Letters

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The enantiomeric composition of triadimenol produced during metabolism of triadimefon by fungi. Part II: Differences between fungal species

The fungi Coriolus versicolor, Cladosporium cucumerinum, Botrytis cinerea and Fusarium culmorum, in shake culture, metabolised triadimefon to triadimenol. Analyses by gas–-liquid chromatography of the triadimenol showed that the fungi produced different qualitative and quantitative combinations of the four possible enantiomers, and that these differences were reproducible. The relationship between the enantiomeric composition of the triadimenol produced and the sensitivity of the test fungi to triadimefon, is discussed in the light of published data on the differences in antifungal activity shown by these enantiomers.     

Back muscle necrosis of pigs.

The clinical signs and pathological features of back muscle necrosis (BMN) in four pigs from three English pig herds were similar to those recorded in pigs from mainland Europe. The observations made support the view that BMN is a special manifestation of the porcine stress syndrome. Diagnosis of acute BMN can be made clinically supported by the analysis of plasma creatine phosphokinase activity and can be confirmed post mortem by macroscopic and microscopic observation on the back muscles.     

Response of susceptible and resistant peach-potato aphids Myzus persicae (Sulz.) to insecticides in leaf-dip bioassays

The response of susceptible (S), moderately resistant (R₁) and strongly resistant (R₂) peach-potato aphids, Myzus persicae (Sulz.) to organophosphorus, carbamate and pyrethroid insecticides was tested by a leaf-dip bioassay. The aphids were placed on potato leaves (dipped in insecticide solutions 1–2 or 24 h before infestation) and their mortality examined 48 h later. R₁ aphids were virtually susceptible to most of the carbamates, demephion and acephate, but were slightly to moderately resistant (2.1–9.4 times) to permethrin, cypermethrin and (S)-α-cyano-3-phenoxybenzyl (1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate (I), (NRDC 161), to 5,6,7,8-tetrahydro-2-methylquinolin-4-yl dimethylcarbamate (II), (Hoechst 25 682) and demeton-S-methyl. R₂ aphids resisted more strongly or very strongly (between 65 and 1280 times) the pyrethroids, demeton-S-methyl (×94), II (×83) and demephion (×9), and were slightly to moderately (2–5 times) resistant to acephate, pirimicarb, ethiofencarb and 2-(dimethylcarbamoyloxyimino)-3-methoxyimino-N,N- dimethylbutyramide (III), (DPX 3853). Both resistant strains were susceptible to nitrilacarb [4,4-dimethyl-5-(methylcarbamoyloxyimino)pentanenitrile] complex (1:1) with zinc chloride (IV), (AC 85 258). The implications of these results in terms of practical aphid control are discussed.     

Modifiers of gastrointestinal motility of cattle.

Little clinically relevant, evidence-based data about the effect of motility modifiers on the GI tract of cattle are currently available. Additionally, some of the published results seem to be contradictory. Three main facts explain this apparent discrepancy: (1) Results may not be transferred from one species to another, because presence, concentration, location, distribution, and function of specific receptors may differ significantly among species. (2) The lack of a significant effect on smooth muscle preparations in vitro does not necessarily exclude a certain drug's motility-modifying property on affected animals in vivo. Certain drugs bind to receptors outside the myenteric plexus. Others, such as lidocaine and adrenergic-, dopaminergic-, and opioid-antagonists increase only GI motility, if inhibitory reflexes or a hyperactive state of the inhibitory sympathetic nervous system preexists. (3) Effects of motility modifiers as found in healthy experimental animals in vivo may not be similar to those found in spontaneously diseased animals. Accurate and reliable data on the effect of modifiers of GI motility of cattle will be obtained only from double-blinded, evidence-based, in vivo studies on spontaneously affected animals. Because well-documented results from such studies are extremely rare, intensive research in this field is warranted in the future.     

Normal behavior and the clinical implications of abnormal behavior in guinea pigs.

Cavies are becoming more popular as pets because they are relatively easy to care for and provide never-ending love and entertainment with their curious but gentle nature. As with other species, the best way to learn about guinea pig behavior is to own guinea pigs. Understanding normal behavior provides the practitioner with the ability to more easily recognize pathology and abnormal behavior. This allows the veterinarian to provide necessary supportive care and pain management more quickly while performing diagnostics and determining the need for therapeutics. Understanding the behavior of cavies allows the clinician to better educate guinea pig-owning clients and to better and more quickly serve the needs of their guinea pig patients.     

Serum troponin I levels in hyperthyroid cats before and after treatment with radioactive iodine

A raised concentration of serum cardiac troponin I (cTnI) is a sensitive marker of cardiac myocyte injury in the cat and assays developed for its measurement in human patients have been validated in the cat. Raised levels have been associated with a number of cardiac insults including hypertrophic cardiomyopathy and trauma. Hyperthyroidism is a common disease of older cats and excess thyroid hormone is known to produce significant cardiovascular effects in this species. This study evaluated the effect of treatment for hyperthyroidism with radioactive iodine on cTnI concentration, assessed the association between thyroxin levels and glomerular filtration rate (GFR) and cTnI concentration in cats treated for hyperthyroidism and described changes in echocardiographic parameters following treatment. Prior to the treatment serum cTnI was measured and echocardiography performed, thyroxin, cTnI, and echocardiography were then repeated at various time points following radioisotope therapy. The results show that higher thyroxin levels were significantly (P=0.002) associated with a higher likelihood of the cat presenting with detectable levels of cTnI. No significant association was found between GFR and presence of detectable levels of cTnI. Furthermore the results indicate that the effects of hyperthyroidism on echocardiographic parameters appear considerably less in this study than in previous studies and that the main outcome of treatment on these parameters is a significant reduction in fractional shortening (P=0.006). These results suggest that chronic exposure to excess thyroid hormone may induce myocyte damage of sufficient severity to raise serum cTnI concentration in a proportion of cats that resolves following establishment of a euthyroid state.