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PubMed1978

Chronic asymmetry in the extraocular muscles of adult cats: stability in binocularity of cortical neurons.

During the first 2 weeks following unilateral severance of the 6 extraocular eye muscles in adult cats, the operated eye is partially immobile as shown by electrooculographic (EOG) recordings of horizontal eye movements. Although the motility of the operated eye improves with time (mainly in terms of amplitude but also with regard to direction and frequency of movements), it does not reach (up to 2 months) the level of the normal eye. Unit recording was done in visual cortex area 17 of these cats while paralyzed, either immediately (acute group, 5 cats), or 3-60 days (chronic group, 6 cats) following the operation. The number of visually inactive cells was slightly higher in the operated cats (13.8%) than in normal cats (8.3%), but the number of nonoriented cells or cells with disorganized receptive fields was similar in both groups of cats. The proportion of binocularly activated cells in the operated cats, especially in the chronic group (greater than 10 days after the operation, 71.2% of 153 cells), was similar to that of the normal control cats (72.8% of 236 cells). No ocular dominance shift was found when either the operated eye was compared to the normal one or the ipsilateral eye to the contralateral one. It was concluded that distortion of afferent proprioceptive input from the extraocular eye muscles to visual centers has no effect on binocularity of cortical neurons in adult cats.

Animals↗
PubMed1998

Neuroplasticity in the cat's visual system. Origin, termination, expansion, and increased coupling of the retino-geniculo-middle suprasylvian visual pathway following early ablations of areas 17 and 18.

We used anterograde and retrograde transsynaptic pathway tracing techniques to reveal the retinal origin and the cortical termination of the expanded retino-geniculo-middle suprasylvian (MS) cortex pathway in adult cats which sustained lesions of areas 17 and 18 on the day of birth (P1) or at 1 month of age (P28). Following anterograde transsynaptic transport of tritiated amino acids from the eye, four major results were obtained: (1) a strong and specific pathway from retina through dorsal lateral geniculate nucleus (dLGN) to the posterior half of MS cortex was identified; this pathway is a substantial expansion of an insignificant pathway present in intact cats; (2) the terminus of the pathway was lower layer III and layer IV; (3) contralateral projections were stronger than ipsilateral projections; (4) projections in P28 cats were stronger than those in P1 cats. Following retrograde transsynaptic transport of WGA-HRP from posterior MS cortex, four additional results were obtained: (1) the pathway was enlarged and visuotopically organized; (2) the pathway arose primarily from alpha- and gamma-retinal ganglion cells; (3) a small number of beta-cells in P1 cats and a modest number in P28 cats also contribute to the pathway; (4) the combined numbers of gamma- and beta-cells relative to alpha-cells was greater in temporal retina than in nasal retina. The combined demonstration of both origin and terminus of the pathway with transsynaptic tracers argued strongly for high levels of coupling between primary and secondary pathway limbs in both P1 and P28 cats. This level of coupling, as well as other features of the pathway, have much in common with the retino-geniculo-17/18 pathway of intact cats. However, the retino-geniculo-MS system in P1 cats transmits primarily Y and W signals, in P28 cats X, Y, and W signals; whereas the retino-geniculo-17/18 pathway transmits primarily X and Y signals. These results have implications for understanding the repercussions of early visual cortex lesions in monkeys and humans.

Amino Acids↗
PubMed2005

Duration of cats' (Felis catus) working memory for disappearing objects.

This study explored the duration of cats' working memory for hidden objects. Twenty-four cats were equally divided into four groups, which differed according to the type of visual cues displayed on and/or around the hiding boxes. During eight sessions, the four groups of cats were trained to locate a desirable object hidden behind one of the four boxes placed in front of them. Then, the cats were tested with retention intervals of 0, 10, 30 and 60 s. Results revealed no significant differences between the groups during training or testing. In testing, the cats' accuracy to locate the hidden object rapidly declined between 0 and 30 s but remained higher than chance with delays of up to 60 s. The analysis of errors also indicated that the cats searched as a function of the proximity of the target box and were not subjected to intertrial proactive interference. This experiment reveals that the duration of cats' working memory for disappearing objects is limited and the visual cues displayed on and/or around the boxes do not help the cats to memorize a hiding position. In discussion, we explore why the duration of cats' working memory for disappearing objects rapidly declined and compare these finding with those from domestic dogs. The irrelevance of visual cues displayed on and around the hiding boxes on cats' retention capacity is also discussed.

Animals↗
PubMed1975

Visual discrimination between spatially separated stimuli by cats with lesions of the superior colliculus-pretectum.

(1) This study was designed to test the ability of cats with lesions of the superior colliculus-pretectum to discriminate between stimuli which are widely separated in space. (2) Intact cats and cats learning or relearning after lesions of the superior colliculus-pretectum, were trained on light-dark (LD) and horizontal-vertical stripe (HV) discriminations in a V-maze, where the stimuli were widely separated in space, or in a divided straight maze, where the stimuli were side by side. (3) Two types of errors were scored: door-push errors when the cat pushed open the incorrect door; alley-entrance errors when the cat entered the incorrect alley, but turned and entered the correct alley without having pushed the incorrect door. (4) In the V-maze as well as in the straight maze, cats with lesions of the superior colliculus-pretectum achieved criterional performance by alley-entrance and door-push scoring on LD and HV discriminations. Thus, cats with lesions of the superior colliculus-pretectum can locate or orient to widely separated visual stimuli well enough to discriminate between them from a distant choicepoint. (5) Cats with lesions of the superior colliculus-pretectum generally committed a larger number and higher percentage of alley-entrance errors during learning than unoperated cats in either maze. However, commission of alley-entrance errors was not further increased in the V-maze, where the stimuli were widely separated in space. (6) All unoperated cats committed alley-entrance errors as well as door-push errors suggesting that commission of alley-entrance errors may reflect a normal process in two-choice learning.

Animals↗
PubMed1988

Alterations of group Ia-motoneuron monosynaptic EPSPs in aged cats.

The fashion in which the aging process affects synaptic transmission was explored in old cats. The synapses between Ia-afferent fibers and spinal cord alpha-motoneurons were studied employing intracellular recording techniques. The amplitude and time course of Ia-motoneuron monosynaptic excitatory postsynaptic potentials (Ia-EPSPs) recorded from motoneurons of the gastrocnemius medialis motor pool were determined in adult (1-3 years of age) and in old (14-15 years of age) cats. These Ia-EPSPs were evoked by the stimulation of the gastrocnemius medialis nerve in pentobarbital-anesthetized cats. No statistically significant change was found in the amplitude of these synaptic potentials in the old cats compared with the adult controls. In contrast, their time course was markedly modified; both rise-time and half-width were significantly longer in the old cats. In addition, the rate-of-rise of these Ia-EPSPs was significantly slower in the old cats. No breaks or inflections were observed on the rising phase of the potentials in the adult cats, whereas they were present in a subpopulation of potentials in the old cats. There was also a reduction, in the old cats, in the conduction velocity of the peripheral portion of the Ia-afferent fibers. These data indicate that Ia synaptic transmission is considerably affected during old age. It is suggested that these effects in aged cats may be due to modifications in presynaptic as well as postsynaptic processes.

Aging↗
PubMed1990

The nervous control of gingival blood flow in cats.

The purpose of the present study was to investigate the nervous control of gingival blood flow in cats. Gingival blood flow was measured by laser Doppler flowmeter in 75 cats during electrical stimulation and cutting or ligation of the inferior alveolar nerve and cervical sympathetic nerve without sympathectomy or pretreatment with adrenoceptor blocking agents. Three different patterns of responses in gingival blood flow were observed following electrical stimulation of the inferior alveolar nerve in cats. In 45 cats there was an increase in blood flow, in 4 cats a decrease in blood flow, and in 7 cats a biphasic change consisting of an initial decrease and a successive increase in blood flow. The vasodilator effect was significantly reduced by pretreatment with (D-Pro2, D-Trp7.9)-substance P. tripelennamine, and methysergide. Pretreatment with cimetidine, atropine, hexamethonium, phentolamine, or propranolol had no effect on vasodilatation. The vasoconstrictor response was completely inhibited by pretreatment with phentolamine; in this case the vasodilator response appeared after stimulation of the inferior alveolar nerve. Ligation or cutting of the inferior alveolar nerve always elicited an increase in gingival blood flow. Cutting the cervical sympathetic nerve had no effect on gingival blood flow in 8 of 10 cats and caused an increase in gingival blood flow in 2 cats; however, electrical stimulation of the cervical sympathetic nerve always caused a decrease in gingival blood flow in the cats investigated. The present results suggest that cat gingival blood flow is controlled by sympathetic alpha-adrenergic fibers for vasoconstriction and by sensory fibers and mast cells for vasodilatation.

Animals↗
PubMed1986

Immunotherapy with cat- and dog-dander extracts. III. Allergen-specific immunoglobulin responses in a 1-year double-blind placebo study.

An investigation was made of the specific antibody response to individual antigens in 40 patients taking part in a double-blind placebo study of immunotherapy with cat- or dog-dander extracts. Antigen-specific IgE levels were measured by means of CRIE, and the results were expressed as scores. The patients demonstrated IgE specificities toward 1 to 5 antigens. Cat-dander antigens Nos. 4 (cat Ag 1) and 7, and dog antigens Nos. 6 and 13, produced the highest scores, but high IgE binding was also found for dog albumin. After 1 year of treatment, the IgE responses of the two treatment groups (allergen and placebo) were statistically indistinguishable from those before the start of treatment. There was a tendency toward a reduction in score for two of the dander antigens (cat Ag 1 and dog Ag No. 13), and no new IgE specificities appeared. Antigen-specific IgG levels were measured by means of CIE with patient serum incorporated in an intermediate gel, and the results were expressed as plus/minus precipitins. Only two patients had precipitating antibodies before the start of treatment (one against cat albumin and one against cat Ag 1). During the course of treatment, the production of antigen-specific IgGs was observed in 18/22 allergen- and 1/18 placebo-treated patients. For the cat allergen-treated group, the specificities were directed against cat antigens Nos. 2, 3 (cat albumin), 4 (cat Ag 1), and 7, and for the dog allergen-treated group, against dog antigens Nos. 2 (dog albumin), 13, and 20.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Interaction of acute feline herpesvirus-1 and chronic feline immunodeficiency virus infections in experimentally infected specific pathogen free cats.

Cats with or without chronic feline immunodeficiency virus (FIV) infection were exposed to feline herpesvirus, type 1 (FHV-1). FIV infected cats became sicker than non-FIV infected cats and required more supportive treatment. However, there were no differences in the length of their illness or in the levels and duration of FHV-1 shedding. FHV-1 infection caused a transient neutrophilia at Day 7 with a rapid return to preinfection levels. The neutrophilia coincided with a transient lymphopenia that was accompanied by a decline in both CD4+ and CD8+ T-lymphocytes. A brief decrease in the CD4+/CD8+ T-lymphocyte ratio occurred at Day 14 in both FIV infected and non-infected cats. This decrease was mainly the result of an absolute and transient increase in CD8+ T-lymphocytes. CD4+ and CD8+ T-lymphocyte numbers and CD4+/CD8+ T-lymphocyte ratios returned to baseline within 4-8 weeks in both FIV infected and non-infected cats. FIV infected cats produced less FHV-1 neutralizing antibodies during the first 3 weeks of infection than non-FIV infected animals. The IgM FHV-1 antibody response was depressed in FIV infected cats whereas the IgG antibody response was unaffected. FHV-1 infection evoked a comparable transient loss of lymphocyte blastogenic responses to concanavalin A and pokeweed mitogen in both FIV infected and non-infected cats. However, response to pokeweed mitogen took longer to return to normal in FIV infected animals. Lymphocytes from FIV infected cats had a greater and more sustained proliferative response to FHV-1 antigen than non-FIV infected cats. The ongoing IgG antibody response to FIV was not affected by FHV-1 infection.

Acute Disease↗
PubMed1986

Response properties of single units in the accessory optic system of the dark-reared cat.

The visual responses of single units in the lateral and dorsal terminal nuclei (LTN and DTN) of the accessory optic system (AOS) were studied in adult cats reared in total darkness. In the LTN of the normal cat equal numbers of cells prefer upward and downward vertical stimulus motion (previous results). While direction selectively continued to be a characteristic property of LTN and DTN units in dark-reared animals, the distribution of preferred and non-preferred directions of LTN cells was radically altered such that almost every LTN cell examined in the dark-reared cat preferred downward stimulus motion. In contrast, the distribution of preferred directions among DTN cells was largely unaffected by dark rearing. Both normal and dark-reared cat DTN cells responded best to stimuli moving horizontally toward the recorded hemisphere. The velocity preferences of DTN units of the dark-reared cat were, however, much slower than those of normal DTN units. LTN units responding to downward motion in dark-reared cats showed similar velocity preferences to those downward direction-selective LTN units in normal animals. Unlike the highly binocular responses of AOS cells encountered in the normal cat, the ocular dominance distribution obtained from units in the LTN and DTN of the dark-reared cat is completely monocular, favoring the contralateral eye. Thus, dark rearing renders the distribution of preferred directions most affected in the LTN, velocity preference most affected in the DTN and ocular dominance strongly affected in both nuclei. The physiological response properties of the dark-reared cat presented in this report bear a close resemblance to those we have described in the AOS of acutely decorticated animals (previous results). Data obtained from the dark-reared cat support our earlier suggestion that the visual cortex is a major source of upward direction selectively, high-velocity tuning and ipsilateral eye input for AOS cells. Some of the functional consequences of these findings are discussed in relation to frontal eye placement and optokinetic nystagmus.

Animals↗
PubMed1987

Unilateral visual cortex deafferentation induces changes in receptive field properties of cortical cells in the intact hemisphere of normal and of monocularly deprived cats.

Receptive field properties and the selectivity of cortical cells to visual stimulation were studied in the visual cortices (the boundary between areas 17 and 18) of both hemispheres following unilateral deafferentation in normal and in early monocularly deprived cats. Almost no visual activity was encountered in the deafferented hemisphere and a considerable diminution in visual responsiveness was found in the intact hemisphere of all experimental cats. Responsiveness had increased with recovery time; unresponsive cells had consisted 44.6% of the cells in the intact hemisphere of the acute, 34.7% in the 3-month chronic and 14.5% in the normal cats. Disregarding the bias due to an early monocular deprivation, the ocular dominance distribution of the cells in the intact hemispheres of these cats was unaffected. Selectivity was markedly reduced in the intact hemisphere of the deafferented cats as expressed mainly in the increased orientation tuning range and in the proportion of orientation-selective cells. The proportion of these cells was 45.5% in the deafferented cats, 38.6% in the deafferented monocularly deprived cats, 65.3% in the monocularly deprived and 81.9% in the normal control cats. A similar trend, although less prominent, was found in respect to the proportion of direction-selective cells. The size of receptive fields was only slightly affected in the deafferented deprived cats. Receptive fields were considerably larger in size (length) in the deafferented cats in comparison to their respective normal and monocularly deprived controls. It is concluded that the absence of visual input from the deafferented hemisphere is bidirectionally affecting the corpus callosum.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1989

Consequences of visual deprivation in the absence of binocular competitive mechanisms in Siamese cat area 17.

The Siamese cat is a mutant with abnormally crossed visual pathways, which provides a model for studying the effects of visual deprivation in the absence of binocular competitive interactions. Siamese cats are known to be resistant to the effects of monocular eyelid suture. To further explore the nature of this resistance, the receptive field properties of neurons in area 17 of monocularly (MD) and binocularly (BD) deprived Siamese cats were studied. Neither condition produced a loss of cortical responsiveness, which is a characteristic result of binocular deprivation in normally pigmented cats. Somewhat more units in the deprived hemisphere of MD Siamese cats were orientation-selective, and many more units were direction-selective than in BD Siamese cats. This difference may be due to an effect of visual attentional mechanisms, which can function in MD but not BD Siamese cats. To test whether the resistance to the effects of visual deprivation in Siamese cats might be a more general phenomenon. Siamese and normally pigmented cats were raised in an 8-Hz stroboscopically illuminated environment. Both groups showed a severe loss of direction selectivity. Some of the normally pigmented cats also showed a loss of binocularity, which appeared to be secondary to strabismus.

Animals↗
PubMed1982

The contribution of the corpus callosum to receptive fields in the lateral suprasylvian visual areas of the cat.

In both ordinary cats and 'Boston' Siamese cats the visual areas in the lateral parts of the middle and posterior suprasylvian gyri (LSA) contain an extensive representation of the ipsilateral half of the visual field. In addition, in both groups of cats the overwhelming majority of neurons in LSA can be driven from both eyes. In Siamese cats this binocular interaction is in marked contrast with what is found in area 17 where neurons are almost exclusively activated through the contralateral eye. Transection of the posterior 1/3 to 1/2 of the corpus callosum had a different effect on the physiological organization of LSA in the two types of cats. In ordinary cats it caused the loss of the ipsilateral hemifield representation in the eye ipsilateral to the side of recording and reduced this representation in the other eye. However, after the section of the corpus callosum LSA neurons remained binocular. In Siamese cats the callosal transection left the representation of the ipsilateral hemifield in LSA unaffected, both totally abolished the input from the ipsilateral eye. These findings suggest that the visual callosal input to LSA has a different functional significance in ordinary and Siamese cats. In the former cats it may be related to perceptual equivalence across the vertical meridian of the visual field, whereas in the latter cats it may subserve interocular equivalence.

Animals↗
PubMed1986

Recovery of functions after neonatal or adult hemispherectomy in cats. III. Complex functions: open field exploration, social interactions, maze and holeboard performances.

Complex behavioral patterns were studied in cats with removal of the entire left cerebral hemisphere either as neonates (n = 10) or adults (n = 11), and in intact control cats (n = 24). Adult-lesioned cats showed decreased open field activity in locomotion, rearing and sniffing. Lesioned kittens showed similar deficits at 100 days of age, but by 150 days of age they resembled normal littermates in all 3 measures. In the presence of another cat, adult-hemispherectomized cats violated species-typical body-buffer space, approaching and attacking other cats. By comparison, normal cats never attacked and seldom approached in the open field. Neonatal-lesioned adults showed only occasional approach and a tendency to sit or stiff-walk in the presence of other cats; attacks were rare. Adult-lesioned cats responded poorly to reversal training for preferred arm of a T-maze, whereas neonatal-lesioned adults were significantly more trainable. Similarly, adult-lesioned cats exhibited a search deficit in a baited holeboard, while neonatal-lesioned adults searched normally. Overall, these results demonstrate that in this animal model, enhanced recovery following early vs adult lesions can also be found in relatively complex, spontaneous behavioral responses not previously studied in this regard.

Aging↗
PubMed1987

Movements of cats on a rotating cylinder: role of the substantia nigra pars reticulata and the deeper layers of the superior colliculus.

Recently it has been shown that the substantia nigra pars reticulata (SNR) is required for adjusting the body position. In this study the role of the SNR in the execution of movements was investigated. Therefore, the effects of bilateral SNR injections of picrotoxin (500 ng/0.5 microliter) and muscimol (200 ng/1 microliter) were investigated on movements of cats which were trained to cross a rotating cylinder. SNR injection of picrotoxin suppressed the movements that were executed by cats injected with distilled water (0.5 microliter), i.e. 'normal movements'. While crossing the rotating cylinder, picrotoxin-injected cats mainly executed movements that almost never occurred in distilled water treated cats. Picrotoxin-injected cats executed 'special movements', i.e. forward locomotion in which the hindlimbs were affected, and 'counter-movements'. While executing the latter movements no forward locomotion occurred at all; the cats solely executed lateral fore- and hindlimb movements opposite to the direction in which the cylinder rotated. SNR application of muscimol enhanced the execution of 'normal movements'. Since the SNR sends information to the deeper layers of the superior colliculus (dl-SC) via GABAergic fibers, it was also investigated whether pharmacological stimulation (muscimol) and inhibition (picrotoxin) of the GABAergic dl-SC activity affected these movements on the rotating cylinder: no changes were observed after injecting otherwise effective doses of muscimol (75 ng/1 microliter) and picrotoxin (100 ng/0.5 microliter). In order to compare the function of the SNR and dl-SC in programming a different type of movements, the effects of GABAergic agents in the dl-SC (picrotoxin 100 ng/0.5 microliter and muscimol 75 ng/1 microliter) and the SNR (picrotoxin 500 ng/0.5 microliter and muscimol 200 ng/1 microliter) were investigated on the feline ability to execute goal-directed movements in an experimental set-up that prevented the occurrence of targeting movements which were continuously guided by external, i.e. auditory, visual, tactile and olfactory stimuli. For that purpose cats were trained to step out of a startbox on a rotating cylinder, i.e. the target. Dl-SC injection of muscimol or SNR application of picrotoxin prevented the cats from stepping out of the startbox on the rotating cylinder. In contrast, cats injected with muscimol into the SNR or picrotoxin into the dl-SC stepped out of the startbox, although dl-SC application of picrotoxin elicited forelimb misplacements: frequently the cats placed their forelimbs alongside of, but not on the cylinder when trying to leave the startbox.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

The ocular dominance and receptive field properties of visual cortex cells of cats following long-term transection of the optic chiasm and monocular deprivation during adulthood.

Plasticity-induced interhemispheric transfer of visual information to cortical cells was studied in adult cats. The direct contralateral visual pathway was surgically eliminated permitting binocularity only by callosal transfer. In order to enhance the interhemispheric transfer, one hemisphere was made less visually active by depriving it chronically from visual input. Single cell recording was made in areas 17-18 boundary, the callosal projection zone, of operated (OC), operated and deprived (OCMD), and normal control cats. In the OCMD cats, greater than 90% of the cells in each hemisphere reacted ipsilaterally to the deprived or non-deprived eye. Only 3.1% of the cells in both hemispheres of the OCMD cats and 3.9% in the OC cats had contralateral input via the corpus callosum. The two hemispheres were similar in the selectivity of their cells to stimulus orientation and direction. The average receptive field area of the OCMD cats was also similar for the ipsilaterally driven cells in the two hemispheres; it was 1.2 degrees 2 for the deprived eye and 1.1 degrees 2 for the normal eye. The receptive fields (greater than 95%) of both eyes of the OCMD cats were found in the nasal visual hemifields and greater than 70% of them were at eccentricities of less than 5 degrees from the vertical meridian. The disappearance of the temporal (contralateral) hemifields in these cats and the physiological properties of their cortical cells were determined merely by the chiasm transection which had thus induced nearly complete interhemispheric separation. No effect of the monocular deprivation, in normal adult cats or in cats with chiasm transection was found, even after long periods (greater than 7 months). Therefore, plasticity-induced interhemispheric transfer of visual information was not found during adulthood.

Animals↗
PubMed1994

Visual hemispheric dominance induced in split brain cats during development: a model of deficient interhemispheric transfer derived from physiological evidence in single visual cortex cells.

The effects of cancellation of both interhemispheric callosal transfer and interocular interactions, were studied in early monocularly deprived cats. The main purpose of this study was therefore to prove whether unilateral hemispheric dominance would result under these conditions and to what extent each hemisphere will be functionally independent. Secondly, we have attempted to establish such an experimental model physiologically, on the single cell level. Interhemispheric transfer was surgically canceled by sagittal transection of the corpus callosum. In addition, the ocular projections were separated by sagittal transection of the optic chiasm in the transbuccal approach. This condition had practically induced visual split brain condition in these cats. These manipulations were carried out concurrently with monocular deprivation (SBDK group) which was surgically done by eye closure during the critical period of development of the visual system. Thus, the hemisphere ipsilaterally to the visually deprived eye had developed under conditions of deficient visual experience while the hemisphere ipsilaterally to the normal eye had developed under conditions of unaltered visual experience. A group of cats (SBK) similarly operated but equally binocularly exposed during development was served as controls. In addition, adult cats similarly operated during adulthood either chronically or acutely were studied to evaluate the effects of interhemispheric and interocular separation. Other groups of cats were also studied for comparison, and included sham operated and normal adult cats. At adulthood, electrophysiological studies were done on these cats, in which action potentials were extracellularly recorded from single cells in the visual cortex (area 17-18 boundary) following anesthesia and paralysis. Stimulation was carried out manually and by a computer driven optical system, presenting on a tangent screen light bars at various spatial positions, orientations and directions. Receptive fields were thus mapped for all neurons and their dimensions and eccentricities were measured. The responsiveness, ocular dominance and other parameters were also studied for these cells. The results in the early deprived cats and in their controls, had shown a full separation between the two hemispheres, as reflected in the almost absolute ipsilateral eye responsiveness (> 97.0% cells). In comparison, in the sham operated and in the normal control cats only minor proportions of cells (13.0-18.7%) have been found as ipsilaterally and monocularly driven, showing almost full interhemispheric and interocular interaction. The main difference, however, in the results between the early monocularly deprived cats and their controls is that in the first group the two hemispheres were asymmetric concerning the amount of visual activation and in the second one they were very symmetric.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Zidovudine toxicity to cats infected with feline leukemia virus.

Feline leukemia virus (FeLV) infection of cats is a model for the acquired immunodeficiency syndrome in humans. The toxicity of zidovudine was evaluated in SPF cats experimentally infected with FeLV. At initiation of the zidovudine study, all cats were antibody positive for FeLV antigens but clinically asymptomatic. Four cats were also viremic. Thirteen, 6- to 10-month-old cats were divided into five dosage groups and given zidovudine po at 0, 7.5, 15, 30, or 60 mg/kg daily in three equally divided doses for 32 to 34 days. Titers of circulating virus antigen remained constant; however, three of six cats receiving the higher doses of zidovudine (greater than or equal to 30 mg/kg) showed an increase in antibody titers to FeLV. Administration of zidovudine resulted in a progressive anemia, dependent upon dose and time. Macrocytes were observed prior to the development of anemia and were also found in several nonanemic cats. Repeated measures regression analyses indicated that an increased dose of zidovudine was associated with decreased packed cell volume, red blood cell count, and hemoglobin. As determined from the packed cell volume, the analyses indicate that anemia is induced only by the two highest doses of zidovudine. The regression model indicates that daily doses of 60 and 30 mg/kg are expected to induce anemia by Day 4 and Day 13, respectively. Progressive absolute neutropenia was observed in the greater than or equal to 30 mg/kg groups. Histopathologic lesions consisted of marked bone marrow hypercellularity in cats given greater than or equal to 30 mg/kg zidovudine and splenic extramedullary hematopoiesis in cats given greater than or equal to 15 mg/kg. Thus, oral toxicity of zidovudine in the cat is manifested by a dose-related anemia and neutropenia as observed in humans.

Anemia↗
PubMed2004

Airborne cat allergen reduction in classrooms that use special school clothing or ban pet ownership.

BACKGROUND: Allergens from furred animals are brought to school mainly via clothing of pet owners. Asthmatic children allergic to cat have more symptoms when attending a class with many cat owners, and some schools allocate specific resources to allergen avoidance measures. OBJECTIVE: The aim of the current study was to evaluate the effect of school clothing or pet owner-free classes compared with control classes on airborne cat allergen levels and to investigate attitudes and allergic symptoms among the children. METHODS: Allergen measurements were performed prospectively in 2 classes with school clothing, 1 class of children who were not pet owners, and 3 control classes during a 6-week period in 2 consecutive years. Portable pumps and petri dishes were used for collection of airborne cat allergen, and a roller was used for sampling on children's clothes. Cat allergen (Fel d 1) was analyzed with enzyme-linked immunoassay and immunostaining. Both years, questionnaires were administered to the children. RESULTS: We found 4-fold to 6-fold lower airborne cat allergen levels in intervention classes compared with control classes. Levels of cat allergen were 3-fold higher on clothing of cat owners than of children without cats in control classes. Pet ownership ban seemed less accepted than school clothing as an intervention measure. CONCLUSION: For the first time, it has been shown that levels of airborne cat allergen can be reduced by allergen avoidance measures at school by using school clothing or pet ownership ban, and that both measures are equally efficient. The clinical effect of these interventions remains to be evaluated.

Air↗