Within- and between-examiner agreement for two thyroid palpation techniques in healthy and hyperthyroid cats

Thyroid gland palpation is an important aid for diagnosing feline hyperthyroidism in an early stage to prevent development of deleterious complications. Our objectives were to assess within- and between-examiner agreement for two thyroid gland palpation techniques in cats and to correlate palpation results with ultrasonographic thyroid measurements. Nine client-owned hyperthyroid (12.6 +/- 2.4 years) and 10 healthy control cats (7.4 +/- 5.4 years) entered this prospective study. Both thyroid glands of all cats were palpated twice by three blindfolded clinicians with the classic palpation technique [technique 1 (T1)] and the technique described by Norsworthy GD, Adams VJ, McElhaney MR, Milios JA [(2002a) Relationship between semi-quantitative thyroid palpation and total thyroxine concentration in cats with and without hyperthyroidism. Journal of Feline Medicine and Surgery 4, 139-143] [technique 2 (T2)]. A semi-quantitative score from 1 to 6 was assigned to the gland size. After clipping of the ventral cervical region, another palpation session followed by ultrasonography of the thyroid glands was performed. Average weighted kappa-values within- and between-examiners were 0.864 and 0.644 for T1 and 0.732 and 0.532 for T2. T1 did lead to significantly smaller within- (P=0.007) and between-examiner (P=0.048) differences than T2. Significant correlation coefficients (P<0.001) between the palpation scores of both techniques and ultrasonographic thyroid lobe length (T1: 0.43; T2: 0.38) were observed. No significant difference before and after clipping was found (T1: P=0.503; T2: P=0.607). The first time that all cats were palpated by either technique, significant score differences between control and hyperthyroid cats were observed both for T1 (P=0.002) and T2 (P=0.003). Both feline thyroid gland palpation techniques have good within- and between-examiner agreements. Based on this study, the classic palpation technique is preferred.     

Interference of iohexol with radioiodine thyroid uptake in the hyperthyroid cat

Absorbed thyroid dose and effective half-life were determined in 46 hyperthyroid cats after treatment with a low dose (mean 111MBq) of radioiodine intravenously. Thirteen of these cats had received iohexol for glomerular filtration rate (GFR) measurement within 24h before treatment with radioiodine in view of another ongoing study at our institution. Pre-therapy values were obtained for total thyroxine (TT(4)) and for the thyroid to salivary gland ratio with sodium pertechnetate gamma-camera imaging. All cats underwent post-therapy scans at 24, 48 and 120 h for evaluation of radioactive iodine uptake (RAIU) and the effective half-life of radioiodine. The absorbed dose was calculated from the cumulative activity with Olinda software. Both groups were comparable in age, TT(4) and the ratio of thyroid activity to salivary gland activity. Statistical analysis revealed a significant decreased absorbed dose in the thyroid in the iohexol group. This decreased uptake was not accompanied by an decreased effective half-life of the radioiodine. The variation of inter-individual RAIU decreased in this group and more homogenous absorbed doses were obtained. No significant difference in outcome could be demonstrated. However, a tendency towards a higher number of residual hyperthyroidism in the iohexol group was noted (15 versus 6% in control group). This study demonstrates that iohexol interferes with the uptake of radioiodine in the hyperthyroid cat but does not provoke increased turnover. In this study, albeit including a small number of cats, outcome did not seem to be significantly affected.     

Aberrant conjunctival stricture and overgrowth in the rabbit

Six dwarf rabbits with unilateral (n = 2) and bilateral (n = 4) aberrant conjunctival growth underwent surgical correction. The applied technique involved centrifugal incisions of the overgrowing conjunctiva to the limbus and a transpalpebral fixation of the conjunctiva. In this way the conjunctival fornix was reconstructed. No relapses were noted within the observation period (5-72 months).     

Prevalence of Toxoplasma gondii infection in Belgian house cats

Five hundred and sixty seven sera of healthy house cats aged 3 months to 7 years, were examined for the presence of anti-toxoplasma antibodies by indirect immunofluorescence assay and compared to SAG1 and TLA enzyme linked immunosorbent assays as alternative test. Twenty-five percent of cats tested positive for IgG and/or IgM. Seroprevalence increased with age from 2% below 12 months of age up to 44% at age 7. Sensitivities of SAG1 and TLA ELISA were 84.1% and 88.6%, respectively. Peak levels in seroprevalence were correlated to increased IgG titers in TLA ELISA. Our results suggest that T. gondii infections are common in house cats and that there is a high chance for a negative cat to seroconvert in its second life-year.     

Distribution and activity levels of matrix metalloproteinase 2 and 9 in canine and feline osteosarcoma

Overexpression of matrix metalloproteinases (MMPs) has been associated with increased tumor aggressiveness and metastasis dissemination. We investigated whether the contrasting metastatic behavior of feline and canine osteosarcoma is related to levels and activities of MMP2 and MMP9. Zymography and immunohistochemistry were used to determine expression levels of MMP2 and MMP9 in canine and feline osteosarcoma. Using immunohistochemistry, increased MMP9 levels were identified in most canine osteosarcomas, whereas cat samples more often displayed moderate levels. High levels of pro-MMP9, pro-MMP2, and active MMP2 were detected by gelatin zymography in both species, with significantly higher values for active MMP2 in canine osteosarcoma. These findings indicate that MMP2 is probably involved in canine and feline osteosarcoma and their expression and activity could be associated with the different metastatic behavior of canine and feline osteosarcoma.     

Histopathological nerve and skeletal muscle changes in rats subjected to persistent insulin-induced hypoglycemia

New insulin analogues with a longer duration of action and a flatter pharmacodynamic profile are developed to improve convenience and safety for diabetic patients. During the nonclinical development of such analogues, safety studies must be conducted in nondiabetic rats, which consequently are rendered chronically hypoglycemic. A rat comparator model using human insulin would be valuable, as it would enable differentiation between effects related to either persistent insulin-induced hypoglycemia (IIH) or a new analogue per se. Such a model could alleviate the need for an in-study-comparator and thereby reduce the number of animals used during development. Thus, the aims of the present study were i) to develop a preclinical animal model of persistent hypoglycemia in rats using human insulin infusion for four weeks and ii) to investigate histopathological changes in sciatic nerves and quadriceps femoris muscle tissue, as little is known about the response to persistent hypoglycemia in these tissues. Histopathologic changes in insulin-infused animals included axonal degeneration and myofibre degeneration. To our knowledge, this is the first study to show that persistent IIH provokes peripheral nerve and skeletal myofiber degeneration within the same animals. This suggests that the model can serve as a nonclinical comparator model during development of long-acting insulin analogues.