Normal Domestic Cats Research Articles

The post-natal development of intraocular pressure in normal domestic cats (Felis catus) and in feline congenital glaucoma

Intraocular pressure (IOP) is the most consistent risk factor for progressive vision loss in glaucoma. Cats with recessively inherited feline congenital glaucoma (FCG) exhibit elevated IOP with gradual, painless progression of glaucoma similar to humans and are studied as a model of glaucoma in humans and animals. Here, post-natal development of IOP was characterized in normal domestic cats and in cats with FCG caused by a homozygous LTBP2 mutation. Rebound tonometry (TonoVet®, ICare Oy, Finland) was used to measure IOP non-invasively, 2–3 times weekly in 63 FCG and 33 normal kittens, of both sexes, from eyelid opening until 3–6 months of age. IOPs in the left and right eyes of both FCG and normal kittens were compared by paired t-test and linear regression. One-way ANOVA and Tukey-Kramer post-tests were used to compare IOP of cats grouped by age and disease status. A p-value <0.05 was considered significant. In the second week of life, mean IOP was 7.16 mmHg (SD = 1.3) in normal kittens and 8.72 mmHg (SD = 1.4) in kittens with FCG. Mean IOP at age 10 weeks was significantly higher in FCG (19.8 mmHg; 95% CI = 17.7, 21.9 mmHg) than in normal kittens (13.2 mmHg; 95% CI = 11.9, 14.5 mmHg). At 3 months of age, IOP in normal cats reached adult values while IOP in FCG cats continued to increase through at least six months of age. These results provide ranges for normal IOP values in young kittens and confirm that IOP is significantly higher than normal by 10wks of age in this spontaneous feline glaucoma model.

Experimental Verification of the Effects on Normal Domestic Cats by Feeding Prescription Diet for Decreasing Stress

The objective of this study was to evaluate the effects of diet on the feline stress response by measuring plasma and urinary cortisol. A study diet was developed with a unique combination of nutrients that supports the management of stressful situations. The specific formulation of the diet included alpha-casozepine, which is believed to have an anxiolytic effect, and tryptophan supplementation. Tryptophan is the precursor for the synthesis of the neurotransmitter serotonin. Twenty-one indoor cats were fed with the study diet (n = 10) or a control diet (n = 11) for 8 weeks, after which physiological responses were evaluated. The study diet significantly increased the ratio of plasma tryptophan to large neutral amino acids and decreased urinary cortisol concentrations after being consumed daily for 8 weeks, but there was no effect on plasma cortisol levels following a stressful event (veterinary examination and blood draw). Further studies, such as behavioral analyses, are needed to clarify the effects of the study diet.

Refractive states of eyes and associations between ametropia and age, breed, and axial globe length in domestic cats

To determine the refractive states of eyes in domestic cats and to evaluate correlations between refractive error and age, breed, and axial globe measurements. 98 healthy ophthalmologically normal domestic cats. The refractive state of 196 eyes (2 eyes/cat) was determined by use of streak retinoscopy. Cats were considered ametropic when the mean refractive state was ≥ ± 0.5 diopter (D). Amplitude-mode ultrasonography was used to determine axial globe length, anterior chamber length, and vitreous chamber depth. Mean ± SD refractive state of all eyes was -0.78 ± 1.37 D. Mean refractive error of cats changed significantly as a function of age. Mean refractive state of kittens (≤ 4 months old) was -2.45 ± 1.57 D, and mean refractive state of adult cats (> 1 year old) was -0.39 ± 0.85 D. Mean axial globe length, anterior chamber length, and vitreous chamber depth were 19.75 ± 1.59 mm, 4.66 ± 0.86 mm, and 7.92 ± 0.86 mm, respectively. Correlations were detected between age and breed and between age and refractive states of feline eyes. Mean refractive error changed significantly as a function of age, and kittens had greater negative refractive error than did adult cats. Domestic shorthair cats were significantly more likely to be myopic than were domestic mediumhair or domestic longhair cats. Domestic cats should be included in the animals in which myopia can be detected at a young age, with a likelihood of progression to emmetropia as cats mature.

Standardization of Some Electrocardiographic Parameters of Captive Leopard Cats (Leopardus tigrinus)

Thirty-three captive leopard cats, Leopardus tigrinus, were anesthetized with xylazine (1-2 mg/kg) and ketamine (10 mg/kg), and electrocardiograph (ECG) tests were recorded in all leads with 1 cm = 1 mV sensibility and 25 mm/sec speed repeating DII lead at 50 mm/sec speed with the same sensibility. Results expressed by mean and standard deviation were: heart rate (HR) = 107 +/- 17 (bpm); P-wave = 0.048 +/- 0.072 (s) x 0.128 +/- 0.048 (mV); PR interval = 0.101 +/- 0.081 (s); QRS compound = 0.053 +/- 0.012 (s) x 1.446 +/- 0.602 (mV); QT interval = 0.231 +/- 0.028 (s); R-wave (CV6LL) = 1.574 +/- 0.527 (mV); R-wave (CV6LU) = 1.583 +/- 0.818 (mV); heart rhythm: normal sinus rhythm (15.2%), sinus rhythm with wandering pacemaker (WPM) (60.6%), sinus arrhythmia with WPM (24.2%); electric axis: between +30 degrees and +60 degrees (6.1%), +60 (6.1%), between +60 degrees and +90 degrees (57.6%), +90 degrees (9%), between +90 degrees and +120 degrees (21.2%); ST segment: normal (75.7%), elevation (18.2%), depression (6.1%); T-wave polarity (DII): positive (100%); T-wave (V10): absent (6.1%), negative (63.6%), positive (18.2%), and with interference (12.1%). Through ECG data comparison with other species, unique features of Leopardus tigrinus' (leopard cat) ECG parameters were detected. Some of the study animals presented with an R-wave amplitude that was indicative of left ventricle overload according to patterns for normal domestic cats (Felis cati). Echocardiographic exams revealed normal heart cavities' function and morphology. The aim of this study was to establish some electrocardiographic parameters of captive L. tigrinus.

DNA Methylation Status in Somatic and Placenta Cells of Cloned Cats

We recently produced 11 cloned kittens by somatic cell nuclear transfer (SCNT) using fibroblasts from a feline fetus (donor A, three kittens), an adult domestic cat (donor B, one kitten), and a deaf adult Turkish Angora cat (donor C, seven kittens). Two kittens were stillborn and three died a month after birth. The donor C-derived kittens did not share their donor's eye color or deafness. To test whether this and the low cloning success rate are due to epigenetic modifications, we compared the methylation of somatic and placental cells from the cloned cats and domestic normal cats by bisulfite mutagenesis sequencing analysis. The DNA methylation of somatic cells from the cloned kittens ranged from 78.0% to 88.9%, and did not differ significantly depending on whether they were stillborn, died early after birth, or were healthy. Donors B and C showed similar levels of methylation (77.0% and 79.1%, respectively), as did somatic cells from normal domestic and Turkish Angora cats (range, 75.7-88.0%). However, donor A showed less methylation (70.6%) than the somatic cells from the kittens derived from it (range, 82.2-88.9%). Moreover, placental cells from three donor C-derived kittens showed significantly higher DNA methylation (range, 76.7-80.5%) than placental cells from normal domestic cats (range, 64.2-74.9%). Thus, methylation of satellite regions in somatic cells may not be responsible for the stillbirth, early death, or different eye and hearing attributes of cloned cats. However, hypermethylation in the placenta of cloned cats may be responsible for low success rates in cloning cats.

29 COMPARISON OF DNA METHYLATION RATES BETWEEN CLONED CATS AND DOMESTIC CATS

Many mammalian species have recently been successfully cloned using somatic cells. We have produced cloned kittens by somatic cell nuclear transfer (SCNT). The cloning of mammals by SCNT requires epigenetic reprogramming of the differentiated state of donor cells. We recently observed that feline catus satellite DNA regions exhibit DNA methylation in the donor and somatic cells of a cloned cat. The cause of variation could lie in alterations occurring at different steps of the cloning procedure or incomplete reestablishment of DNA methylation patterns. This study was conducted to determine the methylation status of the feline catus satellite DNA region in the somatic cells of cloned cats and domestic normal cats by using a bisulfite sequencing method. Satellite sequences are heavily methylated in somatic cell chromosomes and are associated with dense heterochromatin where bundles of silent genes are wrapped up together. For the analysis of the cat satellite sequence, a 400-bp segment of the satellite genomic region, which has highly conserved 22 CpG sites, was amplified by PCR from bisulfite-treated genomic DNA, and the resulting PCR products were individually cloned and sequenced. For methylation analysis, genomic DNA was first isolated from somatic and placental cells of cloned and domestic normal cats. The DNA methylation status of the satellite DNA region was not significantly different among donor (using NT) cells (70.6, 77.0, and 79.1% in Donors A, B, and C, respectively), somatic cells of cloned cats (88.9, 82.2, and 85.9% in cloned A-1, 2, and 3; 78.0% in cloned B-1; 88.1, 78.9, 80.3, 83.2, 74.6, and 82.3% in cloned C-1, 2, 3, 4, 5, and 6, all respectively), and domestic cats (88.0, 81.6, and 81.8% in NC 1, 2, and 3, respectively). Also, the DNA methylation status of satellite DNA regions in the placenta was significantly different between cloned cats (80.5, 76.7, and 76.8% in cloned C-2, 5, and 7, respectively) and normal domestic cats (64.2, 66.7, and 74.9% in NC 1, 2, and 3, respectively). In conclusion, all of the somatic cells were highly methylated. The methylation status of the somatic cells was not different among groups, but that of placental cells was significantly different. This work was supported by KOSEF (Grant ? M10525010001-05N2501-00110).

Sequence analysis of feline caliciviruses isolated from the oral cavity of clinically normal domestic cats (Felis catus) in Florida

Four isolates (7μ3 per cent) of feline calicivirus (FCV), from oropharyngeal swabs taken from 55 unvaccinated apparently healthy cats, were identified by electron microscopy and reverse transcription-polymerase chain reaction (RT-PCR).A 671-bp fragment, comprising part of region B, all of regions C, D, and E and part of region F of theFCV capsid protein gene, was amplified from each isolate by RT-PCR and cloned for sequence analysis. Amino acid sequence comparison of these regions revealed significant sequence divergence from the F9 vaccine strain within regions C, E, and F. The hypervariable region E of the four Florida isolates and the NADC isolate contained three fewer amino acids than the commonly used F9 vaccine strain. This work provides support to the idea that currently circulating FCV strains may differ substantially from presently used vaccine strains.

Physiology of oropharyngeal swallow in the cat: a videofluoroscopic and electromyographic study.

The majority of animal studies of deglutition have examined electrically stimulated swallows in sedated animals. This present investigation examined oropharyngeal and cervical esophageal swallow physiology in three awake normal domestic cats using concurrent electromyography (EMG) and videofluorography (VFG). Hooked wire electrodes were surgically implanted into six oropharyngeal muscles in each cat. During collection of VFG and EMG data, each cat ate barium-impregnated cat food while the fluorography tube focused on a lateral view of the oral cavity, pharynx, and cervical esophagus. A number of significant differences in the physiology of swallowing were found between the cat and human adult. The oral stage of swallow is much longer in the cat with bolus accumulation in the valleculae. Duration and components of the pharyngeal stage of swallow are much faster, and the pharyngeal stage occurs earlier in relation to bolus passage through the cricopharyngeus. In addition, the cat exhibits a marked superior constrictor bulge at the onset of the pharyngeal contractile wave and summation of the peristaltic waves in the esophagus, whereas the human adult does not. Feline swallow physiology is more similar to that of the human infant than that of human adults.

Folate-sensitive and aphidicolin-inducible fragile sites are expressed in the genome of the domestic cat

Peripheral blood lymphocytes from three clinically normal domestic cats were cultured for folate-sensitive and aphidicolin-inducible fragile site expression. Induction of folate-sensitive fragile sites was accomplished by culturing cells with trimethoprim plus caffeine. Chromosomes from all cats expressed both folate-sensitive and aphidicolin-inducible breaks and gaps. There were no significant differences between the two methods of fragile site induction in the percentage of cells expressing chromosome breaks and gaps or the mean number of breaks and gaps per cell. All three cats expressed specific chromosome breaks resembling fragile sites at A1q21–22, A1p22, and B1q32. All three sites were induced by aphidicolin. The sites at A1q21–22 and B1q32 were also induced in folate-deficient medium. This is the first report of the induction of chromosomal fragile sites in a feline species.

The arthus reaction in domestic cats

A classic Arthus reaction was elicited in normal domestic cats using chicken red blood cells as antigen. The response was quantitated grossly by measuring the area of the resulting skin bleb at several set time intervals and by microscopic examination of biopsies taken at the conclusion of each of the trials. This method produced an intense Arthus reaction in each of the cats tested.

Histochemical studies on the inferior oblique muscle of Siamese cats and domestic cats with unilateral lid suture

Eye muscles of Siamese cats and monocularly lid sutured domestic cats have been shown to contract slower and fatigue quicker than eye muscles of normal domestic cats. The structural correlates to these functional differences were explored with histochemical techniques in the same muscles that were studied physiologically. Sections were stained for myosine ATPase and succinic dehydrogenese (SDH). The muscles of Siamese cats were smaller in cross-sectional area than muscles of ordinary cats. The proportions of type I, and type II and II C fibers were the same in all animals. In Siamese cats fibers of all types, and in domestic lid sutured animals type II fibers were smaller than corresponding types in normal cats. No differences could be detected between animals with respect to SDH staining properties. The capillary density per fiber was significantly lower in lid sutured domestic cats and Siamese cats than in normal cats. These changes in muscle and fiber area, and in capillary density are probably the morphological correlates to the observed functional differences. It has been suggested that they are related to deficiencies in visual function, particularly in binocular vision; they might represent muscular adaptation to reduced demands for fusional vergence movements in Siamese and lid sutured domestic cats, and for saccadic activity in Siamese cats.