Organic osmolytes increase expression of specific tight junction proteins in skin and alter barrier function in keratinocytes.

BACKGROUND: The epidermal barrier is important for water conservation, failure of which is evident in dry-skin conditions. Barrier function is fulfilled by the stratum corneum, tight junctions (TJs, which control extracellular water) and keratinocyte mechanisms, such as organic osmolyte transport, which regulate intracellular water homeostasis. Organic osmolyte transport by keratinocytes is largely unexplored and nothing is known regarding how cellular and extracellular mechanisms of water conservation may interact. OBJECTIVES: We aimed to characterize osmolyte transporters in skin and keratinocytes, and, using transporter inhibitors, to investigate whether osmolytes can modify TJs. Such modification would suggest a possible link between intracellular and extracellular mechanisms of water regulation in skin. METHODS: Immunostaining and quantitative polymerase chain reaction of organic osmolyte-treated organ-cultured skin were used to identify changes to organic osmolyte transporters, and TJ protein and gene expression. TJ functional assays were performed on organic osmolyte-treated primary human keratinocytes in culture. RESULTS: Immunostaining demonstrated the expression of transporters for betaine, taurine and myo-inositol in transporter-specific patterns. Treatment of human skin with either betaine or taurine increased the expression of claudin-1, claudin-4 and occludin. Osmolyte transporter inhibition abolished this response. Betaine and taurine increased TJ function in primary human keratinocytes in vitro. CONCLUSIONS: Treatment of skin with organic osmolytes modulates TJ structure and function, which could contribute to the epidermal barrier. This emphasizes a role for organic osmolytes beyond the maintenance of intracellular osmolarity. This could be harnessed to enhance topical therapies for diseases characterized by skin barrier dysfunction.

Penetration of different molecular weight hydrolysed keratins into hair fibres and their effects on the physical properties of textured hair.

OBJECTIVE: To investigate the effects of different molecular weight (MW), wool derived hydrolysed keratins (i.e. peptides) on the physical properties of relaxed textured hair. METHODS: Very curly hair of African origin was relaxed using sodium hydroxide-based treatment. Relaxed hair was treated with different MW peptides derived from keratin protein and an amino acid, L-Leucine. The low-MW keratin peptides were 221 Da, the mid-MW keratin peptides were approximately 2577 Da, and the high-MW keratin peptides were approximately 75 440 Da. The penetration of these different peptides into relaxed hair was evaluated using a laser scanning micrometre and by fluorescence microscopy. The effect of these compounds on single-fibre mechanical properties and thermal properties was evaluated using tensile and DSC testing, respectively. RESULTS: Low- and mid-MW compounds were able to penetrate deep into the hair cortex. High-MW peptide adsorbed onto the hair surface and possibly slightly penetrated into the outer layers of the fibre surface. Both mid- and high-MW keratin peptides, increased Young's modulus and reduced hair breakage at 20% and 80% relative humidity. With the exception of mid-MW peptide, other peptides and amino acid were not able to modify thermal properties of relaxed textured hair. CONCLUSIONS: Our data suggest that low-MW compounds may increase hair volume, and high-MW peptides may repair damage on freshly relaxed textured hair.

OBJECTIF: Etudier les effets des kératines hydrolysées, issues de la laine, de différents poids moléculaires (PM) (par ex : peptides) sur les propriétés physiques des cheveux texturés défrisés. MÉTHODES: Les cheveux très bouclés d'origine africaine ont été défrisés à l'aide d'un traitement à base d'hydroxyde de sodium. Les cheveux défrisés ont été traités avec des peptides de différents PM dérivés de la protéine de kératine et un acide aminé, la L-leucine. Les peptides de kératine de PM faible étaient de 221 Da, les peptides de kératine de PM moyen étaient d'environ 2 577 Da et les peptides de kératine de PM élevé étaient d'environ 75 440 Da. La pénétration de ces différents peptides dans les cheveux défrisés a été évaluée à l'aide d'un micromètre à balayage laser et par microscopie à fluorescence. L'effet de ces composés sur les propriétés mécaniques à fibre unique et les propriétés thermiques a été évalué à l'aide de tests de traction et de l'analyse calorimétrique différentielle (ACD), respectivement. RÉSULTATS: Les composés de PM faible et moyen ont pu pénétrer en profondeur dans le cortex des cheveux. Les peptides de PM élevé ont été adsorbés sur la surface des cheveux et ont éventuellement pénétré, légèrement, dans les couches externes de la surface des fibres. Les peptides de kératine de PM moyen et élevé ont augmenté le module de Young et réduit la casse des cheveux à 20 % et 80 % d'humidité relative. À l'exception des peptides de PM moyen, d'autres peptides et acides aminés n'ont pas pu modifier les propriétés thermiques des cheveux texturés défrisés. CONCLUSIONS: Nos données suggèrent que les composés de PM faible peuvent augmenter le volume des cheveux et que les peptides de PM élevé peuvent réparer les dommages sur les cheveux texturés fraîchement défrisés.

A review of shampoo surfactant technology: consumer benefits, raw materials and recent developments.

Surfactants form the core of all shampoo formulations, and contribute to a wide range of different benefits, including cleansing, foaming, rheology control, skin mildness and the deposition of benefit agents to the hair and scalp. The purpose of this review was to assist the design of effective, modern, shampoo surfactant technologies. The mechanisms through which surfactants help deliver their effects are presented, along with the appraisal techniques through which surfactant options can be tested and screened for product development. The steps that should be taken to select the most appropriate blend of surfactants are described, and useful information on the most widely used surfactants is provided. The review concludes with an examination of recent developments in 'greener' surfactants, 'sulphate-free' technologies and structured liquid phases for novel sensory properties and for suspending benefit agents.

The high intensity diffractometer for residual stress analysis (HIDRA), a third generation residual stress mapping neutron diffractometer at the high flux isotope reactor.

This paper describes the hardware and software upgrades, operation, and performance of the high intensity diffractometer for residual stress analysis (HIDRA) instrument, a residual stress mapping neutron diffractometer located at the High Flux Isotope Reactor at Oak Ridge National Laboratory in Oak Ridge Tennessee, USA. Following a major upgrade in 2018, the new instrument has a single 3He multiwire 2D 30 × 30 cm2 position sensitive detector, yielding a field of view of 17° 2θ. The increase in the field of view (from 4° 2θ) from the previous model instrument has contributed to the tremendous improvement in the out of plane solid angle such that the 3D count rate could be obtained easily. Accordingly, the hardware, software, Data Acquisition System (DAS), and so on have also been updated. Finally, all these enhanced features of HIDRA have been ably demonstrated by conducting multi directional diffraction measurements in the quenched 750-T74 aluminum, and the evolved and improved strain/stress mappings are presented.

Current capabilities of the residual stress diffractometer at the high flux isotope reactor.

The engineering diffractometer 2nd Generation Neutron Residual Stress Facility (NRSF2) at the Oak Ridge National Laboratory's High Flux Isotope Reactor was built specifically for the mapping of residual strains. NRSF2 is optimized to investigate a wide range of engineering materials by providing the user a selection of monochromatic neutron wavelengths to maintain the selected Bragg reflection near 2θ = 90°, which is the optimal scattering geometry for strain mapping. Details of the instrument configuration and operation are presented, and considerations for experimental planning are also discussed. Selected examples of recent residual stress work completed with NRSF2 are presented to highlight capabilities.

System-wide repercussions of damage to the immature visual cortex.

Damage of the primary visual cortex in mammals, including humans, severely disrupts vision by disconnecting much of the cognitive-processing machinery of extrastriate cortex from its source of visual signals in the retina. Studies of the anatomical consequences of damage to the immature primary visual cortex in cats reveal system-wide repercussions on neural circuitry that includes the retina, thalamus, midbrain and extrastriate cortex. The repercussions modify circuits that support relatively normal signal processing and the sparing of certain visually guided behaviors such as aspects of complex-pattern recognition and orienting to novel stimuli introduced into the visual field. These studies have implications for understanding the consequences of damage to the visual cortex in infant monkeys and humans, and for devising therapeutic strategies to attenuate defects in vision induced by cortical lesions.

Changes in the kinetic parameters of hepatic gamma-glutamyltransferase from streptozotocin-induced diabetic rats.

Previous research has shown that the enzymatic activity of hepatic gamma-glutamyltransferase was increased in streptozotocin-induced diabetic rats with no increase in the expression of the protein. The current work has characterized the differences in the kinetic properties of hepatic gamma-glutamyltransferase from diabetic versus control rats. Hepatic gamma-glutamyltransferase was purified from control male and female rats and from rats made diabetic 30 days previously with streptozotocin. The maximal velocity and the Michaelis constant were determined for the purified enzyme with two separate donors (L-gamma-glutamyl-p-nitroanilide or L-gamma-glutamyl-(7-amido-4-methylcoumarin)) in the presence of one of eight acceptors (L-alanine-glycine, L-glycine-glycine, L-methionine, L-glutamate, L-alanine, L-glutamine, L-phenylalanine or L-aspartate). With both donors, hepatic gamma-glutamyltransferase from diabetic rats had a consistently higher kinetic efficiency than gamma-glutamyltransferase from controls. The kinetic efficiency percent increase of diabetic over control gamma-glutamyltransferase when averaged across all acceptors was higher in males than in females. With L-gamma-glutamyl-p-nitroanilide, the kinetic efficiency increase of diabetic over control gamma-glutamyltransferase was higher with poor acceptors than with highly efficient acceptors. These data indicate that there are differences in the physical properties of hepatic gamma-glutamyltransferase from diabetic versus control rats and from female versus male rats.

Specific nutrient abnormalities in asymptomatic HIV-1 infection.

OBJECTIVE: To determine whether specific nutrient abnormalities occur in earlier stages of HIV-1 infection, thereby preceding the marked wasting and malnutrition that accompany later stages of the infection. DESIGN: A longitudinal investigation to determine biological, psychological and social factors thought to influence the progression and outcome of HIV-1 infection. Nutritional status was assessed using biochemical measurement of nutrient levels, dietary history, anthropometry and clinical examination for the signs and symptoms of nutritional deficiency or excess. SETTING: The study was performed on an outpatient basis at the University of Miami School of Medicine. PARTICIPANTS: One hundred homosexual men, aged between 20 and 55 years, who were asymptomatic other than persistent generalized lymphadenopathy (Centers for Disease Control stage III) and 42 age-matched homosexual men demonstrated to be free of HIV-1 infection at two 6-month intervals. MAIN OUTCOME MEASURES: Biochemical measurement of nutrient status, dietary history, anthropometry, clinical signs or symptoms of nutritional excess or deficiency were obtained for all participants. RESULTS: Despite few differences in mean blood levels of specific nutrients, prevalence of specific nutrient abnormalities was widespread among HIV-1-infected subjects, compared with non-infected male homosexual controls. Overtly and marginally low blood levels of vitamins A (18%), E (27%), riboflavin (26%), B6 (53%), and B12 (23%), together with copper (74%) and zinc (50%) were documented in HIV-1-seropositive subjects. With the exception of riboflavin, zinc, and copper, a similar prevalence of abnormalities among HIV-1-seronegative controls was not observed. CONCLUSION: Specific nutrient abnormalities occur with relative frequency in asymptomatic HIV-1 infection and may contribute to the rate and form of HIV-1 disease progression.

Extrinsic visual and auditory cortical connections in the 4-day-old kitten.

The major extrinsic projections to and from the visual and auditory cortical areas were examined in 4-day-old kittens using axonal transport of horseradish peroxidase (HRP) and/or tritiated proline. Six different afferent and seven different efferent systems were studied; all 13 were present by postnatal day 4 as revealed by either HRP, or autoradiography alone, or these two techniques combined. Topographical projections were found for the corticopetal pathways from the thalamus and claustrum and for the corticofugal pathways to the thalamus, claustrum, striatum, and tectum, as well as for the inter- and intrahemispheric pathways. No topographical relations were seen in projections to the cortex from the basal ganglia or the lower brainstem. The results of the present study indicate that most or all of the major extrinsic connections of the kitten's visual and auditory cortical areas are present neonatally, and that both the cells of origin and the axonal targets are arranged topographically much like those of adult cats. However, the origins of callosal projections from visual cortex are more widespread in newborn kittens than in adult cats. In addition, the laminar arrangements of the kitten's corticocortical connections differ from those of adult cats in a number of details. The results suggest that the sparing of some visual and auditory functions after neonatal lesions occurs despite the fact that the cortical areas removed have formed extrinsic connections.

Role of the superior colliculus in analyses of space: superficial and intermediate layer contributions to visual orienting, auditory orienting, and visuospatial discriminations during unilateral and bilateral deactivations.

The superior colliculus (SC) has been implicated in spatial analyses of the environment, although few behavioral studies have explicitly tested this role. To test its imputed role in spatial analyses, we used a battery of four spatial tasks combined with unilateral and bilateral cooling deactivation of the upper and intermediate layers of the superior colliculus. We tested the abilities of cats to orient to three different stimuli: (1) moving visual, (2) stationary visual, (3) stationary white-noise aural. Furthermore, we tested the ability of the cats to discriminate the relative spatial position of a landmark. Unilateral cooling deactivation of the superficial layers of the SC induced a profound neglect of both moving and stationary visual stimuli presented in, and landmark objects located within, the contralateral hemifield. However, responses to auditory stimuli were unimpaired. Unilateral cooling deactivation of both the superficial and intermediate layers induced a profound contralateral neglect of the auditory stimulus. Additional and equivalent deactivation of the opposite SC largely restored orienting to either moving visual or auditory stimuli, and restored landmark position reporting to normal levels. However, during bilateral SC deactivation, orienting to the static visual stimulus was abolished throughout the entire visual field. Overall, unilateral SC deactivation results show that the upper and intermediate layers of the SC contribute in different ways to guiding behavioral responses to visual and auditory stimuli cues. Finally, bilateral superior colliculus deactivations reveal that other structures are sufficient to support spatial analyses and guide visual behaviors in the absence of neural operations in the superior colliculus, but only under certain circumstances.

Capacity of the retinogeniculate pathway to reorganize following ablation of visual cortical areas in developing and mature cats.

The purpose of the present study was to determine the pattern and density of retinal projections to the dorsal lateral geniculate nucleus (dLGN) following ablation of visual cortical areas in developing cats of different postnatal ages and in mature cats. The terminations of retinal projections to the dLGN were evaluated following the injection of tritiated amino acids into one eye. Regardless of age, a visual cortical ablation of areas 17 and 18 induces massive death of neurons within the regions of the dLGN that are linked topographically to the cortical areas removed. However, the pattern of retinal projections to these degenerated regions of the dLGN differs depending upon whether the cortical lesion is incurred early in postnatal life or in adulthood. Following ablation on the day of birth (P1), virtually all surviving cells were found in the C-complex of dLGN with only a token number in the A-laminae. Correspondingly, retinal projections were maintained to the C-complex of the nucleus and were barely detectable in the degenerated A-laminae. However, in cats in which areas 17 and 18 had been removed in adulthood (> or = 6 months of age) retinal projections were maintained to the A-laminae even though nearly all neurons in those laminae had degenerated. Moreover, a subgroup of animals that incurred area 17 and 18 ablations at P1 showed that the modification of retinal projections to the A-laminae occurs within the first postnatal month, and an additional subgroup showed that retinal projections become increasingly resistant to the degenerative events in the dLGN that follow ablation of areas 17 and 18 at progressively older ages during the first postnatal month. Furthermore, retinal inputs also respond, in an age-dependent way, to degeneration of neurons in the C-complex induced by extension of the cortical ablation to include extrastriate visual areas.

Effect of ethynodiol diacetate and mestranol on serum folic acid and vitamin B12 levels and on tryptophan metabolism in baboons.

The effect of an oral contraceptive agent on serum folate and vitamin B12 levels and on some aspects of tryptophan metabolism in the baboon has been investigated. Folate levels were not affected by this treatment. Vitamin B12 levels were lowered during oral contraceptive treatment (P smaller than 0.1) and increased during a 30-day period of pyridoxine supplementation (P smaller than 0.01). Trends indicating deterioration of glucose tolerance and abnormal tryptophan metabolism were also observed. Definite conclusions concerning the effect of oral contraceptive agents on nutritive parameters could not be made. This is in keeping with the vast volume of literature published on the effects of oral contraceptive agents in humans and other species. It is concluded that perhaps, due to the biologically variable responses to oral contraceptive agents by individuals of any species, studies of serum levels of vitamins and other superficial biochemical parameters. Further, we conclude that the baboon could be a useful model for the study of endocrine influences on nutritive parameters, first because endocrine parameters resemble those of humans and second, because experimental protocols can be rigidly adhered to.

Vitamin fluctuations in the blood of female baboons in relation to normal menstrual cycles, treatments with Lo-Ovral or Depo-Provera and a selected vitamin supplement.

Both endogenous and exogenous sex steriods may induce changes in plasma vitamin levels by altering availability, transport, binding, or use of vitamins. This study investigated some of those mechanisms by observing in a primate model (baboon), the blood levels of carotene, folate, vitamins A, B12, and C, and the status of vitamin B6, riboflavin, and thiamin. The latter three vitamins were studied by determining their relationship to asparate aminotransferase, glutathione reductase, and thiamin transketolase, respectively. The vitamin screen was obtained throughout normal menstrual cycles in 10 baboons and weekly for 55 wk in five baboons receiving Lo-Ovral and in four baboons receiving Provera. During the last 16 wk of hormonal treatment, all baboons received a vitamin supplement containing pyridoxine, riboflavin, and thiamin. Only carotene (p less than 0.0001), vitamin A (p less than 0.05), glutathione reductase (p less than 0.05), and thiamin transketolase (p less than 0.05) levels fluctuated significantly during normal menstrual cycles. Long-term treatment with Lo-Ovral and Provera resulted in numerous changes but there were very few differences between the two hormone treatments. Compared to control levels, vitamin C was elevated during treatment while all three enzyme activities were lowered. Vitamin supplementation raised asparate aminotransferase and glutathione reductase activity and the levels of folic acid, vitamin A, and carotene. This study demonstrates that interactions between hormones and vitamins and among vitamins themselves, are complex but it is likely that the treatments used here caused no physiologically significant vitamin alterations.

Estrogen stimulation of conjugase activity in the uterus of ovariectomized rats.

Recent observations have indicated that uterine folic acid conjugase (pterolypolyglutamyl hydrolase) undergoes rhythmic variation during the reproductive cycle of the rat. In the present study conjugase activity and ratios of "total" folate to "free" folate were determined in uterine homogenates of ovariectomized rats, with ane without estrogen stimulation. An increase in conjugase levels and a relative increase in the "free" folate component occurred in castrated animals 12 to 18 hours following injection of 10 mug of estradiol-17beta.

PIP: Estrogen stimulation of conjugase activity in the uterus was studied in ovariectomized rats. The rats were sacrificed either without estrogen replacement or at varying time intervals after the sc administration of 10 mcg of estradiol 17-beta. The uterine horns were processed for folate determinations or for conjugase assay. A significant increase (p less than .001) of conjugase activity was seen in the animals sacrifieced 20 hours after administration of the hormone. The ratio of total-to-free folate was significantly lower (p less than .001) than the control 20 hours after injection of the hormone. The drop in both free and total folates could not be explained.

Cyclic variations in folate composition and pteroylpolyglutamyl hydrolase (conjugase) activity of the rat uterus.

The "free" and "total" folate content and the activity of conjugase (pteroylpolyglutamyl hydrolase) were determined in homogenates of rat uteruses from animals sacrificed at specific stages of the reproductive cycle. Among 47 animals, conjugase activity was approximately twice as great during proestrus as in any other stage (P less than 0.001). A significant increase in total folate content (P less than 0.01) was observed in these animals, associated with a relatively greater increase in the free component than in the polyglutamyl component during proestrus. A similar decline in the ratio of total to free folate was observed (P less than 0.02) in a second group of 43 animals in which conjugase was inactivated even more rapidly than in the first group. Vascular engorgement was excluded as an explanation for the changes observed in proestrus. Since certain polyglutamyl derivatives of folate are potent inhibitors of thymidylate synthetase, the observed shift in ratio between total and free folates could be conducive to enhanced activity of this rate-limiting reaction of cellular proliferation. The data suggest that cycles of uterine cell growth and involution may be mediated through hormonally induced changes in enzymes governing the length of gamma-glutamyl folate chains. It is postulated that the mechanism involves the conversion of metabolic inhibitors into active coenzymes for one-carbon transfer reactions, and vice versa.

Quantitation of xanthurenic acid in rabbit serum using high performance liquid chromatography.

Xanthurenic acid (XA) has been quantified in the serum of normal and vitamin B6-deficient rabbits using high performance liquid chromatography. The concentration of XA in the serum of normal and B6-deficient rabbits was 141 and 2275 ng/ml, respectively. The coefficient of variation for a series of dilutions of standard XA (3.9 to 1000 ng) ranged from 45.5% at the lower limit of the curve to 10.9% at the higher range of the curve. The minimum detectable level was 3.9 ng/ml. Serum samples spiked with reference XA exhibited a parallel dose response. The percentage recovery of XA from serum samples was 80.8%. The procedure, which requires 1 to 2 ml of serum, is sensitive and may be a useful tool for assessing B6 nutritional parameters as well as the physiological role of XA. It offers advantages over urinary procedures because it is more sensitive, more specific, and allows the study of blood levels of XA.

Zinc concentration in plasma and erythrocytes of subjects receiving folic acid supplementation.

It has been suggested that oral supplements of folic acid interfere with the intestinal absorption of zinc and may have toxic side effects. The concentrations of Zn and folate in blood were monitored in a group of women with cervical dysplasia randomly assigned to receive 10 mg/d of either folic acid (pteroylglutamic acid) or ascorbate. Fifty subjects were evaluated after 2 mo; 21 of the same subjects were evaluated again after 4 mo. No untoward clinical effects were observed. Significant elevation of erythrocyte folate above the baseline value was observed in the supplemented group but not in the placebo group (p less than 0.001). The concentration of Zn in plasma and erythrocytes did not change significantly in either the folate-treated or placebo groups after 2 and 4 mo. It is concluded that carefully controlled clinical intervention trials of this type do not impose a risk of depleting the concentration of Zn in erythrocytes and plasma.

Association of vitamin B6 status with parameters of immune function in early HIV-1 infection.

Nutritional deficiencies have been documented to affect immune function. The present study indicates that vitamin B6 deficiency is prevalent in CDC stage III HIV-1-infected subjects, despite adequate dietary vitamin B6 intake. As vitamin B6 deficiency has been previously shown to affect immune function, these relatively asymptomatic HIV-1-infected patients were examined for evidence of a relationship between vitamin B6 deficiency and immune dysregulation. Vitamin B6 status in HIV-1-infected subjects was significantly associated with functional parameters of immunity [multivariate F(3,36) = 3.70, p less than or equal to 0.02]. Additional analyses indicated that overtly deficient participants exhibited significantly decreased lymphocyte responsiveness to the mitogens phytohemagglutinin and pokeweed, and reduced natural killer cell cytotoxicity, compared to subjects with clearly adequate vitamin B6 status (chi 2 = 8.78, df = 3, p less than 0.04). Vitamin B6 status was not related to immune cell subpopulations, e.g., CD4, CD8 cell number, or level of serum immunoglobulins. The results of this study indicate that while vitamin B6 status is not a primary etiological factor in HIV-1-related immunological dysregulation, it appears to be an important cofactor of immune function.

Evidence for greater sight in blindsight following damage of primary visual cortex early in life.

This review compares the behavioral, physiological and anatomical repercussions of lesions of primary visual cortex incurred by developing and mature humans, monkey and cats. Comparison of the data on the repercussions following lesions incurred earlier or later in life suggests that earlier, but not later, damage unmasks a latent flexibility of the brain to compensate partially for functions normally attributed to the damaged cortex. The compensations are best documented in the cat and they can be linked to system-wide repercussions that include selected pathway expansions and neuron degenerations, and functional adjustments in neuronal activity. Even though evidence from humans and monkeys is extremely limited, it is argued on the basis of known repercussions and similarity of visual system organization and developmental sequence, that broadly equivalent repercussions most likely occur in humans and monkeys following early lesions of primary visual cortex. The extant data suggest potentially useful directions for future investigations on functional anatomical aspects of visual capacities spared in human patients and monkeys following early damage of primary visual cortex. Such research is likely to have a substantial impact on increasing our understanding of the repercussions that result from damage elsewhere in the developing cerebral cortex and it is likely to contribute to our understanding of the remarkable ability of the human brain to adapt to insults.

Visual discrimination by cats given lesions of visual cortex in one or two stages in infancy or in one stage in adulthood.

Sparing of visual function was studied in cats with bilateral cortical damage to Areas 17 and 18 and most of Area 19. Cats with lesions made in 2 stages, on Postnatal (P) Days 3 and 6, in 1 stage on P6, or in 1 stage in adulthood were compared with sham-operated controls on 10 visual discrimination tasks. On some tasks, both groups of cats that underwent surgery as infants showed considerable sparing of function compared with cats that had surgery as adults; the latter group showed a marked impairment. However, on several of the discriminations, 2-stage lesions permitted almost total sparing of pattern vision, whereas 1-stage lesions made neonatally were almost as debilitating as those incurred in adulthood. The findings suggest that differential behavioral consequences can follow physiological or anatomical changes, or both, that occur within a 4-day neonatal interoperative period.