Tear-film osmolarity in normal cats and cats with conjunctivitis

Objective To compare the tear‐film osmolarity of normal cats and cats with conjunctivitis. Animal studied The population consisted of shelter, research, and privately owned cats. Procedures Cats were classified as normal or having conjunctivitis. An ophthalmic examination including Schirmer tear test (STT), fluorescein staining, tear‐film break‐up time (TFBUT), intraocular pressure (IOP), and slit‐lamp biomicroscopy of the anterior segment was performed. The severity of conjunctivitis was graded and assigned a numerical score. The Tear Lab^TM Osmolarity System was utilized to determine the tear‐film osmolarity. Unpaired t‐tests were used to compare tear‐film osmolarity, TFBUT, IOP, and STT of the two groups. Results A total of 93 cats (186 eyes) were examined. There were 37 normal cats (74 eyes) and 39 conjunctivitis cats (78 eyes). The mean age was 2.34 years. There was no statistical difference (P = 0.2065) between the median tear‐film osmolarity of normal cats (328.5 ± 17.94 mOsms/L) and conjunctivitis cats (325.0 ± 24.84 mOsms/L). Cats with conjunctivitis had an accelerated TFBUT (P < 0.0001) and lower IOPs (P < 0.0001) as compared to normal cats. No statistical difference was found between STT values (P = 0.1304). Conclusions The median tear‐film osmolarity of normal cats was 328.5 mOsms/L. Despite the accelerated TFBUT, conjunctivitis did not cause a statistically significant change in tear‐film osmolarity. The Tear Lab^TM Osmolarity System was easily used and well tolerated by the cats in the study.     

Pharmacokinetics of methimazole in normal cats and cats with hyperthyroidism

The intravenous and oral disposition of the antithyroid drug methimazole was determined in 10 clinically normal cats and nine cats with naturally occurring hyperthyroidism. After intravenous administration of 5 mg methimazole, the mean residence time was significantly (P less than 0.05) shorter in the cats with hyperthyroidism than in the normal cats, but there was no significant difference between the mean values for total body clearance (CL), steady state volume of distribution (Vdss), terminal elimination rate constant (ke), or serum terminal half-life (t1/2) in the two groups of cats. After oral administration, the mean bioavailability of methimazole was high in both the normal cats (77.6 per cent) and cats with hyperthyroidism (79.5 per cent). The values for mean residence time, ke and serum terminal t1/2 after oral dosing were significantly shorter in the cats with hyperthyroidism than in the normal cats. However, after oral administration of methimazole there were no significant differences between the mean values for CL, Vdss, bioavailability and maximum serum concentrations or the time for maximal concentrations to be reached in the two groups of cats. Overall, most pharmacokinetic parameters for methimazole were not altered by the hyperthyroid state. However, the cats with hyperthyroidism did show a trend toward faster elimination of the drug compared with the normal cats, similar to what has been previously described for the antithyroid drug propylthiouracil in cats. These results also indicate that methimazole is well absorbed when administered orally and has a higher bioavailability than that of propylthiouracil in cats with hyperthyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum proteins in normal cats and cats infected with Aelurostrongylus abstrusus

Serum proteins were evaluated by cellulose acetate electrophoresis in cats prior to and every 2 weeks for 24 weeks after oral infection with third stage larvae of Aelurostrongylus abstrusus. Evaluation of electrophoretograms was standardized by determination of electrophoretic migration ratios. Six fractions of serum proteins were consistently identified: albumin and alpha 1, alpha 2, beta 1, beta 2, and gamma globulin. Relative and absolute concentrations of each serum protein fraction were determined. The only changes found were a decrease in concentration of alpha globulins and an increase in concentration of beta 1 globulins. These changes were mild, however, so that the the concentrations for infected cats were still within 1 SD of the control concentrations. Apparently serum electrophoresis is not a useful diagnostic test for aelurostrongylosis.     

Blood pressure assessment in healthy cats and cats with hypertensive retinopathy

OBJECTIVE: To determine whether there was an association between hypertensive retinopathy and high systolic, diastolic, and mean arterial blood pressures in cats. ANIMALS: 181 cats. PROCEDURE: Systolic, diastolic, and mean arterial blood pressures were measured by use of a noninvasive oscillometric technique. The range of blood pressure measurements in healthy cats from various age groups was determined. Associations among systolic, diastolic, and mean arterial blood pressure; hypertensive retinopathy; hyperthyroidism; left ventricular cardiac hypertrophy; chronic renal failure; and serum biochemical abnormalities were determined. RESULTS: All blood pressure measurements increased with age in healthy cats. The frequency of hypertensive retinopathy also increased with age and with blood pressure, and hypertensive retinopathy was particularly found in cats with systolic blood pressures > 168 mm Hg. There was an increased risk for hypertensive retinopathy in cats that were female, > 10 years old, and neutered. The risk of chronic renal failure also increased as blood pressure, particularly systolic blood pressure, increased. CONCLUSIONS AND CLINICAL RELEVANCE: Hypertensive retinopathy was common in cats > or = 10 years of age and was associated with systolic blood pressures > 168 mm Hg when measured by the noninvasive oscillometric technique.     

Ringworm in dogs and cats

Ringworm is an uncommon disease of dogs, but cats, especially the longhaired breeds, are more frequently infected. Of the several dermatophytes involved, Microsporum canis causes 94 per cent of ringworm in cats and 65 per cent in dogs. This species is highly contagious for man but the true incidence of human infection is unknown. Ringworm caused by M canis usually responds readily to treatment, but when the infection establishes in a colony of cats, eradication can be difficult and expensive. Other forms of ringworm in dogs and cats are caused by dermatophytes acquired from wild animals, mainly small rodents such as mice and voles. This is an uncommon and trivial disease of cats, but some infections in dogs can be remarkably persistent and difficult to resolve.     

Histoplasmosis in dogs and cats

Histoplasma capsulatum is endemic throughout most of the United States with a high prevalence of infections in the Midwest and South. Histoplasmosis is the second most common systemic fungal disease in cats that may be more susceptible than dogs. Infection occurs by inhalation of conidia from the mycelial phase, which subsequently convert to the yeast form. Histoplasma capsulatum is phagocytized and harbored by cells of the mononuclear phagocyte system. Infection may be subclinical or cause clinical pulmonary granulomatous disease or dissemination. Disseminated disease predominantly affects the liver, spleen, gastrointestinal tract, bone and bone marrow, integument, and eyes. Primary gastrointestinal histoplasmosis also occurs. Clinical signs of histoplasmosis often are nonspecific, including chronic wasting, fever, anorexia, respiratory signs, and lameness. Gastrointestinal signs (eg, diarrhea with hematochezia or melena) are common in dogs. The definitive diagnosis is made by identification of the yeast in tissue samples. Itraconazole is the treatment of choice.     

Proteinuria in dogs and cats

Proteinuria is defined as the presence of protein in the urine. Normally, circulating serum proteins are blocked by the glomerulus due to size and/or charge. Any small proteins that pass through a healthy glomerulus are reabsorbed by the renal tubules or broken down by renal tubular epithelial cells. Persistent proteinuria, in the absence of lower urinary tract disease or reproductive tract disease, is usually an indication of renal damage or dysfunction. Less commonly persistent proteinuria can be caused by increased circulating levels of low molecular weight proteins. This article reviews mechanisms of proteinuria in dogs and cats and discusses the importance of screening for and ultimately treating proteinuria.     

Sporozoa in dogs and cats

SUMMARY Faecal samples from 110 dogs and 71 cats were examined for sporozoan parasites by flotation. Isospora spp were present in 5.5% dogs and 4.2% cats; Sarcocystis spp in 20.9% dogs and 1.4% cats. 74.5% dogs and 77.5% cats were fed raw meat from various sources; beef was fed most often. Animals fed raw meat were more frequently infected with protozoa. No Toxoplasma oocysts were found. The results are compared with those from other surveys in Australia and New Zealand.