Triazine-based antiprotozoal agents are known for their lipophylic characteristics and may therefore be expected to be well absorbed following oral administration. However, although an increase in lipid solubility generally increases the absorption of chemicals, extremely lipid-soluble chemicals may dissolve poorly in gastrointestinal (GI) fluids, and their corresponding absorption and bioavailability would be low. Also, if the compound is administered in solid form and is relatively insoluble in GI fluids, it is likely to have limited contact with the GI mucosa, and therefore, its rate of absorption will be low. Based on the above considerations, we sought a solvent with low or no toxicity that would maintain triazine agents in solution. As the oral route is most preferred for daily drug therapy, such a solvent would allow an increased rate of absorption following oral administration. In present study, it was demonstrated that dimethylsulfoxide (DMSO) increased the oral bioavailability of toltrazuril sulfone (Ponazuril) threefold, relative to oral administrations of toltrazuril sulfone suspended in water. The cross-over study of toltrazuril sulfone formulated in DMSO indicated that the absolute oral bioavailability of toltrazuril sulfone in DMSO is 71%. The high bioavailability of the DMSO-preparation suggests that its daily oral administration will routinely yield effective plasma and cerebral spinal fluid (CSF) concentrations in all horses treated. Also, this improved formulation would allow clinicians to administer loading doses of toltrazuril sulfone in acute cases of Equine Protozoal Myeloencephalitis. Another option would involve administration of toltrazuril sulfone in DMSO mixed with feed (1.23 kg daily dose) meeting the US Food and Drug Administration (FDA) recommendations for the levels of DMSO permissible in pharmaceutical preparations.
Larvae of the bruchid beetle Caryedes brasiliensis (Bruchidae) develop entirely within the seed of the neotropical legume Dioclea megacarpa. The seed contains an appreciable concentration of L-canavanine, a potent antimetabolite and structural analog of L-arginine. This bruchid beetle uses the nitrogen stored in this toxic allelochemical as an effective dietary nitrogen source for amino acid biosynthesis.
(2013). The contribution of the HIV specialist nurse to HIV care : a scoping review. Journal of clinical nursing, 22 (23-24), 3349-3360. Copyright and re-use policySee http://shura.shu.ac.uk/information.html Sheffield Hallam University Research Archivehttp://shura.shu.ac.ukThe contribution of the HIV specialist nurse to HIV care: a scoping review ABSTRACT Aims and ObjectivesTo systematically identify and critically examine the evidence on the contribution of the HIV nurse specialist to provision of HIV care in the UK and other developed countries. BackgroundThe HIV clinical nurse specialist role has evolved over the past two decades in response to changes in two areas of HIV care: Firstly changes in the treatment and care of those with HIV and secondly changes and development in advanced nursing practice. The challenges facing HIV care require the development of innovative services including a greater contribution of HIV specialist nurses. A review of current evidence is required to inform developments. Design A scoping review. Methods A broad search strategy was used to search electronic databases. Grey literature was accessed through a variety of approaches. Preference was given to UK literature with inclusion of international publications from other developed countries where relevant. Results 14 articles were included. Four themes were identified: The diversity of the clinical role; a knowledge and skills framework for HIV nursing practice; the education and training role of the HIV nurse specialist; and the effectiveness of the HIV nurse specialist. The findings mainly focus on the clinical aspects of the role with little evidence concerning other aspects. There is limited evidence to indicate clinical effectiveness. Conclusions HIV care is facing substantial challenges and there is a clear need to develop effective and efficient services, including expanding the contribution of HIV nurse specialists. Such developments need to occur within a framework that optimises nursing contribution and measures their impact on HIV care. This review provides a baseline to inform such developments. Clinical relevanceCurrent understanding of HIV nurse specialist provision to inform service development and optimisation of patient care.
An epidemiological association among black cherry trees (Prunus serotina), eastern tent caterpillars (Malacosoma americana), and the spring 2001 episode of mare reproductive loss syndrome in central Kentucky focused attention on the potential role of environmental cyanogens in the causes of this syndrome. To evaluate the role of cyanide (CN (-)) in this syndrome, a simple, rapid, and highly sensitive method for determination of low parts per billion concentrations of CN (-) in equine blood and other biological fluids was developed. The analytical method is an adaptation of methods commonly in use and involves the evolution and trapping of gaseous hydrogen cyanide followed by spectrophotometric determination by autoanalyzer. The limit of quantitation of this method is 2 ng/mL in equine blood, and the standard curve shows a linear relationship between CN (-) concentration and absorbance (r >. 99). The method throughput is high, up to 100 samples per day. Normal blood CN (-) concentrations in horses at pasture in Kentucky in October 2001 ranged from 3-18 ng/mL, whereas hay-fed horses showed blood CN (-) levels of 2-7 ng/mL in January 2002. Blood samples from a small number of cattle at pasture showed broadly similar blood CN (-) concentrations. Intravenous administration of sodium cyanide and oral administration of mandelonitrile and amygdalin yielded readily detectable increases in blood CN (-) concentrations. This method is sufficiently sensitive and specific to allow the determination of normal blood CN (-) levels in horses, as well as the seasonal and pasture-dependent variations. The method should also be suitable for investigation of the toxicokinetics and disposition of subacutely toxic doses of CN (-) and its precursor cyanogens in the horse as well as in other species.
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