Ambient base-free glycerol oxidation over bimetallic PdFe/SiO2 by in situ generated active oxygen species

Low temperature oxidation of alcohols over heterogeneous catalysts is exceptionally challenging, particularly under neutral conditions. Herein, we report on an efficient, base-free method to oxidise glycerol over a 0.5%Pd-0.5%Fe/SiO2 catalyst at ambient temperature in the presence of gaseous H2 and O2. The exceptional catalytic performance was attributed to the in situ formation of highly reactive surface-bound oxygenated species, which promote the dehydrogenation on the alcohol. The PdFe bimetallic catalyst was determined to be significantly more active than corresponding monometallic analogues, highlighting the important role both metals have in this oxidative transformation. Fe leaching was confirmed to occur over the course of the reaction but sequestering experiments, involving the addition of bare carbon to the reactions, confirmed that the reaction was predominantly heterogeneous in nature. Investigations with electron paramagnetic resonance spectroscopy suggested that the reactivity in the early stages was mediated by surface-bound reactive oxygen species; no homogeneous radical species were observed in solution. This theory was further evidenced by a direct H2O2 synthesis study, which confirmed that the presence of Fe in the bimetallic catalyst neither improved the synthesis of H2O2 nor promoted its decomposition over the PdFe/SiO2 catalyst.

Correction to: Solvent Free Synthesis of PdZn/TiO2 Catalysts for the Hydrogenation of CO2 to Methanol

The article Solvent Free Synthesis of PdZn/TiO2 Catalysts for the Hydrogenation of CO2 to Methanol by Hasliza Bahruji, Jonathan Ruiz Esquius, Michael Bowker, Graham Hutchings, Robert D. Armstrong, Wilm Jones was originally published Online First without open access. After publication in volume 61, issue 3–4, pages 144–153, the author decided to opt for Open Choice and to make the article an open access publication. Therefore, the copyright of the article has been changed to ©The Author(s) 2018 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Platinum Nanoparticle Inclusion into a Carbonized Polymer of Intrinsic Microporosity: Electrochemical Characteristics of a Catalyst for Electroless Hydrogen Peroxide Production

The one-step vacuum carbonization synthesis of a platinum nano-catalyst embedded in a microporous heterocarbon (Pt@cPIM) is demonstrated. A nitrogen-rich polymer of an intrinsic microporosity (PIM) precursor is impregnated with PtCl₆2- to give (after vacuum carbonization at 700 °C) a nitrogen-containing heterocarbon with embedded Pt nanoparticles of typically 1⁻4 nm diameter (with some particles up to 20 nm diameter). The Brunauer-Emmett-Teller (BET) surface area of this hybrid material is 518 m² g-1 (with a cumulative pore volume of 1.1 cm³ g-1) consistent with the surface area of the corresponding platinum-free heterocarbon. In electrochemical experiments, the heterocarbon-embedded nano-platinum is observed as reactive towards hydrogen oxidation, but essentially non-reactive towards bigger molecules during methanol oxidation or during oxygen reduction. Therefore, oxygen reduction under electrochemical conditions is suggested to occur mainly via a 2-electron pathway on the outer carbon shell to give H₂O₂. Kinetic selectivity is confirmed in exploratory catalysis experiments in the presence of H₂ gas (which is oxidized on Pt) and O₂ gas (which is reduced on the heterocarbon surface) to result in the direct formation of H₂O₂.

The preparation of large surface area lanthanum based perovskite supports for AuPt nanoparticles: tuning the glycerol oxidation reaction pathway by switching the perovskite B site

Gold and gold alloys, in the form of supported nanoparticles, have been shown over the last three decades to be highly effective oxidation catalysts. Mixed metal oxide perovskites, with their high structural tolerance, are ideal for investigating how changes in the chemical composition of supports affect the catalysts' properties, while retaining similar surface areas, morphologies and metal co-ordinations. However, a significant disadvantage of using perovskites as supports is their high crystallinity and small surface area. We report the use of a supercritical carbon dioxide anti-solvent precipitation methodology to prepare large surface area lanthanum based perovskites, making the deposition of 1 wt% AuPt nanoparticles feasible. These catalysts were used for the selective oxidation of glycerol. By changing the elemental composition of the perovskite B site, we dramatically altered the reaction pathway between a sequential oxidation route to glyceric or tartronic acid and a dehydration reaction pathway to lactic acid. Selectivity profiles were correlated to reported oxygen adsorption capacities of the perovskite supports and also to changes in the AuPt nanoparticle morphologies. Extended time on line analysis using the best oxidation catalyst (AuPt/LaMnO₃) produced an exceptionally high tartronic acid yield. LaMnO₃ produced from alternative preparation methods was found to have lower activities, but gave comparable selectivity profiles to that produced using the supercritical carbon dioxide anti-solvent precipitation methodology.

Solvent Free Synthesis of PdZn/TiO2 Catalysts for the Hydrogenation of CO2 to Methanol

Catalytic upgrading of CO₂ to value-added chemicals is an important challenge within the chemical sciences. Of particular interest are catalysts which are both active and selective for the hydrogenation of CO₂ to methanol. PdZn alloy nanoparticles supported on TiO₂ via a solvent-free chemical vapour impregnation method are shown to be effective for this reaction. This synthesis technique is shown to minimise surface contaminants, which are detrimental to catalyst activity. The effect of reductive heat treatments on both structural properties of PdZn/TiO₂ catalysts and rates of catalytic CO₂ hydrogenation are investigated. PdZn nanoparticles formed upon reduction showed high stability towards particle sintering at high reduction temperature with average diameter of 3–6 nm to give 1710 mmol kg⁻¹ h of methanol. Reductive treatment at high temperature results in the formation of ZnTiO₃ as well as PdZn, and gives the highest methanol yield.

How to Synthesise High Purity, Crystalline d-Glucaric Acid Selectively

Glucaric acid has potential applications in food, pharmaceutical and polymer industries yet no methodology exists within the public domain for isolation of this key bio-derived platform molecule as a pure, crystalline solid. Here we demonstrate the difficulties, which arise in doing so and report development of a process for derivation of free-glucaric acid from its Ca²⁺/K⁺ glucarate salts, which are both commercially available. Employing Amberlyst-15 (H⁺) exchange resin and azeotrope drying, powdered glucaric acid is prepared at > 99.96 % purity in 98.7 % dry yield.

Base-free oxidation of glucose to gluconic acid using supported gold catalysts

1% Au/TiO₂ catalysts prepared by a variety of methods were studied for the base-free oxidation of glucose.

The partial oxidation of propane under mild aqueous conditions with H2O2 and ZSM-5 catalysts

We report the oxidation of propane under mild aqueous conditions using H₂O₂ as the oxidant.

The selective oxidation of n-butanol to butyraldehyde by oxygen using stable Pt-based nanoparticulate catalysts: an efficient route for upgrading aqueous biobutanol

Supported Pt nanoparticles are shown to be active and selective towards butyraldehyde in the base-free oxidation of n-butanol by O₂ in an aqueous phase.

Low temperature selective oxidation of methane to methanol using titania supported gold palladium copper catalysts

Selective oxidation of methane using AuPdCu/TiO₂ catalysts.

Flea (Ctenocephalides felis) control efficacy of topical indoxacarb on dogs subsequently bathed with a chlorhexidine-ketoconazole shampoo

OBJECTIVE

An evaluation of the effect of chlorhexidine/ketoconazole shampoo baths on the flea control efficacy of indoxacarb applied topically to dogs.

METHODS AND RESULTS

We randomly allocated 18 healthy mixed-breed dogs to 3 groups: shampoo only; indoxacarb treated and medicated shampoo; and indoxacarb treated but not shampooed. Indoxacarb was administered on day 0 and dogs were shampooed on days 9 and 23. Dogs were infested with 100 adult Ctenocephalides felis initially 2 days before treatment and then weekly from days 7 to 28. Fleas were removed and counted 48 h post-infestation.

CONCLUSION

Medicated shampoo use did not significantly reduce indoxacarb efficacy against C. felis.

Light alkane oxidation using catalysts prepared by chemical vapour impregnation: tuning alcohol selectivity through catalyst pre-treatment

Heat treating Fe/ZSM-5 under hydrogen leads to high dispersion of Fe species and higher alcohol selectivity in the oxidation of alkanes, as compared to oxygen treated catalysts.

Partial oxidation of ethane to oxygenates using Fe- and Cu-containing ZSM-5

Iron and copper containing ZSM-5 catalysts are effective for the partial oxidation of ethane with hydrogen peroxide giving combined oxygenate selectivities and productivities of up to 95.2% and 65 mol kgcat(-1) h(-1), respectively. High conversion of ethane (ca. 56%) to acetic acid (ca. 70% selectivity) can be observed. Detailed studies of this catalytic system reveal a complex reaction network in which the oxidation of ethane gives a range of C2 oxygenates, with sequential C-C bond cleavage generating C1 products. We demonstrate that ethene is also formed and can be subsequently oxidized. Ethanol can be directly produced from ethane, and does not originate from the decomposition of its corresponding alkylperoxy species, ethyl hydroperoxide. In contrast to our previously proposed mechanism for methane oxidation over similar zeolite catalysts, the mechanism of ethane oxidation involves carbon-based radicals, which lead to the high conversions we observe.

Pharmacokinetic-pharmacodynamic integration of orbifloxacin in Japanese quail (Coturnix japonica) following oral and intravenous administration

The pharmacokinetics of single-dose administration of orbifloxacin were determined in Japanese quail (Coturnix japonica) at dosages of 5 mg/kg intravenous (i.v. n = 12) and 7.5 mg/kg oral (p.o.; n = 5), 10 mg/kg p.o. (n = 5), 15 mg/kg p.o. (n = 12) and 20 mg/kg p.o. (n = 5) via HPLC. Orbifloxacin minimal inhibitory concentrations (MICs) against 22 microbial isolates from various bird species were performed to calculate pharmacodynamic surrogate markers. The concentration-time data were analyzed using a naïve pooled data (NPD) approach and compartmental and noncompartmental methods. Steady-state volume of distribution (Vd(ss)) and total body clearance (Cl) after i.v. administration were estimated to be 1.27 L/kg and 0.60 L/h·kg, respectively. Following 15 and 20 mg/kg p.o. dose, bioavailability was 102% and 117%, respectively. The harmonic mean of the corresponding terminal half-lives (T(1/2) λ(z) ) across all the dose groups was 1.71 h. The C(max) /MIC(90) and AUC(0∞24) /MIC(90) for the 15 and 20 mg/kg p.o. doses were ≥5.22 and ≥8.98, and ≥25.80 and ≥39.37 h, respectively. The results of this study suggest that 20 mg/kg orbifloxacin p.o. would be a rational daily dose to treat susceptible infections in Japanese quail not intended for food consumption. For more sensitive bacterial organisms, 15 mg/kg p.o. may also be effective.

Comparative adrenocortical suppression in dogs with otitis externa following topical otic administration of four different glucocorticoid-containing medications

The safety of using otic formulations is often of concern for practitioners and pet owners alike, with "safe" in this context meaning no adrenocortical suppression. This study evaluated the effect of four glucocorticoid-containing otic formulations on plasma cortisol concentrations, measured by corticotropin stimulation testing (plasma cortisol concentrations before and after corticotropin injection), in dogs presented with otitis externa. Dexamethasone tended to have larger adrenocortical suppression compared with the other three formulations (betamethasone, triamcinolone, and mometasone), but the difference was not statistically significant. The largest difference among the four drugs was observed between dexamethasone and betamethasone (P=.09).

A phase II trial evaluating the safety and effectiveness of the AastromReplicell system for augmentation of low-dose blood stem cell transplantation

To reduce the number of apheresis procedures and maintain the usual rate of hematopoietic recovery in patients treated with high-dose chemotherapy, we studied the effect of adding a small volume of ex vivo expanded bone marrow to low doses of CD34(+) blood stem cells. Thirty-four patients with breast cancer received G-CSF (10 microg/kg/day) priming followed by a limited volume (50-100 ml) bone marrow aspiration and standard 10-liter aphereses. Marrow was expanded ex vivo using the AastromReplicell system and infused along with low doses of blood-derived CD34(+) cells, collected in one apheresis. Thirty-one evaluable patients received a median CD34(+) blood stem cell dose of 0.7 x 10(6)/kg (range, 0.2-2.5) and 4.7 x 10(7) nucleated cells/kg (range, 1.98-8.7) of ex vivo expanded marrow. All patients recovered with normal blood counts and engrafted 500 neutrophils/microl and 20 000 platelets/microl in a median of 10 and 13 days, respectively. Multivariate analysis revealed that, in addition to CD34(+) lineage negative cell quantity, the quantity of stromal progenitors contained in the ex vivo expanded product correlated with engraftment outcome (r = 0.551, P = 0.004). Our results indicate that ex vivo expanded bone marrow is capable of facilitating engraftment when combined with low doses of mobilized blood derived CD34(+) cells.

Prompt and durable engraftment in two older adult patients with high risk chronic myelogenous leukemia (CML) using ex vivo expanded and unmanipulated unrelated umbilical cord blood

Delayed engraftment, graft failure, and adverse transplant-related events have been observed in unrelated umbilical cord blood (UCB) recipients, particularly in those receiving a low leukocyte cell dose and in CML patients. We report the outcomes of two older adult patients with high risk CML who received a low leukocyte cell dose of unmanipulated UCB cells supplemented with ex vivo expanded (AastromReplicell System) UCB cells. Each engrafted promptly and neither patient experienced GVHD or life-threatening infection. Both remain engrafted with cells exclusively of donor origin and are in cytogenetic remission at 19 and 8 months follow-up. Ex vivo expanded UCB cells appear to facilitate hematopoietic recovery and therefore may increase the number of CML patients eligible for unrelated UCB transplant.

Autologous transplantation of ex vivo expanded bone marrow cells grown from small aliquots after high-dose chemotherapy for breast cancer

The collection of small aliquots of bone marrow (BM), followed by ex vivo expansion for autologous transplantation may be less morbid, and more cost-effective, than typical BM or blood stem cell harvesting. Passive elimination of contaminating tumor cells during expansion could reduce reinoculation risks. Nineteen breast cancer patients underwent autotransplants exclusively using ex vivo expanded small aliquot BM cells (900-1200 x 10(6)). BM was expanded in media containing recombinant flt3 ligand, erythropoietin, and PIXY321, using stromal-based perfusion bioreactors for 12 days, and infused after high-dose chemotherapy. Correlations between cell dose and engraftment times were determined, and immunocytochemical tumor cell assays were performed before and after expansion. The median volume of BM expanded was 36.7 mL (range 15.8-87.0). Engraftment of neutrophils greater than 500/microL and platelets greater than 20,000/microL were 16 (13-24) and 24 (19-45) days, respectively; 1 patient had delayed platelet engraftment, even after infusion of back-up BM. Hematopoiesis is maintained at 24 months, despite posttransplant radiotherapy in 18 of the 19 patients. Transplanted CD34(+)/Lin(-) (lineage negative) cell dose correlated with neutrophil and platelet engraftment, with patients receiving greater than 2.0 x 10(5) CD34(+)/Lin(-) cells per kilogram, engrafting by day 28. Tumor cells were observed in 1 of the 19 patients before expansion, and in none of the 19 patients after expansion. It is feasible to perform autotransplants solely with BM cells grown ex vivo in perfusion bioreactors from a small aliquot. Engraftment times are similar to those of a typical 1000 to 1500 mL BM autotransplant. If verified, this procedure could reduce the risk of tumor cell reinoculation with autotransplants and may be valuable in settings in which small stem cell doses are available, eg, cord blood transplants. (Blood. 2000;95:2169-2174)

Electrochemical sensor for measurement of urea and creatinine in serum based on ac impedance measurement of enzyme-catalyzed polymer transformation

Enzyme-catalyzed polymer transformation with electrochemical ac impedance detection has been employed for the measurement of urea and creatinine in serum samples. A polymer, based on poly(methylvinyl ether)/maleic anhydride modified by esterification with n-octanol, which is stable at pH 7.4 and which is transformed rapidly in response to alkaline pH changes, was linked to enzymatic reactions between urease and urea or creatinine deiminase and creatinine to produce a disposable sensor system. The polymer was screen-printed onto interdigitated screen-printed carbon electrodes and the electrodes overlaid with absorbent pads containing the relevant enzyme. Application of serum samples, "spiked" with either urea or creatinine, resulted in rapid polymer transformation, and resultant changes in the capacitance of the polymer-coated electrodes were analyte-concentration dependent. Additional information on the mechanisms of polymer transformation was obtained from dynamic quartz crystal microbalance measurements.

Clinical-scale human umbilical cord blood cell expansion in a novel automated perfusion culture system

Use of umbilical cord blood (CB) for stem cell transplantation has a number of advantages, but a major disadvantage is the relatively low cell number available. Ex vivo cell expansion has been proposed to overcome this limitation, and this study therefore evaluated the use of perfusion culture systems for CB cell expansion. CB was cryopreserved using standard methods and the thawed unpurified cells were used to initiate small-scale cultures supplemented with PIXY321,flt-3 ligand, and erythropoietin in serum-containing medium. Twelve days of culture resulted in the optimal output from most CB samples. Frequent medium exchange led to significant increases in cell (93%), CFU-GM (82%) and LTC-IC (350%) output as compared with unfed cultures. As the inoculum density was increased from 7.5 x 10(4) per cm2 to 6.0 x 10(5) per cm2, the output of cells, CFU-GM, and LTC-IC increased. Cell and CFU-GM output reached a plateau at 6.0 x 10(5) per cm2, whereas LTC-IC output continued to increase up to 1.2 x 10(6) per cm2. Because the increase in culture output did not increase linearly with increasing inoculum density, expansion ratios were greatest at 1.5 x 10(5) per cm2 for cells (6.4-fold) and CFU-GM (192-fold). Despite the lack of adherent stroma, CB cultures expressed mRNA for many growth factors (G-CSF, GM-CSF, IL-1, IL-6, LIF, KL, FL, Tpo, TGF-beta, TNF-alpha, and MIP-1alpha) that were also found in bone marrow (BM) cultures, with the exception of IL-11 (found only in BM) and IL-3 (found in neither). Culture output was remarkably consistent from 10 CB samples (coefficient of variation 0.3) indicating that the procedure is robust and reproducible. Two commercial serum-free media were evaluated and found to support only approximately 25% of the culture output as compared with serum-containing medium. Implementation of optimal conditions in the clinical scale, automated cell production system (CPS) showed that the process scaled-up well, generating 1.7 x 10(7) CFU-GM (298-fold expansion) from 1.2 x 10(8) thawed viable nucleated CB cells (n = 3). The ability to generate >10(7) CFU-GM from <15 ml of CB within this closed, automated system without the need for extensive cell manipulations will enable clinical studies to test the safety and efficacy of expanded CB cells in the transplant setting.

Applying nitrogen to grain sorghum in central Queensland: residual value and effect of fallowing and tillage practice

In the northern cereal belt of Australia, farmers are reluctant to apply nitrogen (N) fertilizers because of a perception that if N is added to the soil and no crop is subsequently planted due to lack of rain, the N is 'lost'. An experiment was conducted on a cracking clay soil over three seasons to compare the response of grain sorghum to N applied to the current crop v. N applied the previous season which was then either planted or left fallow (to simulate a missed planting opportunity). Recovery of 15~-labelled fertilizer by the crop and that remaining in the soil were simultaneously determined in microplots. The effect of tillage practice [zero (ZT) and conventional (CT)] was also examined. Sorghum grain yield responded to fresh applications of N in 1993 and 1993194 but not 1992, reflecting the importance of timing of rainfall rather than the total amount received within the season. Applications of N to the current crop always improved yield more than equivalent amounts of N applied to the previous crop. Grain yields of plots that were previously fallowed (fallow-sorghum rotation) were higher than the combined yields of sorghum-sorghum rotations, although fallowing was an inefficient means of accumulating both water and mineral N. Recovery of applied 1 5 ~ by sorghum varied from 48% in 1992 to 36% in 1993 but was not related to the overall N responsiveness of the crop. Sorghum recovered a similar proportion of 1 5 ~ from plots which had been fertilized and then fallowed the previous year compared to fresh applications to the current crop, despite the fallow plots having less 1 5 ~ in them due to losses from the previous season. Losses of 1 5 ~ from the soil/plant system varied markedly with year and appeared to be related to the pattern of rainfall occurring and its possible effect on denitrification. Tillage practice did not affect grain yields or PAWC, had minimal effect on the amount of mineral N present, and little influence on the fertilizer N requirements of sorghum per se. This study suggests that there is only a small residual value to subsequent sorghum crops of fertilizer N if added initially to a successful crop. However, if N is applied pre-plant and the crop is not planted, for example due to lack of planting rain, a large proportion of this N can remain available to the following crop depending on the nature of the subsequent rainfall.

Solar dermatitis in hatchery-reared salmonids in British Columbia

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Rickettsial septicemia in farmed Atlantic and chinook salmon in British Columbia: Clinical presentation and experimental transmission

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The use of nitrogen, phosphorus and lime to limit the competitive ability of Aristida armata in the establishment phase

The de Wit replacement series methodology was used to see if applying phosphorus, nitrogen and lime to the sandy red earth soils of mulga grazing lands can give a competitive advantage to the desirable species Cenchrus ciliaris C.V. U.S.A., Digitaria ammophila, and Thyridolepis mitchelliana over the less desirable Aristida armata. In monoculture, all species responded strongly to added nutrients, especially phosphorus. In mixtures, the preferred grasses responded even more strongly to nutrients, whereas A. armata responsed proportionally less. C. ciliaris, D. ammophila, and T. mitchelliana suppressed the growth of A. amnata in all but three situations: without added nutrients, A. armata was equally competitive with C. ciliaris; when P was added without lime, A. armata suppressed C. ciliaris; if P was added without N, A. armata suppressed T. mitchelliana. Adding either or both nitrogen or phosphorus usually increased the relative crowding coefficients, indicating that the degree of suppression of Aristida was increased by adding nutrients. Thus, C. ciliaris, D. ammophila, and T. mitchelliana appear to be equally competitive with or more competitive than A. armata if the soil is not fertilized and adding nutrients generally enhances this competitiveness. In all cases, except for A. armata/C ciliaris mixtures in soils low in phosphorus, the plants appeared to be competing for the same resource. The study demonstrated that A. armata is not a highly competitive species per se under controlled conditions and was generally suppressed by the preferred grasses, especially when nutrients were added.

Vesicular-arbuscular mycorrhiza in semi-arid pastures of south-west Queensland and their effect on growth responses to phosphorus fertilizers by grasses

Field and controlled environment studies were undertaken to determine the seasonal variation in vesicular-arbuscular mycorrhizal (VAM) propagules under different types of vegetation in the mulga (Acacia aneura) shrublands of south-western Queensland and how inoculation with VAM affects the growth and response to phosphorus fertilizers of several grasses common to this region. A most probable number (MPN) technique was used to estimate the number of viable VAM propagules under mulga shrubland and native pasture. There was a pronounced rise in MPN at a native pasture site from June to November, peaking at 1 propagule/g soil, before declining between November and May to non detectable concentrations. In the mulga shrubland site, MPN remained very low (less than 0.2 propagules/g soil) throughout the study. Pasture species in the field were screened for VAM infection in both winter and summer. Only three of the 14 species sampled were infected with VAM in winter (June) after a long drought. In contrast, 10 of the 14 species sampled in December possessed VAM-infected roots. A pot experiment was conducted to examine the influence of VAM inoculation on growth and the response to phosphate fertilizer of several important pasture grasses in pastures derived from mulga shrublands. The treatments comprised a factorial combination of inoculation or non-inoculation with VAM, four grass species (Aristida armata, Cenchms ciliaris cv. USA, Digitaria ammophilla, and Thyridolepis mitchelliana), and four rates of P fertilizer designed to range over very deficient to non-limiting for each species. All species except D. ammophilla produced growth responses to VAM inoculation. Though C. ciliaris and T. mitchelliana responded to VAM inoculation only in soil unamended with P fertilizer, A. amata showed growth responses across all P rates examined, suggesting some factor other than P was limiting this species. The growth response of the grasses to VAM inoculation was poorly correlated with the percentage of root infected with VAM. D. ammophilla had the highest levels of root infection (32%) despite producing no growth response to VAM. In contrast, T. mitchelliana had less than 2% of the root infected with VAM. All species had thin fibrous roots with long (0.35-0.47 mm), frequent root hairs. The differential growth responses to VAM inoculation of A. armata compared with the other grasses may provide a management strategy to control Aristida ingress into pastures established from mulga shrublands.

A field evaluation of an indirect fluorescent antibody-based broodstock screening test used to control the vertical transmission of Renibacterium salmoninarium in Chinook salmon (Oncorhynchus tshawytscha)

Ovarian fluid samples from erythromycin treated and untreated spawning three year old Chinook salmon were screened independently by two laboratories for the presence of Renibacterium salmoninarum using the indirect fluorescent antibody technique (IFAT). Agreement between the results of the two laboratories could be explained by chance when R. salmoninarum cell numbers as low as one per sample were considered sufficient to represent a positive result. If a positive result was considered to be the detection of larger numbers of R. salmoninarum cells (greater than 51 cells per sample), agreement increased and there was a statistically significant association between the results of the two laboratories. However, the level of agreement did not reach satisfactory levels for a population screening test. Furthermore, approximately 60% of the samples yielded false negative results when IFAT results were compared with positive culture results. These results led to the conclusion that the IFAT screening procedure, as carried out, was unsuitable for the purposes intended. Erythromycin injection of the spawning fish had no statistically significant effect on the results of the IFAT screening test.

In vitro evaluation of 6-thioguanine and alpha-interferon as a therapeutic combination in HL-60 and natural killer cells

The effect of 6-thioguanine (6-TG) and alpha-interferon (IFN-alpha) was evaluated in vitro to determine their effectiveness in combination on the therapeutically relevant events of: HL-60 cell cytotoxicity, HL-60 cell differentiation, and natural killer (NK)-cell mediated cytotoxicity. 6-TG was toxic to HL-60 cells (ID50 = 0.6 microM; 24-h exposure) while IFN-alpha (up to 1000 IU/ml) had minimal cytotoxic activity. Sequence-dependent activity was observed, inasmuch as the IFN-alpha pretreatment sequence was antagonistic, while the other schedules were additive or, possibly, synergistic. The combination of 0.5 microM 6-TG and 100 IU/ml IFN-alpha produced the same level of HL-60 cell differentiation as each agent alone, suggesting no benefit from the combination on this process. The effect of 6-TG and IFN-alpha on NK cell-mediated cytotoxicity was found to be sequence dependent. NK cell activity was markedly stimulated by IFN-alpha, whereas 6-TG alone seemed to have no direct effect. However, when the NK cells were pretreated with 100 IU/ml IFN-alpha followed by 10 microM 6-TG, the IFN-alpha-enhanced activity of NK cells was ablated. These results suggest that the immunosuppressive activity of 6-TG may be related to the acute inhibition of cytokine activation. Our results suggest that 6-TG and IFN-alpha have considerable interactions, which are sequence dependent. The optimal sequence for potential therapeutic application of these anticancer agents appears to be 6-TG pretreatment followed by IFN-alpha.

Modulation of 6-thioguanine activity by guanine in human promyelocytic leukemia HL-60 cells

The effects of guanine coadministration on the metabolism and biological activity of 6-thioguanine (6-TG) were studied in human promyelocytic leukemia cells (HL-60). Cell growth, cytotoxicity (cloning assay), and cell differentiation were measured, along with nucleotide metabolism. Guanine was efficiently salvaged by HL-60 cells; at 200 microM, guanine suppressed the formation of 6-TG mononucleotides and abolished 6-TG incorporation into nucleic acids. Similarly, guanine antagonized 6-TG cytotoxicity in a dose dependent fashion. Furthermore, guanine (200 microM) fully suppressed the 6-TG (10 microM) induced HL-60 cell differentiation, which suggests that cell differentiation at pharmacological 6-TG concentrations is dependent on the anabolism of the drug to active nucleotides. 6-TG given alone reduced GTP levels and DNA synthesis rates in HL-60 cells, while a major intracellular 6-TG metabolite, 6-thioguanosine 5'-monophosphate, accumulated to high levels (approximately 100 microM). It is suggested that accumulation of 6-thioguanosine 5'-monophosphate and a resultant partial block of the de novo biosynthesis of guanine nucleotides is responsible for 6-TG induced cell differentiation in HL-60 cells.

Correlation between ribosomal RNA production and RNA-directed fluoropyrimidine cytotoxicity

The relationship between cytotoxicity and fluoropyrimidine effects on the production of mature cytoplasmic 28S and 18S ribosomal RNA was studied in S-180 cells for the fluoropyrimidines: 5-fluorouracil (FUra), 5-fluorouridine (FUrd), 5-fluorodeoxyuridine (FdUrd), and 5'-deoxy-5-fluorouridine (5'-dFUrd). After a 6-hr drug exposure, the total cytotoxicity in the absence of added thymidine (dThd) was determined by soft-agar cloning and resulted in LC90 (lethal concentration to 90% of cells) values of 0.6 microM FdUrd, 0.7 microM FUrd, 5.3 microM FUra and 93 microM 5'-dFUrd. The RNA-directed (dThd-nonreversible) cytotoxicity was assessed by cloning the cells in the presence of 10 microM dThd. This resulted in an altered order of potency and increased LC90 values to 5.5 microM FUrd, 20 microM FUra, 265 microM FdUrd and 870 microM 5'-dFUrd. The production of mature cytoplasmic rRNA was determined by measuring the amount of [3H]cytidine incorporated into the 28S and 18S rANA species following their separation by agarose gel electrophoresis, compared with the level of [3H]cytidine incorporated into the nuclear rRNA. When all four fluoropyrimidines were compared together, the degree of inhibition of cytoplasmic rRNA production was poorly predictive of the total cytotoxicity in the absence of dThd (correlation coefficient, r = 0.77). FdUrd, in particular, had a very minor effect on rRNA production even at very toxic drug concentrations. When toxicity was assessed in the presence of dThd, however, there was a strong and significant correlation between rRNA production and RNA-directed cytotoxicity (r = 0.95, P less than 0.001), for all the fluoropyrimidines tested, including FdUrd. Thus, when the inhibition of thymidylate formation was eliminated as a site of drug action and only RNA-directed cytotoxicity was assessed, the impaired production of cytoplasmic rRNA was strongly associated with cytotoxicity. These results demonstrate that the inhibition of mature cytoplasmic rRNA production may be an important common mechanism of RNA-directed cytotoxicity for all the fluoropyrimidines, and not limited to FUrd or FUra.

Combined D-penicillamine and chloroquine treatment of rheumatoid arthritis--a comparative study

Seventy-two patients with relatively early but progressive rheumatoid arthritis were treated with chloroquine sulphate, D-penicillamine or a combination of both drugs over 1 year. Chloroquine resulted in significantly fewer side-effects but combined treatment appeared to increase the risks of toxicity. Significant clinical improvements were seen with each regimen and these were indistinguishable between treatments. However, chloroquine had less impact on haemoglobin, ESR, rheumatoid factor levels and C-reactive protein than the other treatments. Furthermore, radiological deterioration was most frequent amongst those given chloroquine alone. Combination treatment with D-penicillamine and chloroquine thus offered no advantages. Chloroquine caused fewer side-effects than both D-penicillamine and combination treatment but appeared to have a less pronounced effect on the disease process as measured by laboratory and radiological indices.

Finger flexion function in rheumatoid arthritis: the reliability of eight simple tests

The inter- and intra-observer errors of eight tests of finger flexion function were estimated from the results obtained by three observers assessing 10 patients with rheumatoid hand involvement. Measurements of finger flexion and muscle power involved both conventional and novel techniques using simple and easily constructed apparatus. For each test, measurements were in agreement between observers and were reproducible on three occasions. These tests may now be used with confidence by other investigators.

A 13-week vapor inhalation study of 3,3-dimethyl-2-butanol in Sprague-Dawley rats

Four groups of male and female Sprague-Dawley rats were exposed for 13 weeks to 3,3-dimethyl-2-butanol (PA) at concentrations of 0.00, 0.20, 1.00 or 5.00 mg/l (1 mg/l = 240 ppm). Exposures were for 6 hr per day, 5 days per week with sacrifices at 7 and 13 weeks of exposure, and at 4 weeks after exposure. The test animals were evaluated for abnormalities in physiology, behaviour, clinical laboratory parameters, and gross and microscopic morphology. No abnormalities were detected in electrocardiograms, respiratory indices, spontaneous activity, passive avoidance activity and open-field behaviour. Clinical signs related to PA exposure included alopecia, ataxia and lacrimation. There were no biologically significant between-group differences in body-weights during the study. The clinical laboratory data demonstrated a 30% increase in serum cholesterol and bilirubin at 7 weeks in high-dose males and an increase in urea nitrogen in intermediate and high-dose males at 13 weeks. There were no abnormalities in hematologic or coagulation parameters. At necropsy there were no significant gross abnormalities; however, examination of organ weights revealed enlarged kidneys in high-dose male rats at 13 weeks, enlarged ovaries in high-dose female rats at 13 weeks, and microscopic study of tissue sections revealed minimal to mild renal tubular injury in high and possibly intermediate dose males at several sacrifices. These findings suggest that the primary target organ of PA, when given by inhalation, is the kidney in male rats and possibly the ovary in female rats. The renal changes in the high-dose males were not fully reversible during the recovery period.(ABSTRACT TRUNCATED AT 250 WORDS)

Biceps tendon blocks reduction of isolated radial head dislocation

A case of an unreducible radial head dislocation found in a 7-year-old girl illustrates the frequent delay in diagnosis associated with radial head dislocation. Her initial radiographs showed the radial neck access not passing through the center of the capitulum, which is diagnostic of radial head dislocation. She had no associated injuries to the elbow joint or neurovascular structures. Closed reduction was not stable, and open reduction revealed the biceps tendon displaced posteriorly and laterally from the radial tubercle around the radial neck, which prevented stable reduction of the anteromedial dislocation of the radial head. Once it was reduced through the radial capitular joint to its normal anatomy, the reduction was stable. Following a routine postoperative course, an excellent result was obtained.