electrochemical potential was accompanied by loss of regulated cellular volume control.Changes in ultrastructure revealed by electron microscopy and capacity for oxygen consumption, were alsoconsequences of nitrosative stress. Roussin’s black salt (RBS), active at micromolar concentrations was the mostpotent of the three agents tested.Conclusions: These multitargeted cytotoxic agents affected plasma membrane functions, inhibited cellularfunctions in Giardia intestinalis and led to loss of viability.Significance and Impact of the Study: Nitrosative damage, as an antigiardial strategy, may have implications fordevelopment of chemotherapy along with suggesting natural host defence mechanisms.Keywords: flow cytometry, nitric oxide, nitrite, nitroprusside, nitrosonium cations, plasma membrane potential.

Largemouth bass Micropterus salmoides are piscivorous fish raised on farms then sold live in Asian fish markets on the east and west coasts of the United States. In the winter of 1998, a major producer of feed-trained bass suffered a significant increase in fish mortality both during shipping and while the fish were still in ponds. No bacterial, viral, or significant parasitic pathogens were found at necropsy. Livers of affected fish were pale and translucent with 3–10 mm pink nodules on their surface and deeper in the parenchyma. Histological examination of these livers showed that the translucent regions of the liver contained few hepatocytes and were composed of tissue consistent with a chronic inflammatory response. Also present were eosinophils, islands of pancreatic and biliary cells, and granulomas that did not stain positively for mycobacteria. The pink nodules were areas of multifocal regeneration of normal hepatocytes. Sequential studies of bass in ponds revealed that the bass were progressively accumulating glycogen in their hepatocytes to an extent sufficient to explain the massive necrosis of that organ. In order to determine the effect of diets varying in available carbohydrate on fish growth, survival, and liver glycogen content, a 12-wk feeding trial was conducted in aquaria with juvenile largemouth bass. Nitrogen-free extract values indicated that an extruded trout diet, a steelhead trout diet, and a diet designed to contain 45% protein and 25% fat, contained 35, 27, and 21% carbohydrate, respectively. Weight gain was lowest in fish fed the extruded trout diet, while liver glycogen was significantly higher in fish fed diets with >27% carbohydrate than in fish fed the diet with 21% carbohydrate. The farmer switched to a diet similar to the 45–25 diet used in our trial. Subsequently, 16-mo-old fish examined in October 2000 had no hepatic nodules or necrosis, were significantly larger and less variable in size than previous crops, and the farmer experienced no significant losses in ponds or during shipping.

The rams-horn snail Planorbella trivolvis carries at least two important digenetic trematodes that infect propagated fish species in the southeastern United States. These snails are found in fish production ponds, and there are no proven chemical methods for eliminating them that would not also kill the fish. Application of an aqueous solution of 589 g of copper sulfate and 58.9 g of citric acid per 10 linear meters in a 2-m-wide swath along the pond shoreline produced an effective treatment. This would give an instantaneous treatment rate of about 59 ppm if the water in the 2-m swath averaged 0.5 m deep. In two separate trials, there was a significant difference in snail survival in the treated and sham-treated ponds. Average survival was 2.2% and 0% in the treatment ponds and 63.3% and 77.8% in the sham treatment ponds.

A histological and hematological study was performed to evaluate the effect of waterborne exposures of channel catfish Ictalurus punctatus to potassium permanganate (KMnO4). Three concentrations of KMnO4 were chosen to represent one, three, and five times the therapeutic concentrations (0.438, 1.315, and 2.190 mg/L, respectively), based on the KMnO4 demand, for 36 h, which is three times the usual treatment duration. The organs examined were the gill, liver, and trunk kidney. Differential leukocyte counts of neutrophils and monocytes in the blood and plasma enzyme analyses (lactate dehydrogenase and alanine transaminase) were also performed. The gill was the only organ to show microscopic lesions. Fish exposed to the therapeutic concentration of KMnO4 for 36 h had mild hypertrophy and spongiosis in the gills sampled during exposure, but no lesions were noticed 2 d postexposure. Gills of fish exposed to three and five times the therapeutic dose had extensive hyperplasia, epithelial hypertrophy and...

Mast-cell degranulation is triggered by the bridging of Fc receptor-bound antigen-specific immunoglobulin IgE on the cell surface. In vitro experiments suggest that antibody affinity and nonspecific IgE may affect the mast-cell function, however, their importance in vivo is unclear. Investigations of the effects of these parameters on mast-cell sensitization were therefore carried out in a rat immunization model in which the IgE response is transient and peaks on days 10-15. Between these two timepoints, significant changes in the level of specific IgE were not observed, but the avidity of specific IgE increased (P < 0.05). Total serum IgE peaked on day 10 and slowly declined, with the relative proportion of specific to total IgE increasing from day 10-15 (P < 0.05). Despite similar levels of antigen-specific IgE, increasing avidity and an increased proportion of specific IgE between days 10 and 15, the biological activity of IgE in the serum peaks on day 10 and declines rapidly, dropping around seven-fold by day 15 (P < 0.001). Mechanisms that could explain this finding, such as differential expression of IgE isoforms and changes in the fine specificity of the IgE response, are discussed.

Therapeutic nanoparticles hold clinical promise for cancer treatment by avoiding limitations of conventional pharmaceuticals. Herein, a facile and rapid method is introduced to assemble poly(ethylene glycol) (PEG)-modified Pt prodrug nanocomplexes through metal-polyphenol complexation and combined with emulsification, which results in ≈100 nm diameter nanoparticles (PtP NPs) that exhibit high drug loading (0.15 fg Pt per nanoparticle) and low fouling properties. The PtP NPs are characterized for potential use as cancer therapeutics. Mass cytometry is used to quantify uptake of the nanoparticles and the drug concentration in individual cells in vitro. The PtP NPs have long circulation times, with an elimination half-life of ≈18 h in healthy mice. The in vivo antitumor activity of the PtP NPs is systematically investigated in a human prostate cancer xenograft mouse model. Mice treated with the PtP NPs demonstrate four times better inhibition of tumor growth than either free prodrug or cisplatin. This study presents a promising strategy to prepare therapeutic nanoparticles for biomedical applications.

BACKGROUND For many years the central focus of research into gastrointestinal hypersensitivity reactions has been the mast cell population of the intestinal lamina propria. Since bile is known to deliver immunological mediators to the gastrointestinal tract, the possibility arises that extra-intestinal populations of mast cells may also contribute to IgE-mediated intestinal damage. OBJECTIVES To characterize hepatic mast cells in the rat and to investigate the role of the hepatobiliary system in a model of IgE-mediated reactivity to dietary antigen. METHODS Wistar rats were passively sensitized with monoclonal antidinitrophenyl (DNP) IgE antibodies, and were later challenged orogastrically with DNP-HSA. Additional animals were sensitized, then bile duct-cannulated prior to antigen challenge. At various time points, liver and intestinal samples were collected for histological examination, and bile was collected and assayed for histamine and TNFalpha. RESULTS Hepatic mast cells display a mucosal mast cell-like phenotype, and are closely associated with the vessels of the portal triads. Orogastric antigen challenge led to a rapid and significant decline (P

We investigated the relationship between gut health, visceral fat dysfunction and metabolic disorders in diet-induced obesity. C57BL/6J mice were fed control or high saturated fat diet (HFD). Circulating glucose, insulin and inflammatory markers were measured. Proximal colon barrier function was assessed by measuring transepithelial resistance and mRNA expression of tight-junction proteins. Gut microbiota profile was determined by 16S rDNA pyrosequencing. Tumor necrosis factor (TNF)-α and interleukin (IL)-6 mRNA levels were measured in proximal colon, adipose tissue and liver using RT-qPCR. Adipose macrophage infiltration (F4/80+) was assessed using immunohistochemical staining. HFD mice had a higher insulin/glucose ratio (P = 0.020) and serum levels of serum amyloid A3 (131%; P = 0.008) but reduced circulating adiponectin (64%; P = 0.011). In proximal colon of HFD mice compared to mice fed the control diet, transepithelial resistance and mRNA expression of zona occludens 1 were reduced by 38% (P

Background Group 2 innate lymphoid cells (ILC2) have been implicated in the pathogenesis of allergic lung diseases. However, the upstream signals that regulate ILC2 function during pulmonary inflammation remain poorly understood. ILC2s have been shown to respond to exogenous IL-2, but the importance of endogenous IL-2 in ILC2 function in vivo remains unclear. Objective We sought to understand the role of IL-2 in the regulation of ILC2 function in the lung. Methods We used histology, flow cytometry, immunohistochemistry, ELISA, and quantitative PCR with knockout and reporter mice to dissect pulmonary ILC2 function in vivo . We examined the role of ILC2s in eosinophilic crystalline pneumonia, an idiopathic type 2 inflammatory lung condition of mice, and the effect of IL-2 deficiency on this disease. We determined the effect of IL-2 administration on pulmonary ILC2 numbers and function in mice in the steady state and after challenge with IL-33. Results We discovered an unexpected role for innate cell–derived IL-2 as a major cofactor of ILC2 function during pulmonary inflammation. Specifically, we found that IL-2 was essential for the development of eosinophilic crystalline pneumonia, a type 2 disease characterized by increased numbers of activated ILC2s. We show that IL-2 signaling serves 2 distinct functions in lung ILC2s, namely promoting cell survival/proliferation and serving as a cofactor for the production of type 2 cytokines. We further demonstrate that group 3 innate lymphoid cells are an innate immune source of IL-2 in the lung. Conclusion Innate cell–derived IL-2 is a critical cofactor in regulating ILC2 function in pulmonary type 2 pathology.

The efficacy of potassium permanganate (KMnO4) against the early stages of an experimental acute infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus, was evaluated. Fish were experimentally challenged by waterborne exposure for 2 h to F. columnare after cutaneous abrasion, and treated with KMnO4 at 2.0 mg L−1 above the KMnO4 demand at 0, 1, 2 or 4 h postchallenge for 24 h. Challenged non-treated fish acted as a positive control and non-challenged non-treated fish acted as a negative control. Fish challenged and treated with KMnO4 at 0, 1, 2 or 4 h postchallenge had mortalities of 26%, 63%, 64% and 83% respectively. The mortality of challenged fish treated with KMnO4 at 0 h postchallenge (26%) was significantly less than the positive control (77%). The mortalities of challenged fish treated at 1, 2 or 4 h postchallenge were not significantly different from the positive control fish. The results suggest that KMnO4 has a clear therapeutic value in early stages of columnaris infection but limited therapeutic value once the infection has progressed.

A trial was performed to evaluate the efficacy of diquat (6,7-dihydrodipyrido[1,2-a:2',1'-c]pyrazinediium dibromide) against an acute experimental infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus. Diquat is an Environmental Protection Agency-approved herbicide and has the potential to be legally and practically used against columnaris. Channel catfish were challenged, by cutaneous abrasion, and waterborne exposure to F. columnare and treated once at 22-h post-challenge with 2.5, 5.0, 10.0 and 15 mg L(-1) of diquat active ingredient for 6 h. At the conclusion of the trial, 21-day post-challenge, diquat at 5.0, 10.0 and 15 mg L(-1) significantly (P0.05) reduced the mortality of infected fish from 95% in the challenged non-treated fish to 68%, 59% and 49%, respectively. In vitro, the minimum inhibitory concentration (MIC) of 23 isolates of F. columnare was assayed. The majority of the isolates had an MIC value of 5 microg mL(-1) (15 of the 23 isolates). Infected fish exhibited acute clinical signs similar to a natural infection. The skin had severe ulcerative necrotizing dermatitis and the muscles had severe necrotizing myositis. The gills had severe multifocal necrotizing branchitis. The results demonstrate that diquat would reduce mortalities caused by an acute columnaris infection.

An experiment was performed to evaluate the efficacy of potassium permanganate (KMnO4) as a prophylactic and therapeutic treatment of an experimental subacute infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus. Fish were cutaneously abraded and divided into five treatment groups: (i) challenged by waterborne exposure to F. columnare and not treated with KMnO4 (positive control), (ii) challenged and simultaneously treated with KMnO4, (iii) challenged and treated with KMnO4 at 1, 6 and 9 days post-challenge, (iv) not challenged and treated with KMnO4 at 1, 6 and 9 days post-challenge (first negative control) and (v) not challenged and not treated (second negative control). The dosing of KMnO4 was 2.0 mg L(-1) above the potassium permanganate demand for 2 h duration. The survival of the group challenged and simultaneously treated with KMnO4 (99%) was significantly higher than the positive control (78%) and was not significantly different from the negative control groups. The challenged fish treated with KMnO4 post-challenge had 7% higher survival than the positive control (85% compared with 78%), but that difference was not statistically significant. The results demonstrate that KMnO4 has a clear prophylactic value but probably a marginal therapeutic value once the infection has established.

Channel catfish, Ictalurus punctatus (Rafinesque), with or without a preliminary 24 h exposure to 2 mg copper sulphate L(-1), were challenged with 7.5 x 10(6) colony forming units L(-1) of Edwardsiella ictaluri to determine the effect of copper sulphate on disease resistance. Catfish previously exposed to copper sulphate were significantly more resistant to the bacterial challenge than those not exposed. Catfish not exposed to copper sulphate suffered 35.5% mortality while catfish exposed to copper sulphate experienced 14.1% mortality. Copper concentrations were the same in tank waters of both exposed and control fish at the time of challenge, eliminating the possibility that copper in the water may have been toxic to bacteria. Copper concentrations in freeze dried and ground tissues of unexposed, exposed, and purged channel catfish were highest in fish before copper sulphate exposures suggesting that elevated tissue levels of copper were not responsible for the increased resistance to bacterial challenge. Competition for sites of bacterial attachment to gill or epithelial cells may account for the reduction in mortality; although this is not supported by the low copper content of fish tissue after copper exposure.

Production of reactive oxygen species by redox cycling in the presence of low levels of oxygen has been studied as a possible approach to anti-protozoal chemotherapeutic strategy. Incubation of the diplomonad flagellateGiardia intestinaliswith 2-methy-1,4-naphthoquinone (menadione), under anaerobic conditions, gave UV absorption changes characteristic of reduction to menadiol; partial reversal was observed on admitting O2. Under microaerobic conditions, similar to those on the surface of the jejunal mucosa, trophozoites consumed O2rapidly in the presence of menadione; reaction products included singlet O2(monitored by single photon counting of O2-dependent low-level chemiluminescence) and H2O2(measured by the formation of Complex I of microperoxidase). Trophozoites became swollen and incapable of regulatory volume control; these irreversible responses led to loss of motility, cessation of flagellar activity and cell death. Comparison of the sensitivities of trophozoites to metronidazole and menadione gave LC50values (μg ml−1) of 1·2 and 0·7, respectively; corresponding values for cysts (measured byin vitroexcystation capacities) were >50 and 1·3. Menadione (LD50in mice, 0·5 g kg−1) is therefore a potentially more useful and general anti-giardial agent than metronidazole, as it is active against cysts as well as trophozoites.

Substance P (SP) is a prototypical neuropeptide with roles in pain and inflammation. Numerous mechanisms regulate endogenous SP levels, including the differential expression of SP mRNA and the controlled secretion of SP from neurons. Proteolysis has long been suspected to regulate extracellular SP concentrations but data in support of this hypothesis is scarce. Here, we provide evidence that proteolysis controls SP levels in the spinal cord. Using peptidomics to detect and quantify endogenous SP fragments, we identify the primary SP cleavage site as the C-terminal side of the ninth residue of SP. If blocking this pathway increases SP levels, then proteolysis controls SP concentration. We performed a targeted chemical screen using spinal cord lysates as a proxy for the endogenous metabolic environment and identified GM6001 (galardin, ilomastat) as a potent inhibitor of the SP(1-9)-producing activity present in the tissue. Administration of GM6001 to mice results in a greater-than-three-fold increase in the spinal cord levels of SP, which validates the hypothesis that proteolysis controls physiological SP levels.