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At least 793 records · Page 44Linked to original sources
PubMed1998

Efficacy of oral administration of itraconazole to cats with dermatophytosis caused by Microsporum canis.

OBJECTIVE: To determine efficacy of orally administered itraconazole in cats with dermatophytosis caused by Microsporum canis. DESIGN: Uncontrolled clinical trial. ANIMALS: 15 cats with dermatophytosis caused by M canis. PROCEDURE: All cats were treated with itraconazole (1.5 to 3.0 mg/kg [0.7 to 1.4 mg/lb] of body weight, PO, q 24 h, for 15 days). Six cats had been treated with griseofulvin (10 mg/kg [4.5 mg/lb], PO, q 24 h) during a 60-day period, but their clinical condition had not improved. Five cats treated at the highest dosage of itraconazole vomited or became anorectic. Consequently, dosages were progressively decreased for each cat until adverse effects were not evident. After treatment, samples of hair were submitted for fungal cultures, and if appropriate, treatment was repeated when culture results were positive. RESULTS: 8 cats treated with itraconazole recovered completely, as indicated by resolution of lesions and negative results of fungal cultures. Six of these 8 cats received a single 15-day course of treatment, whereas the remaining 2 cats needed prolonged treatment (two 15-day courses of treatment and three 15-day courses of treatment). In 4 other cats that became clinically normal, M canis was isolated from hair samples obtained at the completion of treatment, even though only 1 colony or a small number of colonies was isolated. In the other 3 cats, itraconazole did not cause clinical improvement, and culture results remained positive. CLINICAL IMPLICATIONS: Oral administration of itraconazole at dosages of 1.5 to 3.0 mg/kg may be useful for the treatment of cats with dermatophytosis attributable to M canis infections.

Administration, Oral↗
PubMed1995

Overall pattern of callosal connections in visual cortex of normal and enucleated cats.

The effect of neonatal bilateral enucleation on the overall distribution of callosal connections in striate and extrastriate visual cortex of the cat was studied using tangential sections from the physically unfolded and flattened cortex. Callosal neurons were labeled by administering the anatomical tracer horseradish peroxidase directly to the transected corpus callosum. The pattern of callosal connections in binocularly enucleated cats showed both consistent differences and consistent similarities with the pattern in normal cats. In agreement with previous studies, it was found that callosal labeling at the 17/18 border of enucleated cats was considerably sparser than in normal cats. Moreover, we found that the strip containing the majority of labeled cells at the 17/18 border was narrower than in normal cats. In both normal and enucleated cats, scattered cells were distributed on either side of the 17/18 callosal strip, well into areas 17 and 18. In much of extrastriate cortex, the pattern of callosal connectivity in enucleated cats looked surprisingly normal. Details of the callosal pattern that were consistently found in normal cats could also be recognized in binocularly enucleated cats, such as two to four bridges of labeling spanning areas 18 and 19. Also, four zones that were free of callosal connectivity in area 7, on the banks of the suprasylvian sulcus, and in the posterior suprasylvian sulcus were found in both normal and enucleated cats. Finally, as in normal cats, dense cell labeling occurred on the crown of the suprasylvian gyrus at its posterior end, from which it extended laterally across both banks of the suprasylvian sulcus and into the fundus of this sulcus. The results of this study suggest that, although the stabilization of callosal connections at the 17/18 border region appears to depend on visual input, this input plays a less prominent role in the stabilization of callosal connections in extrastriate visual cortex.

Animals↗
PubMed1992

Antibody response and antibody affinity maturation in cats with experimental proliferative immune complex glomerulonephritis.

An experimental model of proliferative glomerulonephritis (GN) in the cat, which closely resembles human proliferative forms of GN, has been used to study the role of antibody and antibody affinity in the development of immune complex-mediated renal disease. The serum IgG and IgM antibody response to antigen, average antibody affinity (avidity) and affinity heterogeneity of the IgG and IgM populations was assessed at varying times after commencement of chronic immunization with the antigen, human serum albumin (HSA), by enzyme immunoassay. Cats could be classified according to whether they were "low", "intermediate" or "high" IgG responders, by quantification of serum IgG values. Cats with the lowest serum IgG values failed to develop glomerulonephritis. However, there was no relationship between actual IgG values and the severity of the induced disease. In contrast to IgG, there was no division of cats into low or high IgM anti-HSA responders. Again, cats with the lowest IgM values failed to develop GN, but, more interestingly, a late, marked increase in serum IgM anti-HSA occurred only in cats that developed clinical signs of GN (anterior uveitis and nephrotic syndrome). Maturation of average, functional IgG affinity (avidity) for HSA following chronic immunization was clearly demonstrated for all cats. At the end of the experiment, all cats had IgG of high affinity for HSA and the average affinity heterogeneity of the IgG populations was less than in measurements taken earlier. Values of IgG affinity at the end of the experiment were very similar both in cats which developed GN and in those which remained clinically, biochemically and pathologically normal. In contrast to IgG antibody, some cats developed IgM of increased affinity, whilst others produced antibody of reduced affinity, following chronic immunization. There was no correlation between the development of disease and the production of either low or high affinity IgM antibody. Data indicated that an alteration in IgM affinity occurred at a late stage, as serum IgM levels increased, in cats which progressed to develop GN. These findings suggested that an increase in both serum IgG and IgM anti-HSA values, in particular IgM, was associated with the development of a more severe immune complex renal disease in these cats. Although there was no evidence that differences in the average affinity of either the IgG or IgM antibody populations for HSA, were associated with the development of disease, the increase in IgM values was also accompanied by a concomitant alteration in IgM affinity for antigen.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1976

Biological bases for the integration of appetitive and consummatory grooming behaviors in the cat: a review.

Cats with pontile lesions, frontal neocortical lesions, and thyroidectomized cats display a dissociation of the appetitive and consummatory components of grooming behavior following tactile stimulation of the body surface, an abnormal behavior which waxes and wanes with the seasons of the year. Tryptophan hydroxylase activity and serotonin levels were significantly decreased in the superior colliculi (but not other brain regions) in cats with pontile lesions or frontal neocortical lesions, but not in thyroidectomized cats. Systemic administration of 5-hydroxytryptophan or monoamine oxidase inhibition plus tryptophan administration abolishes the abnormal grooming behavior in each group of cats, and microinjections of 5-hydroxytryptophan or serotonin into the superior colliculi has the same effect, indicating that the change in a serotonergic system is a critical aspect of the abnormal behavior in cats with lesions and that a serotonergic system may also be involved in the genesis of the abnormal grooming behavior in thyroidectomized cats. Functional inactivation of the serotonergic system by p-chlorophenylalanine, LSD, or serotonin receptor blockade does not induce the abnormal grooming behavior in normal cats, indicating that other factors are involved. Cats with lesions and thyroidectomized cats display a rhythmic dysfunction in the excretion of glucocorticoids and glucocorticoid administration abolishes the abnormal grooming behavior, suggesting that glucocorticoids are the other critical factor. Adrenalectomized cats do not display the abnormal grooming behavior, but when adrenalectomized cats are treated with p-chlorophenylalanine, the abnormal behavior appears. Thus, a serotonergic system in the superior colliculi, operating at some level of glucocorticoid function, is involved in the integration of appetitive and consummatory grooming behaviors.

5-Hydroxytryptophan↗
PubMed2005

Characterization of the Felix domesticus (cat) glaucoma-associated protein myocilin.

The domestic cat (Felix domesticus) is a useful model for understanding the implications of long-term expression and function of normal and mutant myocilin. To better understand the role myocilin has in the cat eye, we isolated and characterized cat myocilin. Oligonucleotides designed against conserved nucleotide regions of myocilin mammalian orthologs were used to PCR amplify a partial cat myocilin cDNA clone. Rapid amplification of cDNA ends (5' and 3' RACE) was used to obtain full-length cat myocilin. The 2125 nucleotide cat myocilin cDNA contains a 490 amino acid open reading frame. Comparison of cat myocilin to human myocilin shows a 87% similarity, including conservation of the N-terminal leucine zipper, N-linked glycosylation site, C-terminal olfactomedin domain, and all five cysteine residues thought to be involved in disulfide bond formation. Expression in a transformed human trabecular cell line or in Crandall feline kidney cells showed cat myocilin was secreted from these cells, similar to human myocilin, suggesting cat myocilin contains a functional signal peptide sequence. In contrast, expression of cat myocilin containing a known human glaucoma-associated mutation (Y423H in cat; Y437H in human) was not secreted. Characterization of cat myocilin will enable long-term studies be performed in Felix domesticus to analyze changes to intraocular pressure and the aqueous outflow pathway following expression of myocilin and glaucoma causing mutations.

Amino Acid Sequence↗
PubMed1997

Major cat and dog allergens share IgE epitopes.

BACKGROUND: Patients allergic to cats and dogs frequently display IgE reactivity against allergens from different animals, suggesting a cross-sensitization to common allergenic determinants. Although albumins have been recognized as relevant cross-reactive allergens, little is known regarding cross-reactive epitopes of the major cat and dog allergens. OBJECTIVE: In this study, sera from patients allergic to cats and/or dogs were used to investigate the presence of common IgE epitopes among the major cat and dog allergens. METHODS: The IgE reactivity profile of 109 patients who were allergic to allergens from several species of animals was determined with nitrocellulose-blotted cat and dog allergens. Sera from patients who were strongly allergic to the major cat and dog allergens were tested for the presence of cross-reactive IgE antibodies by one-dimensional and two-dimensional immunoblot inhibition experiments and by quantitative measurements obtained with the CAP-FEIA system (Pharmacia). RESULTS: Sixty-eight of 109 patients with animal allergy showed IgE reactivity to cat allergens and dog allergens. Sera from patients with both cat and dog allergy detected allergens of similar molecular weight in nitrocellulose-blotted cat and dog hair/dander extracts. Common, as well as species-restricted, IgE epitopes of the major cat and dog allergens could be demonstrated by IgE inhibition studies. CONCLUSION: Shared IgE epitopes of the major cat and dog allergens may provide an explanation for the clinical observation that allergies to cats and dogs are frequently associated.

Albumins↗
PubMed1992

Repeated infection of cats with Brugia pahangi: parasitological observations.

Cats were repeatedly inoculated with infective larvae of Brugia pahangi. On parasitological grounds they could be divided into 5 groups. Group I--most cats (some 70%) became microfilaraemic (mf+) and retained high levels of microfilariae (mf) in their blood for over 2 years. In some Group I cats mf counts stabilized at high levels whilst in others mf counts continued to increase. Large numbers of fecund adult worms were recovered from their lymphatics. Adult counts were not made on the cats in the current experiments but over 100 adults have been recovered from 'super-susceptible' cats. Large amounts of B. pahangi adult antigen were consistently present in the serum of all Group I cats. About 30% of cats became amicrofilaraemic (mf-). In these cats the peak mf levels were seldom above 10,000 mf/ml. Group II--these cats had less than 10,000 mf/ml and low antigen levels. After more than 1 year of being repeatedly infected B. pahangi adult antigen slowly declined and eventually could no longer be detected in their serum and the number of mf declined very slowly after the fall in antigen levels. This shows that in Group II cats the adult worms die and as the cats are resistant to the development of the continuing weekly inoculation of L3 no new adults can develop. Group III--these cats became mf--during the first year of infection but remained B. pahangi antigen-positive for many weeks after this and, at autopsy, had living adults in their lymphatics.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2003

A double-blind, placebo-controlled immunotherapy dose-response study with standardized cat extract.

BACKGROUND: Allergen immunotherapy with doses of cat extract containing approximately 15 microg of the major allergen, Fel d 1, have been proved clinically effective in several double-blind, placebo-controlled studies. However, the maintenance doses used in allergy practice in the United States are often considerably less than this proven dose. OBJECTIVE: The purpose of this investigation was to determine whether maintenance immunotherapy with cat dander extract containing 0.6 microg or 3.0 microg of Fel d 1 was more effective than placebo and similar in efficacy to treatment with extracts containing 15.0 microg Fel d 1, immunologic parameters being used as the outcome. METHODS: Twenty-eight cat-allergic patients were randomly entered, 7 in each group, into a double-blind, placebo-controlled comparison of the immunologic response to treatment with placebo or cat dander extract containing 0.6 microg, 3.0 microg, or 15.0 microg of Fel d 1. Maintenance doses were achieved in 8 visits over a period of 4 weeks through use of a cluster regimen; each subject then received 1 weekly maintenance injection before posttreatment measurements were made. The response to immunotherapy was assessed before immunotherapy and after the first weekly maintenance injection. Studies included responses to titrated skin prick tests to cat extract and an unrelated allergen and serum allergen-specific IgE and IgG4. Titrated nasal challenges were performed with cat extract; measurement of mRNA and secreted cytokines (IL-4, IL-5, and IFN-gamma) was done at 6 hours. Serum cytokines (IL-4, IL-5, IFN-gamma) were measured, and flow cytometric analysis of intracellular cytokines (IL-4, IL-5, IFN-gamma) was performed. Cat allergen-stimulated lymphocyte proliferation was performed with measurement of cytokines in the supernatant (IL-4, IL-5, IFN-gamma). RESULTS: All 28 subjects completed the study. Significant and dose-dependent differences were encountered in the titrated skin prick tests (P =.008), the cat-specific IgG(4) (P =.01), and the reduction in CD4+/IL-4+ PBMCs on flow cytometry (P =.03). There were no significant differences between placebo and cat dander extract containing Fel d 1 0.6 microg. Both extracts containing 3.0 microg and 15.0 microg produced significant decreases in skin prick test sensitivity (P =.02 and P =.002, respectively). The extracts containing 3.0 microg and 15.0 microg produced significant increases in cat-specific IgG4 (P =.01 and P =.006, respectively). Only the 15.0-microg-per-dose extract produced a significant reduction in the percent of CD4+/IL-4+ PBMCs (P =.003). CONCLUSION: In this double-blind, placebo-controlled study, a maintenance dose of cat dander extract containing 15.0 microg Fel d 1 produced the most consistent immunologic response. A dose of 3.0 microg reduced skin prick test sensitivity and increased cat-specific IgG4 but did not reduce the circulating CD4+/IL-4+ PBMCs, a change that is likely related to the clinically significant response to allergen immunotherapy. These findings suggest that a maintenance dose of 15.0 microg of Fel d 1 is most apt to be clinically effective for allergen immunotherapy.

Animals↗
PubMed1990

Effects of dietary acidification and potassium depletion on acid-base balance, mineral metabolism and renal function in adult cats.

Effects of dietary potassium restriction, with or without dietary acidification, on acid-base balance, mineral metabolism and renal function were evaluated in 12 adult cats. Six cats were fed a potassium-restricted diet (0.2% potassium) for 8 wk, and six cats were fed the same potassium-restricted diet plus a dietary acidifier (0.8% NH4Cl) for 8 wk. Both groups of cats were then fed the same diet supplemented with potassium gluconate (0.7% dietary potassium) for an additional 4 wk. Renal function was evaluated before treatment and again at 8 and 12 wk. Serum potassium concentration declined in all cats by wk 1 and was also lower in NH4Cl-treated cats at 2, 3, 6 and 8 wk than in control cats. Metabolic acidosis developed in both groups of cats. Dietary balance studies indicated negative potassium balance in NH4Cl-treated cats. Glomerular filtration rate declined significantly in NH4Cl-treated cats after 8 wk but was unchanged in control cats. From the results of this study, we conclude that adding a dietary acidifier to a potassium-restricted diet worsens hypokalemia, possibly by affecting gastrointestinal potassium handling, and induces severe metabolic acidosis and renal dysfunction in adult cats.

Acidosis, Renal Tubular↗
PubMed1992

Dietary protein source (soybean vs. casein) and taurine status affect kinetics of the enterohepatic circulation of taurocholic acid in cats.

The effect of dietary protein source (soybean vs. casein) and taurine status on kinetics of [24-14C] and [taurine-2-3H]taurocholic acid was determined by isotope dilution in 10 adult male cats (six taurine-replete and four taurine-depleted). Taurine-replete cats were fed 1500 mg taurine/kg purified diets containing either 435 g/kg casein (1500 Cas) or soybean protein (1500 Soy) in a crossover design. Taurine-depleted cats were fed the soybean protein diet with no taurine (0 Soy). Specific activity of [14C]- and [3H]taurocholic acid in bile was determined for 6 d following a pulse dose of dual-labeled taurocholic acid. Taurocholic acid pool size was significantly greater in cats when fed the 1500 Soy diet than when fed the 1500 Cas or than in cats fed the 0 Soy diet. Total entry rate, irreversible loss rate and recycling rate of [taurine-2-3H]taurocholic acid and the irreversible loss rate of [24-14C]taurocholic acid tended to be greater in cats when fed the 1500 Soy than the 1500 Cas diet. Irreversible loss rates of taurocholic acid in taurine-replete cats fed the 1500 Soy diet were significantly greater than in taurine-depleted cats, 356 vs. 120 mumol/d [24-14C]taurocholic acid and 445 vs. 56 mumol/d [taurine-2-3H]taurocholic acid. The fraction of taurocholic acid was greater, and the fraction of taurochenodeoxycholic and taurodeoxycholic acids lower in cats when fed the 1500 Soy than when fed the 1500 Cas diet. Taurine-depleted cats had less taurocholic, taurochenodeoxycholic, and taurodeoxycholic acids and greater glycocholic and cholic acids than taurine-replete cats fed the 1500 Soy diet. This study demonstrates that both dietary protein source and taurine status affect taurocholic acid kinetics and bile acid composition in cats.

Animals↗
PubMed1997

Progressive encephalopathy associated with CD4/CD8 inversion in adult FIV-infected cats.

Experimental intravenous challenge of five adult cats with the feline immunodeficiency virus Maryland isolate (FIV-MD) was investigated for its ability to induce neurologic abnormalities associated with the onset of immunodeficiency. Five 8-month-old cats were inoculated with 1000 median tissue culture infective dose of FIV-MD isolate, with five age-matched cats serving as uninfected controls. All FIV-MD-infected cats tested positive for serum antiviral antibodies and plasma viral DNA as detected by polymerase chain reaction at 2, 4, 10, and 16 months postinfection (PI). At 10 and 16 months PI, there was a significant reduction in the CD4/CD8 lymphocyte ratio, with all cats having a CD4/CD8 ratio of 1 or less. Total protein electrophoretic analysis of cerebrospinal fluid demonstrated a significantly increased albumin quotient at 4 and 16 months PI, representing a disrupted blood-brain barrier (BBB). At 16 months PI, all cats demonstrated a preferential increase in frontal cortical slow-wave activity compared with control cats. Serial evaluation of brainstem auditory evoked potential recordings revealed a prolongation of the interpeak latencies times over the study time. At least one abnormality was found over time in visual and somatosensory evoked potential testing in three and four infected cats, respectively. Comparing lymphocyte subtype ratios with neurologic testing revealed that every FIV-MD-infected cat exhibited an abnormality in at least one neurologic functional test with a concurrent CD4/CD8 count ratio of 1 or less. Overall, this study demonstrated that FIV-MD infection in adult cats results in a delayed-onset, progressive encephalopathy that parallels the decline in the CD4/CD8 lymphocyte ratio. Compared with prior information from pediatric FIV-MD-infected cats, these results indicate that age of infection influences the onset and severity of disease and may be associated with CD4 cell depletion in FIV-MD-infected cats, as seen in HIV-1-infected humans.

Analysis of Variance↗
PubMed1976

Allergens of mammalian origin V. Properties of extracts derived from the domestic cat.

Eight commercial cat dander extracts and two pelt extracts derived from mongrel and Siamese cats were compared. Cat allergn 1 and cat albumin were measured by radial immunodiffusion. Allergenic activity was evaluated by prick test and a modified radioallergosorbent test. In the latter, the dilution of each extract that produced 50% inhibition of binding of IgE antibodies to insolubilized cat allergen 1 (RAST 1) and insolubilized cat serum (RAST 2) was determind. The total non-dialysable solid content of the extracts did not correlate with any other parameter. Cat allergen 1 content determined by radial immunodiffusion correlated with average prick test results in ten cat-sensitive subjects and with RAST 1 activity. Cat albumin content correlated weakly with RAST 2 activity but not with any other measure of allergenic activity. Absorption of each extract with the gamma-globulin fraction of rabbit antiserum to cat allergen 1 significantly reduced prick test reactivity and RAST 1 activity, but not RAST 2 activity. These results indicate that cat allergen 1 is an important allergen in cat dander extracts and its measurement may be used to standardize the allergenic activity of such extracts.

Albumins↗
PubMed2003

High-dose exposure to cat is associated with clinical tolerance--a modified Th2 immune response?

BACKGROUND: Allergen-specific IgG4 antibodies, it is suggested, may be protecting against allergy development by blocking responses. Levels are proposed as a marker of modified Th2 response. OBJECTIVES: To assess the levels of IgE, IgG1 and IgG4 antibodies to cat in relation to cat exposure, asthma and allergic diseases. METHODS: We studied a population-based sample of 412 schoolchildren of 12-13 years of age. Parents of 402 children completed a questionnaire covering their child's medical history, the keeping of cats and other background data. Skin prick tests (SPTs) to common aeroallergens were performed in 371 of the children. Blood samples for the analyses of IgE, IgG1 and IgG4 antibodies were obtained from 309 of them. RESULTS: All children had an immune response to cat, predominantly of the IgG1 subclass. The levels of cat-specific IgG1 and IgG4, but not IgE, were high in children currently keeping a cat. Children with asthma had increased levels of cat-specific IgE and IgG1, and children with a positive SPT to cat also had increased IgG4. The presence of IgG4 was not associated with asthma or sensitization, unless there was a simultaneous production of IgE. Twenty-five percent of the children had an immune response with only IgG4, and no IgE antibodies to cat. This group of children had the highest frequency of cat-keeping, but a similar prevalence of asthma and allergy as those with neither IgE nor IgG4 antibodies to cat. CONCLUSION: Cat-keeping was associated with a modified Th2 response, producing IgG4 but not IgE antibodies. This immune response was not associated with an increased risk of asthma or allergy. However, the IgG4 antibodies did not directly mediate any protective effect.

Adolescent↗
PubMed1993

Toxicologic effects of ribavirin in cats.

Ribavirin, a broad-spectrum antiviral agent active in vitro against a number of RNA and DNA viruses, has been associated with moderate toxicity in laboratory animals and humans. Clinically, ribavirin has been used effectively in persons primarily to treat life-threatening viral diseases such as acute haemorrhagic fever or viral pneumonia of infants. In order to evaluate the feasibility of using this antiviral agent in cats, the effects of oral (p.o.), intramuscular (i.m.) and intravenous (i.v.) doses of ribavirin in 27 9-month-old specific-pathogen-free cats were evaluated by haematology, clinical chemistries, bone marrow biopsies and histopathology. Ribavirin was administered once daily for 10 consecutive days at a dose of either 11, 22, or 44 mg/kg after which all cats were euthanatized and necropsied. Most cats receiving 22 or 44 mg of ribavirin/kg became anorectic and suffered some degree of weight loss (0.2 to 0.6 kg), and about one-third of the cats developed diarrhoea and/or mucous membrane pallor. Icterus or haemorrhage was not observed. The most profound and consistent haematologic change, particularly among the moderate and high dosage groups regardless of route of administration, was a significant and severe thrombocytopenia (range, 33-78% reduction in mean platelet counts vs. baseline). Other changes, particularly reductions in total WBC and neutrophils and reductions in RBC and PCV, tended to occur at lower ribavirin dosages, but generally they were not statistically significant. Cats given 44 mg of ribavirin/kg i.v. showed significant decreases in leukocyte variables, including total WBC (P = 0.016), neutrophils (P = 0.026) and lymphocytes (P = 0.047). Mild-to-moderate increases in serum alanine aminotransferase and alkaline phosphatase activities occurred at doses of 22 and 44 mg/kg. Evaluation of bone marrow biopsies before and after treatment revealed that cats given 11 mg of ribavirin/kg had mild megakaryocytic (MK) hypoplasia, whereas cats receiving 22 or 44 mg/kg had progressively severe degrees of MK hypoplasia and dysplasia, asynchronous MK maturation, and increased myeloid:erythroid ratio. Pathologic changes in ribavirin-treated cats generally were mild and included primarily enteritis (seven cats) and hepatocellular vacuolation and/or centrilobular necrosis (seven cats). Results of this study in cats indicated that daily administration of ribavirin at a dose range of 11 to 44 mg/kg induced a dose-related toxic effect on bone marrow, primarily on megakaryocytes and erythroid precursors, and at the higher dosages is suppressed numbers of circulating leukocytes.

Administration, Oral↗
PubMed1994

Neuropathological changes following occlusion of the superior sagittal sinus and cerebral veins in the cat.

Superior sagittal sinuses (SSS) of 36 mongrel cats were occluded by polymer injection. Immediately prior to the occlusion, Evans-blue (EB) was administered intravenously. The cats were killed 1,3,6,12,24,72 and 120 h after sinus occlusion. Two sham-operated cats were killed 6 h and two 120 h after the operation. In 16 cats in which the occlusion was limited to the SSS, as well as in the sham-operated cats, no EB extravasation was present. However, ultrastructurally in two animals, the extracellular spaces were moderately enlarged, corresponding to increased permeability for water without opening of the BBB for proteins. In 20 cats in which cortical veins were occluded, in addition to the SSS, EB was extravasated. In nine of these cats, which had moderate oedema, EB-staining was present only in the cortex. In 11 cats with severe oedema, massive EB was extravasated. In nine of these cats, which had moderate oedema, EB-staining was present only in the cortex. In 11 cats with severe oedema, massive EB extravasation was observed also in the white matter. The U-fibre layer was free of EB, suggesting that the extension of oedema was blocked by this zone. Cats with severe oedema showed extensive haemorrhagic cerebral infarction widely, but not completely, overlapping with ischaemic necrosis, and corresponding to the differences in the territories of arterial supply and of venous drainage. Seven animals displayed haematomas in the parasagittal white matter. Electron microscopy (EM) showed damage to the endothelium of capillaries and venules with extravasation of platelets. In cats which survived longer than 24 h, the extracellular spaces were filled with proteinaceous transudate.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

Survey of predation by domestic cats.

OBJECTIVES: To calculate the proportion of house cats which were observed by their owners to have caught prey and to describe the characteristics of these cats. DESIGN AND PROCEDURE: A telephone questionnaire was administered to a randomly selected population of 458 cat owners in metropolitan Perth. Specific questions were asked about demographic characteristics, habits and diets of the cats, and whether the owners had observed their cats catch prey in the 12 month period preceding the survey. RESULTS: The owners of 36% of 644 cats had observed their cats with prey in the 12 month period preceding the survey. Cats which spent more time outside, were neutered, cross-bred, originated from households with only one or two cats or were not fed meat were significantly more likely to be observed to predate. The body condition and diet (other than feeding meat) of cats did not influence the reported frequency of predation. CONCLUSION: Although cats are only one factor involved in the reduction in the numbers and diversity of Australian wildlife, restriction of the outside activities of cats is likely to diminish predation, particularly in areas close to native vegetation.

Animals↗
PubMed1984

Critical periods for functional and anatomical compensation in lateral suprasylvian visual area following removal of visual cortex in cats.

Previous experiments have found that neurons in the cat's lateral suprasylvian (LS) visual area of cortex show functional compensation following removal of visual cortical areas 17, 18, and 19 on the day of birth. Correspondingly, an enhanced retino-thalamic pathway to LS cortex develops in these cats. The present experiments investigated the critical periods for these changes. Unilateral lesions of areas 17, 18, and 19 were made in cats ranging in age from 1 day postnatal to 26 wk. When the cats were adult, single-cell recordings were made from LS cortex ipsilateral to the lesion. In addition, transneuronal autoradiographic methods were used to trace the retino-thalamic projections to LS cortex in many of the same animals. Following lesions in 18- and 26-wk-old cats, there is a marked reduction in direction-selective LS cortex cells and an increase in cells that respond best to stationary flashing stimuli. These results are similar to those following visual cortex lesions in adult cats. In contrast, the percentages of cells with these properties are normal following lesions made from 1 day to 12 wk of age. Thus the critical period for development of direction selectivity and greater responses to moving than to stationary flashing stimuli in LS cortex following a visual cortex lesion ends between 12 and 18 wk of age. Following lesions in 26-wk-old cats, there is a decrease in the percentage of cells that respond to the ipsilateral eye, which is similar to results following visual cortex lesions in adult cats. However, ocular dominance is normal following lesions made from 1 day to 18 wk of age. Thus the critical period for development of responses to the ipsilateral eye following a lesion ends between 18 and 26 wk of age. Following visual cortex lesions in 2-, 4-, or 8-wk-old cats, about 30% of the LS cortex cells display orientation selectivity to elongated slits of light. In contrast, few or no cells display this property in normal adult cats, cats with lesions made on the day of birth, or cats with lesions made at 12 wk of age or later. Thus an anomalous property develops for many LS cells, and the critical period for this property begins later (between 1 day and 2 wk) and ends earlier (between 8 and 12 wk) than those for other properties.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1992

Dynamic range of neural rate responses in the ventral cochlear nucleus of awake cats.

1. Response thresholds and dynamic range properties of neurons in the ventral cochlear nucleus (VCN) of awake cats were measured by fitting a computational model to rate-level functions for best frequency (BF) tone bursts and for bursts of broad-band noise. Dynamic range measurements were performed in quiet and in the presence of continuous background noise. 2. The sample of neurons obtained in the VCN of awake cats exhibited a variety of peristimulus histograms (PSTHs) and thresholds. All PSTH response types previously described in the VCN of anesthetized cats were found in awake cats. The lowest thresholds for neural responses were observed at sound pressure levels that were equivalent to behavioral thresholds of absolute auditory sensitivity. 3. When responses to BF tones or bursts of broad-band noise were recorded in quiet backgrounds, the dynamic range properties of most units in the VCN of awake cats were not significantly different from dynamic range properties of auditory nerve fibers (ANFs) in anesthetized cats or VCN units in decerebrate cats. All auditory units showed a larger dynamic range for noise bursts than for tone bursts, but VCN units with primary-like and onset PSTHs showed larger dynamic ranges for responses to noise bursts than that of ANFs and VCN chopper units. 4. When tests were performed in the presence of continuous noise, rate-level functions for BF tone bursts shifted to higher tone levels and showed a more compressed range of driven rates in comparison with data obtained in quiet. Compression of the rate-level function in noise resulted from an increase in driven rate at low tone levels and a decrease in rate at high tone levels. These changes in the rate-level function suggest that noise may reduce the range of BF tone levels that are potentially encoded by a unit's rate responses. By exhibiting larger shifts and less compression in background noise, VCN units in awake cats better preserved the dynamic range of their rate responses to BF tones than ANFs in anesthetized cats or VCN units in decerebrate cats. 5. Rate-level functions were obtained from a small sample of VCN units not only with the cat performing the behavioral task but also with the cat awake and sitting quietly in the testing apparatus. No differences in noise-induced shift or compression were noted between the two testing conditions.(ABSTRACT TRUNCATED AT 400 WORDS)

Acoustic Stimulation↗