An estimation of the contrast sensitivity of kittens after termination of the critical developmental period

Special contrast sensitivity was estimated in kittens at the age of 6, 9 and 12 months as well as in adult cats. Acuteness of perception of grating pattern remained the same in kittens of 6 as well as 12 months of age. However, the former kittens were shown to have a decreased contrast sensitivity at lower spatial frequencies (cycles/degree). The contrast sensitivity reached the adult level at 12-month age. This seems to reflect a maturation of the higher cortical areas involved in the recognition process.     

Characterization of osteopenia in feline mucopolysaccharidosis VI and evaluation of bone marrow transplantation therapy

Studies on a feline model of MPS VI demonstrated a marked osteopenia in iliac crest bone samples from young adult animals with fewer, finer trabeculae. In the absence of significant differences in bone remodeling, this was considered due to defects in endochondral ossification and the formation of fewer trabeculae. Cell-level bone formation was normal despite the presence of vacuolated osteoblasts. Affected animals had vacuolated osteocytes in larger lacunae. Cats of the same age who had received a bone marrow transplant 12 months prior as young kittens, had significantly more trabecular bone with thicker trabeculae. The presence of smaller osteocyte lacunae in these animals as compared to their untreated MPS VI cats appeared to be a direct effect of bone marrow transplantation and a useful parameter to monitor its efficacy.     

Primary neural disorders in the deaf white cat cochlea

Eleven white kittens were investigated from 2 days after birth up to an age of 4 months. After their hearing ability or deafness had been tested electrophysiologically, electron microscopic work was done at the level of the cochlea. Previous histological data indicated that the hereditary process of degeneration begins at the epithelial and sensory elements of the cochlea, and that the neural degeneration is only a secondary and very slow process. Results presented here indicate that, at least in some white cats, this assumption needs to be modified. Early failure in the myelination of the lamina spiralis fibres was noticed in most of the white kittens. Furthermore, two kittens (7 and 16 days old) presented a complete degeneration of the spiral ganglion neurons, and signs of anterograde degeneration of their fibres going to the organ of Corti. These primary neural defects indicate that hereditary hearing defects may directly affect both epithelio-sensory and neural structures.     

Physiological studies of the precedence effect in the inferior colliculus of the kitten

The precedence effect (PE) is a perceptual phenomenon that reflects listeners' ability to suppress echoes in reverberant environments. The PE is not present at birth and appears only several months postnatal. Recent physiological studies have demonstrated correlates of the PE in the central nucleus of the inferior colliculus (ICC) of adult animals. The present study extended the same techniques to search for similar correlates in the ICC of kittens during the first postnatal month. Stimuli consisted of pairs of clicks or noise bursts presented from different locations in free field or with different inter-aural differences in time (ITD) under headphones, with an inter-stimulus-delay (ISD) between their onsets. Results suggest that a physiological correlate of the PE, i.e. suppression of responses to the second source, is present as early as 8 days postnatal, and occurs at similar ISDs to those recorded in adult cats. Suppression in kitten neurons varies with stimulus level, duration, and azimuthal position, in a similar manner to that in adult neurons. The age at which correlates of the PE in the kitten can be found precedes the age at which kittens can localize sound sources effectively, and presumably before the age at which they would demonstrate the PE behaviorally. Thus, the neural mechanisms that might be involved in the first stages of processing PE stimuli may be in place well before the behavioral correlate develops.     

Alkaline phosphatases in tissues and sera of cats

The numbers and widths of bands of alkaline phosphatase (ALP) activity in polyacrylamide gels and the comparison of their electrophoretic mobility to that of a reference substance (Rf value) were found to be reliable aids in the identificaiton of various isoenzymes in in serum and organ extracts from cats. The hepatic isoenzyme was identified in sera of clinically normal adult cats, pregnant cats late in gestation, and cats with common bile duct occlusion. In addition to the hepatic isoenzyme, placental ALP was found late in gestation in sera from queens. Sera from kittens less than 15 weeks of age contained only the osseous ALP isoenzyme.     

Development of contrast sensitivity and temporal-frequency selectivity in primate lateral geniculate nucleus

We studied the development of spatial contrast-sensitivity and temporal-frequency selectivity for neurons in the monkey lateral geniculate nucleus. During postnatal week 1, the spatial properties of P-cells and M-cells are hardly distinguishable, with low contrast-sensitivity, sluggish responses, and poor spatial resolution. The acuity of P-cells improves progressively until at least 8 months, but there is no obvious increase in their maximum contrast-sensitivity with age. The contrast sensitivity of M-cells is already clearly higher than that of P-cells by 2 months, and at 8 months of age this characteristic difference between M- and P-cells approaches the adult pattern. There is a major increase in responsiveness during the first 2 postnatal months, especially for M-cells, the peak firing rate of which rises fivefold, on average, between birth and 2 months. Many P-cells in the neonatal and 2-month-old animals did not give statistically reliable responses to achromatic gratings, even at the highest contrasts: this unresponsiveness of P-cells might result from low gain and/or chromatic opponency. The upper limit of temporal resolution in the neonate is low--about one-third of that in the adult. Among M-cells, the improvement in temporal resolution, like that in contrast sensitivity, is rapid over the first 2 months, followed by a slower change approaching the adult value by 8 months of age. The development of contrast sensitivity, responsiveness and temporal tuning are little affected, if at all, by binocular deprivation of pattern vision from birth for even a prolonged period.     

La plasticité du système calleux.

Studied the potential plasticity of the callosal system in epileptic patients and kittens subjected to corpus callosotomy. Human Ss were 5 male and female Canadian children, adolescents, and adults (epilepsy) (corpus callosotomy). Animal Ss were 6 cats (corpus callosotomy at 20 or 45 days after birth). Human Ss were tested for unilateral tactile discrimination of a series of 30 familiar objects presented randomly to the right or left hand and for interhemispheric transfer of tactile information about 30 objects that were manipulated inside of a box. The cats were tested for unilateral discrimination of visual patterns and interhemispheric transfer of these patterns. The cats were trained to recognize the patterns with 1 eye and tested with the other. The results of both studies were analyzed according to age at which corpus callosotomy had been performed on the cats. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental and food profiles of infants born to adolescent and adult mothers

OBJECTIVE: To compare developmental markers and dietary intake of infants born to lower socioeconomic adolescent and adult mothers. DESIGN: Sixty-one adolescent (age 14-18 years) and 60 adult (age 22-28 years) mothers met inclusion criteria of comparable socioeconomic status, age range, urban/rural residence, and distribution of infants by gender. SAMPLE/SETTING: Adolescent subjects were recruited in last trimester and adult mothers postpartum. Interviews were conducted when infants were about 6 and 12 months of age. Data included age of occurrence for eight markers, age at adding complementary foods, two 24-h dietary recalls, and two measurements of growth. RESULTS: Adolescent mothers reported a significantly earlier age at which the infant "holds a spoon by self" and "drinks alone from a trainer cup." Six other markers were not significantly different between groups. Adolescent mothers fed cereal significantly earlier than did adult mothers, but there were no significant differences for fruit, vegetables, and meat. At 12 months, infants of adolescents had intakes of vitamin D and iron which were < 100% of recommended allowances, as did infants of adult mothers for vitamin D, iron, and zinc. Dietary fat was significantly higher at 6 and 12 months and vitamin C was lower at 12 months for infants of adolescents compared to the adult group. CONCLUSIONS: Compared to adult mothers, adolescent mothers reported earlier mean ages for developmental markers related to self-feeding, and introduced cereal earlier. In each group, selected nutrient intakes decreased from recommended amounts in the 6-12-month period. Fat intakes were significantly different between groups at 6 and 12 months.     

31P NMR spectroscopy of erythrocytes in congenital hemolytic anemias: detection of heterogeneous erythrocyte populations and quantification of intracellular 2,3-diphosphoglycerate

We have measured the angle between the visual axis and the axis projected from the center of the optic disk in 35 cats ranging in age from two weeks to adulthood. Our results show that this angle, a, declines from around 27 degrees in very young kittens to about 16 degrees in adult cats, with most of the change occurring during the first 6 weeks after birth. We interpret this change as reflecting a progressive contraction of the area of object space projected onto the retina. For this to occur, the posterior nodal distance of the eye's optical system must increase by a larger factor than the transverse extent of the retina. This process undoubtedly contributes to maturation of the kitten's visual function, causing a reduction of the size of neuronal receptive fields and an enhancement of spatial resolution.     

A paradigm shift for acute myocardial infarction: from coronary patency to myocardial reperfusion

OBJECTIVE: To evaluate the safety and efficacy of amitriptyline hydrochloride in the treatment of severe recurrent idiopathic cystitis (IC) in cats. DESIGN: Prospective study. ANIMALS: 15 cats with IC that failed to respond to other treatments. PROCEDURE: Each cat received 10 mg of amitriptyline, PO, every 24 hours in the evening for 12 months or until signs recurred. Urinalysis, CBC, serum biochemical analysis, urine bacteriologic culture, and cystoscopy were performed initially, and after 6 and 12 months in responders. Severity scores of owner-observed signs of lower urinary tract (bladder and urethra) disease were recorded. RESULTS: During the first 6 months of treatment, 11 of the 15 cats had no owner-observed signs of lower urinary tract disease. During the next 6 months, 9 of 15 cats remained free of signs of cystitis. Despite clinical improvement, cystoscopic abnormalities persisted in all cats at the 6- and 12-month evaluations. Hematuria and proteinuria were decreased at the 12-month evaluation compared with the initial evaluation. Two of 15 cats initially appeared somnolent after amitriptyline treatment. Of 9 cats completing the study, 7 had increased body weight and 8 had decreased coat quality compared with the initial evaluations. Four cats developed small cystic calculi during the first 6 months of the study. Serum biochemical or hematologic abnormalities were not detected during the study. CLINICAL IMPLICATIONS: Amitriptyline treatment successfully decreased clinical signs of severe recurrent IC in 9 of 15 cats treated. Somnolence, weight gain, decreased grooming, and transient cystic calculi were observed during treatment in some cats.     

Neuromuscular blocking effects of aminoglycoside antibiotics on fast- and slow-contracting muscles of the cat

The neuromuscular-blocking effects of neomycin, streptomycin, and gentamicin were examined in fast- and slow-twitch muscles of pentobarbital-anesthetized cats. These antibiotics were more effective in reducing indirectly stimulated contractions of the gastrocnemius muscle than of the ipsilateral soleus muscle in adult cats. Respiratory-depressant effects of these antibiotics were more closely associated temporally with effects on soleus than on gastrocnemius twitch. Neomycin was a more potent neuromuscular blocking agent in kittens greater than 7 weeks old than in kittens less than 6 weeks old. Calcium ions were more effective in antagonizing the effects of neomycin on gastrocnemius than on soleus twitch; however, neostigmine was more effective in antagonizing the effects of neomycin on soleus than on gastrocnemius twitch. These data indicate a difference in responsiveness of fast- and slow-twitch muscles (fast greater than slow) to the neuromuscular-blocking effects of aminoglycoside antibiotics, and suggest that this may be related to a difference in the predominance of pre- and postjunctional inhibitory actions of these agents in the 2 muscle types.     

Polymorphism of feline beta-globins studied by reversed-phase high-performance liquid chromatography

OBJECTIVE: To characterize the feline beta-globin system with respect to the number and genetics of adult beta-globin chains. ANIMALS: 84 domestic and purebred cats (9 breeds), 14 cats were mildly to severely anemic. For genetic analyses, 12 litters with 1 to 5 offspring for a total of 29 kittens. PROCEDURE: Feline globins from erythrocyte lysates were separated by reversed-phase high-performance liquid chromatography and analyzed on the basis of retention time and area of each beta-globin peak. Mixing studies with half the amount of hemoglobin (Hb) from 2 cats were performed to assign the beta-globin peaks in each cat. The Hb from 60 cats were also separated by standard isoelectric focusing methods. RESULTS: Heme and alpha- and beta-globins were effectively separated by high-performance liquid chromatography. Although there was only 1 alpha-globin, a total of 6 beta-globins (I through VI) were identified, with each cat having 1 to 4 beta-globin chains. From analysis of the number of beta-globins, their relative amounts, and Hb mixing studies, 17 beta-globin patterns were observed. The beta-globin pattern in healthy and anemic cats was identical. Family studies documented an autosomal codominant mode of inheritance of the adult beta-globins and a linkage of 2 beta-chains forming haplotypes. CONCLUSIONS: Biochemical and genetic evidence for the greatest polymorphism of adult beta-globins thus far described in any species is provided. A feline beta-globin gene region with 2 linked beta-globin gene loci and 2 and 5 alleles is proposed. CLINICAL RELEVANCE: Better understanding of feline Hb will likely be helpful for diagnosis of hemoglobinopathies in anemic cats.     

Effects of early retinal lesions on conduction velocity relationships in the dorsal lateral geniculate nucleus of the cat

Bilateral retinal lesions have been made in and around the area centralis in 5 kittens 23-28 days of age. Twelve to 14 months later, microelectrode recordings were made in the LGN of these animals. Penetrations through the medial, deafferented portion of the nucleus encountered retinally innervated cells at the same rate as penetrations through the intact lateral half of the nucleus or through the LGN of normal adult cats. The correlation between orthodromic anc antidromic latency for LGN relay cells in experimental animals was reduced when compared to normal animals, and the percentage of cells receiving dual fast and slow retinal input was increased in experimental animals. These observations are interpreted as evidence that the medial portion of the LGN was reinnervated following the neonatal retinal lesions, and that the specificities that normally exist between relay cells and their retinal afferents in terms of axonal conduction velocity were not maintained during the course of this reinnervation.     

Feline immunodeficiency virus associated myopathy in the adult cat

Human immunodeficiency virus (HIV-1) associated myopathy can be a debilitating disease in humans, leading to weakness, myalgia, and muscle wasting. Subclinical neuromuscular involvement is also common. A range of histologic lesions have been described in both forms that include both inflammatory and degenerative changes. The purpose of this study was to determine whether a myopathy was present in adult cats experimentally infected with feline immunodeficiency virus (FIV). Six specific pathogen-free, laboratory-housed cats were challenged intravenously with 1000 TCID50 of the Maryland isolate of FIV (FIV-MD) at 8 months of age. The highest serum creatine kinase values were seen at 18 months postinfection (mean 9838, SD 4805 U/L) compared to preinfection (mean 950, SD 374 U/L). Needle EMG studies revealed abnormal spontaneous activity in 2 cats. All FIV-MD infected cats exhibited at least one abnormality in muscle pathology. Of the 24 muscle samples, 15 (63%) had histopathologic lesions. The predominant histologic abnormalities consisted of perivascular and pericapillary lymphocytic infiltration, and myofiber necrosis, phagocytosis, and regeneration. Lymphocytic infiltration was graded 2+ or higher in 12 of 24 muscle samples (0 = negligible; 4+ = extensive). Immunohistochemical phenotypic lymphocyte labeling in all cats demonstrated only CD8+ lymphocyte staining. This report demonstrates the presence of a FIV associated inflammatory myopathy in the adult cat. Several similarities are apparent in comparison to HIV-1 associated polymyositis reported in humans. Future studies in the cat may thus prove useful in elucidating the pathogenesis of retrovirus related myopathy in humans.     

Long-term effects of prenatal exposure to low levels of gamma rays on open-field activity in male mice

The open-field activity of first-generation (F1) hybrid male C57BL/6 x C3H mice irradiated with gamma rays on day 14 of gestation was studied at the following ages: 6-7 months (young), 12-13 months (adult) and 19-20 months (old). Doses were 0.5 Gy or 1.0 Gy. Open-field activity was recorded with a camera. The camera output signal was recorded every second through an A/D converter to a personal computer. The field was divided into 25 8-cm2 units. All recordings were continuous for 60 min. The walking speed of the 1.0-Gy group recorded at 19-20 months was higher than that for the comparably aged control group. The time which the irradiated group, recorded at 19-20 months, spent in the corner fields was high in comparison with the control group at the same age. Conversely, the time spent by the irradiated group in the middle fields when recorded at 19-20 months was shorter than in the comparably aged control group. No effect of radiation was shown for any of the behaviors observed and recorded at 6-7 and 12-13 months. The results demonstrate that such exposure to gamma rays on day 14 of gestation results in behavioral changes which occur at 19-20 months but not at 6-7 or 12-13 months.     

Cognitive development in kittens (Felis catus): A cross-sectional study of object permanence.

Administered tests of object permanence to 28-, 35-, 48-, and 150-day-old kittens (Felis catus) in order to assess as accurately as possible the developmental level reached at each age group in this Piagetian cognitive capacity. The results indicate that 28-day-old-kittens visually tracked a moving object in their perceptual field (Stage 2); 35-day-olds recovered a hidden object only if they had initiated a search movement at the time of disappearance (Stage 4a); 48- and 150-day-olds mastered multiple visible displacements (Stage 5b). The study showed that the upper limit, Stage 5b, observed in adult cats was reached by Day 48, which indicates a rapid development of object permanence in this species. Results are discussed in relation to object permanence in human babies and in terms of the relevance of object permanence to predatory behavior in the domestic cat. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A survey of epithelial odontogenic tumors and cysts in dogs and cats

A retrospective histologic study of 12 canine and eight feline epithelial odontogenic tumors and cysts was conducted from oral masses (n = 3,917) obtained between 1980 and 1990. No sex or breed predilection was identified. Ameloblastoma was observed in two dogs (case Nos. 1, 2) 6 and 8 months of age. Calcifying epithelial odontogenic tumors were seen in a dog (case No. 3) and in two cats (case Nos. 4, 5) between 8 and 16 years of age. Ameloblastic fibroma (or fibroameloblastoma) was observed in cats (case Nos. 6-10) only. Inductive fibroameloblastoma was observed in four cats (case Nos. 6-9) up to 1 year of age, whereas ameloblastic fibroma was seen in a 14-year-old cat (case No. 10). A single ameloblastic odontoma was identified in a 20-month-old dog (case No. 11). Two complex odontomas occurred in a 6-month-old (case No. 12) and a 4-year-old (case No. 13) dog. Odontogenic cysts were identified in five dogs (case Nos. 14-18) aged 4.5 months to 16 years and in a 1-year-old cat (case No. 19) and have not been previously reported in these species. These cysts were lined by a stratified epithelium reminiscent of the appearance of ameloblastic epithelium. An odontogenic keratocyst with prominent central parakeratotic keratinization was identified in one 9-year-old female dog (case No. 20). Almost all epithelial odontogenic tumors were circumscribed, benign tumors that warranted a good prognosis for survival, although local recurrence may have followed (or may follow) incomplete excision. Calcifying epithelial odontogenic tumors may be locally invasive. Of six odontogenic cysts (case Nos. 14-19), two (case Nos. 15, 18) gave rise to basi-squamous carcinomas. The classification and behavior of epithelial odontogenic tumors and cysts in human beings, dogs, and cats are discussed.     

Restoration of sexual behavior and dopaminergic neurotransmission by long term exogenous testosterone replacement in aged male rats

PURPOSE: We investigated the effects of long-term testosterone replacement on copulatory behavior and dopaminergic neurotransmission in the medial preoptic area of aged male rats. MATERIALS AND METHODS: The rats were divided into 3 groups depending on testosterone replacement. Those in the long-term replacement group were castrated at the age of 12 months and received testosterone replacement thereafter for 12 months. In the short-term replacement group, rats were castrated at the age of 22 months and high or low dose testosterone replacement was done for 2 months. The control group consisted of aged rats 24 months old and young rats 12 weeks old, neither of which had been castrated or received testosterone replacement. We observed sexual behavior in rats of these groups. After a behavioral test, we measured the tissue concentration of dopamine in the MPOA and the change rate of the extracellular dopamine level induced by infusion of N-methyl-D-aspartic acid (NMDA) in the MPOA and compared the long-term replacement and no-replacement groups. RESULTS: The rats in the long-term replacement group showed a mount rate at the same level as that of young rats at 6 weeks after starting replacement and it was maintained to 24 months of age. Their mount rate was significantly higher than that of the rats with the short-term replacement. A significantly higher change rate of dopamine release was recognized in the long-term group; however, no significant difference in the concentration of dopamine was recognized between aged rats with long-term replacement and those without replacement. CONCLUSIONS: Aged rats (24 months old) with long-term testosterone replacement maintained almost the same level of mount behavior as young rats (12 weeks old). The results imply that long-term testosterone replacement may favorably alter the decline in the process of sexual activity with aging. The restoration by testosterone replacement of dopaminergic activity in the MPOA may be involved in the maintenance of sexual function in aged rats.     

Individual differences in contrast sensitivity functions: longitudinal study of 4-, 6- and 8-month-old human infants

Contrast sensitivity functions (CSFs) of 25 infants were measured longitudinally at 4, 6 and 8 months of age using a preferential-looking method and the method of constant stimuli. Sine-wave gratings varied from 0.27 to 4.32 c/deg, contained eight unattenuated cycles (with edges tapered to uniform gray), and rose to the desired contrast in 2 sec. (1) The average CSF was described on log-log coordinates by a band-pass function. With development it increased in overall sensitivity to contrast, shifted its peak toward slightly higher spatial frequencies, and increased its high frequency cutoff. (2) Log sensitivity at the CSF peak was slightly higher for female than male infants at 6 months, consistent with the hypothesis that vernier acuity (which also may differ between the sexes at this age) is partly mediated by analyzers tuned to low frequencies. (3) Within age groups the individual differences were such that log sensitivities for neighboring spatial frequencies generally correlated more highly than distant frequencies. With development the correlations among distant frequencies below 1.0 c/deg increased. Monte Carlo simulations of a model that shifts spatial analyzers to higher frequencies with age reproduced these results but simulations of adultlike, unshifting analyzers did not. (4) Measures taken 2 months apart tended to correlate more highly than those taken 4 months apart, though some individual differences in the CSF peak remained stable over 4 months.     

The development of spatial and temporal contrast sensitivity

This paper reviews work on the development of spatial and temporal contrast sensitivity in human infants. Both electrophysiological and behavioral techniques have been used. Infants' spatial contrast sensitivity functions exhibit a large deficit in spatial resolution and overall contrast sensitivity relative to adult functions. These measurements also reveal continuous development between one and six months of age. Infants' temporal resolution does not exhibit a large deficit relative to adults'. Indeed, critical flicker frequency is essentially adult-like by two months of age. This combination of coarse spatial resolution and fine temporal resolution is analogous to what is observed in the peripheral retina of the adult visual system.