We report here the clinical features and outcomes of two patients who presented idiopathic tubulo-interstitial nephritis and uveitis syndrome (TINU syndrome) with ocular disease following the onset of nephropathy. The initial symptoms were renal impairment with asthenia, anorexia and weight loss. An increase in urinary beta2-microglobulin was noticed at the initial checkup in both patients. Renal biopsies showed interstitial cellular infiltration without granulomas or tubular atrophy. No glomerular and vascular alterations were seen and immunofluorescent staining was uniformly negative. Systemic steroid therapy was given and renal function returned to normal within three months. Anterior uveitis occurred in both patients eight months later and responded well to local steroid therapy. Renal involvement in TINU syndrome mostly has a favorable outcome. Despite the possibility of spontaneous regression, systemic steroids may be beneficial in reducing the development of interstitial fibrosis.
Zero Tolerance Testing
Zero tolerance testing is not testing down to "zero" molecules, which no chemist can accomplish, but rather testing to the limit of detection (LOD) of the best available technology. In other words, "zero tolerance" refers to the racing regulators' philosophy in regulating drug use in race horses—even trace amounts of drugs are not tolerated.  While detecting trace amounts may be an entirely appropriate approach for performance altering substances which have no approved veterinary use, it is not considered appropriate for therapeutic medications which may be present in trace amounts having negligible or no pharmacological activity. Therapeutic medications are approved substances used to maintain the health and welfare of horses.