Research Articles (Biomedical Research Centre)

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    Isolation of seselin from Clausena anisata (Rutaceae) leaves and its effects on the feeding and development of Lucilia cuprina larvae may explain its use in ethnoveterinary medicine
    (Elsevier, 2013-12) Mukandiwa, Lillian; Ahmed, Ahmed; Eloff, Jacobus Nicolaas; Naidoo, Vinny; kobus.eloff@up.ac.za
    ETHNOPHARMACOLOGICAL RELEVANCE : The leaves of Clausena anisata are used traditionally to expel maggots from wounds of animals in Zimbabwe. We have previously proved in the laboratory that the plant certainly affects the behaviour and growth of blowfly larvae. The objective of this study was to isolate and identify the active compounds responsible for this activity.MATERIALS AND METHODS : The acetone extract of C. anisata leaf powder was separated by solvent-solvent partition into five fractions. The n-hexane fraction was the most active in the larvicidal assay and therefore subjected to open column chromatography on silica gel. RESULTS : The isolated compound was identified by nuclear magnetic resonance (NMR) and mass spectroscopy (MS) as the pyranocoumarin, seselin, chemically known as 2',2'- dimethylpyranocoumarin . It inhibited feed intake in the first and second instars of blowflylarvae at the minimum concentration tested of 1 ppm resulting in significant lower mass pupae (13.5 ± 0.5 mg and 22.4 ± 0.4 mg for the first and second instar larvae respectively) compared to the solvent control group (26.19 ± 0.8 mg) (p < 0.05). CONCLUSIONS : This is the first report of the isolation of seselin from the leaves of C. anisata and the first report of the compound having an effect against blow fly larvae.
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    Co-infection with Anaplasma platys, Bartonella henselae and Candidatus Mycoplasma haematoparvum in a veterinarian
    (BioMed Central, 2013-04-15) Maggi, Ricardo G.; Mascarelli, Patricia E.; Havenga, Lauren N.; Naidoo, Vinny; Breitschwerdt, Edward B.
    BACKGROUND: During a two year period, a 27-year-old female veterinarian experienced migraine headaches, seizures, including status epilepticus, and other neurological and neurocognitive abnormalities. Prior to and during her illness, she had been actively involved in hospital-based work treating domestic animals, primarily cats and dogs, in Grenada and Ireland and anatomical research requiring the dissection of wild animals (including lions, giraffe, rabbits, mongoose, and other animals), mostly in South Africa. The woman reported contact with fleas, ticks, lice, biting flies, mosquitoes, spiders and mites and had also been scratched or bitten by dogs, cats, birds, horses, reptiles, rabbits and rodents. Prior diagnostic testing resulted in findings that were inconclusive or within normal reference ranges and no etiological diagnosis had been obtained to explain the patient’s symptoms. METHODS: PCR assays targeting Anaplasma spp. Bartonella spp. and hemotopic Mycoplasma spp. were used to test patient blood samples. PCR positive amplicons were sequenced directly and compared to GenBank sequences. In addition, Bartonella alpha Proteobacteria growth medium (BAPGM) enrichment blood culture was used to facilitate bacterial growth and Bartonella spp. serology was performed by indirect fluorescent antibody testing. RESULTS: Anaplasma platys, Bartonella henselae and Candidatus Mycoplasma haematoparvum DNA was amplified and sequenced from the woman’s blood, serum or blood culture samples. Her serum was variably seroreactive to several Bartonella sp. antigens. Despite symptomatic improvement, six months of doxycycline most likely failed to eliminate the B. henselae infection, whereas A. platys and Candidatus M. haematoparvum DNA was no longer amplified from post-treatment samples. CONCLUSIONS: As is typical of many veterinary professionals, this individual had frequent exposure to arthropod vectors and near daily contact with persistently bacteremic reservoir hosts, including cats, the primary reservoir host for B. henselae, and dogs, the presumed primary reservoir host for A. platys and Candidatus Mycoplasma haematoparvum. Physicians caring for veterinarians should be aware of the occupational zoonotic risks associated with the daily activities of these animal health professionals.
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    Antebrachial chondrodysplasia in New Zealand white rabbits (Oryctolagus cuniculus)
    (South African Veterinary Association, 2011-06) Pulker, Tamsyn A.; Carstens, Ann; Williams, June Heather; tamsyn.pulker@up.ac.za
    Rabbits obtained from a South African rabbit breeder exhibited deformities of the distal forelimbs. The clinical, radiological and histological presentation of mid-antebrachial valgus formation (a.k.a distal foreleg curvature) in these rabbits was consistent with an autosomal recessive trait associated with a chondrodystrophic lesion of the distal ulna epiphysis 1st described in the 1960s. The impact this might have on South African farming enterprises and laboratory facilities has not been established, but the heritability and welfare implications of this condition make it a concern. Mildly affected animals can adapt to the deformity with some housing adjustments, but severely affected animals may require humane euthanasia.
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    99mTc-labelled biguanide derivatives : chemical speciation modelling thereof and evaluation in vervets
    (Springer, 2010-01) Zeevaart, Jan Rijn; Wagener, Judith Marie; Neves, Maria; Costa, Maria Ceu; Rodrigues, Cristina; Dithebe, Midred K.; Kilian, Elmare; Cukrowski, Ignacy
    99mTc-DMSA (dimercaptosuccinic acid) is known to be a safe and effective agent for static renal imaging. However, it has a long uptake time which is a limiting factor in diagnostic procedures and also leads to a relatively high radiation dose being administered to patients. There is a constant search for possible new renal imaging agents with a good resolution, kidney/liver contrast and low radiation dose to all organs. A series of biguanide derivatives (potential as non-insulin-dependent diabetes mellitus agents) labelled with 99mTc were investigated as potential alternative kidney-imaging agents on theoretical grounds (in silico) and their biodistribution (in vivo) verified in a limited number of animal experiments. Such a dual approach has the benefit that it reduces the number of animal experiments needed to evaluate a potential radiopharmaceutical. The blood plasma model shows little or no complexation of the biguanide type ligands by the metal ions in blood plasma. It was therefore expected that these ligands will clear rapidly through the kidneys and liver (increased lipophilicity). These predictions were verified by studies on single vervets comparing them with 99mTc-DMSA as gold standard. All the biguanide derivatives labelled with 99mTc show liver, kidney and gallbladder uptake in vervets. It was shown that the agent 99mTc-CBIG (carboxylbiguanide) has a very fast kidney clearance, which will reduce the dose to organs (as experienced for 99mTc-DMSA), although it’s potential as a kidney agent is limited by its gallbladder uptake.