Holmium-166 acetylacetonate microspheres ((166)Ho-AcAc-MS) are proposed as an intratumoral radioablation device. This article presents a pilot study in housecats with unresectable liver cancer. Feasibility and tolerability of intratumoral administrations of (166)Ho-AcAc-MS was investigated. Three cats with unresectable liver tumors of different histotype were included. One cat had hepatocellular carcinoma (HCC), one had cholangiocarcinoma (CC), and one had a malignant epithelial liver tumor (MELT) of unspecified histotype. (166)Ho-AcAc-MS were injected percutaneously under ultrasound guidance into the tumors. Followup consisted of physical examinations and hematologic and biochemical analyses. (166)Ho-AcAc-MS were administered to three liver tumor-bearing cats. The treatment was well tolerated and the clinical condition, that is body weight, alertness, mobility, and coat condition of the animals improved markedly. Most biochemical and hematologic parameters normalized shortly after treatment. Life of all cats was extended and associated with a good quality of life. The HCC cat that received 33-Gy tumor-absorbed dose was euthanized 6 months after the first administration owing to disease progression. The MELT cat received 99-Gy tumor dose and was euthanized 3 months posttreatment owing to bacterial meningitis. The CC cat received 333Gy and succumbed 4 months after the first treatment owing to the formation of a pulmonary embolism. Percutaneous intratumoral injection of radioactive (166)Ho-AcAc-MS is feasible in liver tumor-bearing cats. The findings of this pilot study indicate that (166)Ho-AcAc-MS may constitute safe brachytherapeutic microspheres and warrant studies to confirm the clinical utility of this novel brachytherapy device.

Objectives: The objective of this study was to investigate serum cystatin C (sCysC) and urinary cystatin C (uCysC) in cats with hyperthyroidism and cats with feline immunodeficiency virus (FIV).Methods: Thirty cats with FIV, 26 hyperthyroid cats and 28 healthy cats were included. sCysC and uCysC:creatinine (uCysC/uCr) ratio were measured with a human particle-enhanced nephelometric immunoassay, previously validated for feline CysC measurement. Routine renal variables (serum creatinine [sCr], urine specific gravity, urinary protein:creatinine ratio [UPC]) were also measured in the three groups.Results: Cats with hyperthyroidism had significantly higher sCysC and higher uCysC/uCr ratio, lower sCr and a higher UPC than healthy cats. Cats with FIV infection did not show a significantly higher sCysC concentration but had a significantly higher sCr and UPC than healthy cats. uCysC could be detected in only four of them.Conclusions and relevance: This study demonstrated that sCysC is increased in cats with hyperthyroidism, in contrast with sCr, but not in cats with FIV. Many hyperthyroid cats, but only four cats with FIV, had an elevated uCysC/uCr ratio. Further studies may reveal if uCysC might be a valuable marker for tubular dysfunction in cats.

Portosystemic shunts (PSS), congenital or acquired, occur uncommonly in the feline population. The diagnostic approach is similar to one in dogs suspected of a PSS based on the clinical signs and haematological and biochemical changes. Diagnostic imaging, however, is key for the confirmation of a PSS. Although abdominal ultrasound is the first-choice diagnostic imaging modality, the results are not always unequivocal. Transsplenic portal scintigraphy (TSPS) using^99mTc-pertechnetate is a well-established technique in canine medicine, providing relatively fast and easy confirmation of the presence or absence of a PSS. As the prevalence of PSS is much lower in the feline population, this technique has not been widely used in cats. This retrospective study of 12 cases gives an overview of the potential of TSPS in the diagnostic work-up of PSS in cats (2005–2012).