Developmental changes in concept utilization among normal and retarded children.

Examined the concepts employed by 100 normal children in kindergarten-Grade 4 (Study 1), and by 48 retarded vs 48 normal children matched for mental ages ranging from 5 to 11 yrs (Study 2). Ss were required to select pairs of pictures from a large array of pictures depicting common objects and to explain the basis for their pairing responses. Factor analysis of the conceptual responses of normal Ss revealed factors for abstraction (nominal and functional concepts as opposed to perceptible concepts) and complimentarity ("go together" responses as opposed to similarity responses). Retarded Ss differed from normals primarily in their use of more complimentary and fewer similarity concepts. The developmental course of concept utilization for normals was characterized as a change from perceptible to nominal and functional concepts, while that for retarded Ss was characterized as a change from complimentary to similarity concepts. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes of antioxidant enzymes in kidney and liver from rats

The five principal antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase in the kidney and liver, and the total hepatic glutathione were determined in rats of different ages (1, 2, 3, 6, and 12 months). Variance analysis proved the effect of age on the measured enzymes in the respective organ with the exception of glutathione S-transferase. The behavior of the enzymes was not uniform, and there were both increased and decreased changes in the two organs. A clear correlation between cellular antioxidative capacity and the age-specific processes of growing or aging could not be seen. A far more complicated network of interactions has to be assumed.     

Developmental changes in synaptic formation in the hypothalamic arcuate nucleus of female rats

The hypothalamic arcuate nucleus (ARCN) of female rats at 5, 20, 45 and 90 days of age was examined ultrastructurally. Axodendritic and axosomatic synapses were counted in 18,000 mum2 area of the ARCN in each brain. Axodendritic and axosomatic synapses in the ARCN of day 5 rats were very small in number. Axon terminals contained small spherical vesicles (SSVs, 40-60 nm in diameter). Occasionally large granular vesicles (LGVs, 75-130 nm in diameter) were found to coexist with SSVs in the endings. Pre- and postsynaptic membranes were thin. The ARCN at this age exhibited a large extracellular space which decreased with advancing age. In day 20 rats, axodendritic and axosomatic synapses increased in number up to about one-half of those of day 45 or day 90 animals. Synaptic vesicles increased in number and mitochondria were frequently encountered in the axon terminals. Pre- and postsynaptic membranes became thicker than those of day 5 rats. Further increase in the number of axodendritic and axosomatic synapses in the ARCN of day 45 rats was observed, and there were no significant difference in the morphology and incidence of synapses between day 45 and day 90 rats. Synaptic vesicles were numerous and pre- and postsynaptic membranes were thick. In tissue incubated with 5-hydroxydopamine (5-OH-DA) before fixation, small granular vesicles (SGVs, about 50 nm in diameter) which were labeled with 5-OH-DA were detected in a certain number of endings in all material taken from each age group, but the incidence of synapses containing SGVs was usually low. From these results, it can be proposed that an increase in the number of synapses in the ARCN is correlated wihh functional maturation of the ARC neurons.     

Developmental changes in tritium autoabsorption

Developmental changes in autoabsorption of tritium emissions were examined in 30 brain regions in the rat at Postnatal Days 0, 4, 7, 10, 14, 21, and 28 and adulthood. Rats received tritiated 2-deoxyglucose in vivo. Alternate brain sections were extracted in chloroform, and autoradiographs were developed from extracted and nonextracted sections. The ratio of optical density values in extracted vs nonextracted sections was used to determine autoabsorption for each structure. Three principal temporal patterns in the development of adult levels of autoabsorption, determined by the optical density ratios, were identified: (1) a minimal increase pattern in which autoabsorption rose only slightly between birth and adulthood; (2) a plateau pattern in which a rapid early increase was followed by stable values; and (3) a late increase pattern in which autoabsorption remained relatively constant until Postnatal Day 28, with a large increase between Day 28 and adulthood. In addition, optical density ratios fluctuated during the second postnatal week in close to one-third of the structures. The data suggest that developmental events affecting the ratio of gray to white matter produce substantial local variations in the development of adult levels of autoabsorption that are distinct for each structure. To correct for autoabsorption effects in ontogenetic studies using tritium autoradiography, it is necessary to determine directly the degree of autoabsorption at a particular time point for the structure of interest. Our results indicate that the technique of in vivo administration of tritiated 2-deoxyglucose followed by chloroform extraction appears to be a sensitive and reproducible method for assessing autoabsorption at all ages.     

Developmental changes in word recognition strategies

Attempted to determine when children develop adultlike strategies in word recognition and use the entire configuration as a basis for a response rather than individual letters. A total of 144 kindergartners, 1st-6th graders, and undergraduates were asked to choose an alternative which most resembled a stimulus trigram, quadrigram, or quingram. Ss could respond on the basis of individual letter position and overall word shape. There was a clear developmental trend such that, with increasing age, Ss were more likely to choose alternatives with the same shape as the stimulus. There was also a tendency to choose response alternatives with the same 1st letter as the stimulus through 4th grade, followed by a decreasing tendency to rely on the 1st letter starting with the 5th grade. Results are considered supportive of E. J. Gibson's (see record 1972-22179-001) hypothesis of a developmental change with increasing age and schooling in feature analysis and extraction. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanical and morphometrical changes in progressive bilateral pneumothorax and pleural effusion in normal rats

A variety of neurotransmitter receptor changes occur after a course of electroconvulsive seizures (ECS) in rats, including an increased density of adenosine A1 sites. Adenosine antagonism has been related to the proconvulsant action of methylxanthines such as caffeine. We determined tonic-clonic seizure duration in rats given ECS with caffeine (0-175 mg/kg, IP) after a course of one or six daily ECS. A single day of ECS did not affect the dose-dependent proconvulsant action of caffeine. After six daily ECS, the proconvulsant action of caffeine was reduced. After nine daily ECS, an A1 antagonist (8-cyclopentyl-1,3-dipropylxanthine) and an A2A antagonist (1-allyl-3,7-dimethyl-8-p-sulfophenylxanthine) showed reduced proconvulsant activity. The results suggest that the reduced proconvulsant action of caffeine after chronic ECS depends on adenosine antagonism.     

Developmental changes in the attribution of blame.

A story completion test was constructed to measure developmental changes in the methods used by children to assign blame in situations where the cause of unpleasant events was left ambiguous. Ss were 115 elementary school children between the ages of 5 and 12 years. The tendency to blame others decreased with age whereas responses involving sharing of blame or recognition of impersonal and accidental causes increased with age. The story completion method provides a simple way of measuring behavior in this important area of personality development. The findings suggest that a valuable tool for personality assessment of children could be constructed from the stories used in the present study together with story completion items designed to tap mechanisms for coping with other critical stress situations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recruitment of lymphoblasts derived from peripheral and intestinal lymph to synovium and other tissues in normal rats and rats with adjuvant arthritis

Recruitment of [125I]iododeoxyuridine-labeled syngeneic lymphoblasts from thoracic duct (TD) lymph into periarticular tissues has been examined after intravenous administration to normal rats and to rats with adjuvant-induced arthritis. Uptake of label was observed in the inflamed paws of arthritic rats and cells were located in synovium and periarticular bone marrow by autoradiography. Uptake was greater with lymphoblasts from donors in the late prodromal phase of adjuvant-induced arthritis (arthritic donors) than from normal donors. With arthritic donors, recruitment of lymphoblasts from TD lymph was greater than from mesenteric duct lymph, suggesting that most of the joint-seeking lymphoblasts in arthritic rats arose in peripheral lymphoid tissues. Lymphoblasts from arthritic donors were also detected in the synovium of paws from normal rats. Recovery of lymphoblasts was monitored in other tissues; this revealed, in arthritic recipients, competition among extra-articular sites of inflammation (adjuvant injection site, draining lymph nodes, and lymph nodes draining affected joints), the lungs, and the inflamed synovium for recruitment of lymphoblasts from arthritic donors. In contrast, while some lymphoblasts from normal donors were recruited to inflamed joints, the small intestine was the main site of recruitment. The results reflect the known propensity of T lymphoblasts generated in peripheral lymphoid tissues to enter inflamed tissues. However, some mesenteric duct lymphoblasts also entered inflamed synovium. The observed pattern of recruitment of lymphoblasts to synovium is pertinent to the pathogenesis of arthritis, the potential roles of arthritogenic and bystander lymphocytes and the known links between the joints and inflammation in the intestine.     

Developmental changes in perception of nonnative vowel contrasts.

Discrimination of 2 German vowel contrasts was examined in English-learning infants of 6–8 and 10–12 mo of age using a head turn procedure. The younger infants were better able than the older infants to discriminate the nonnative contrasts, but performance at 6–8 mo was below levels that have been reported for nonnative consonant contrasts. A 2nd experiment using a habituation looking procedure showed that 4-mo-old infants discriminated both German vowel contrasts, but the 6-mo-olds could not. The findings are consistent with previous consonant work, revealing a shift from a language-general toward a language-specific pattern during the 1st yr of life. However, that shift begins earlier in development for vowels than for consonants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in the voltage-dependence of neocortical NMDA responses

A change in the response of neocortical neurons to N-methyl-D-aspartate (NMDA) was observed during the first 2 weeks of postnatal development. When NMDA was bath applied, the membrane current-voltage relationship recorded in neurons from postnatal day (PN) 3-5 rats displayed a region of decreased inward current at hyperpolarized membrane potentials. By PN 9-14, the net inward current at hyperpolarized potentials was significantly less than that recorded in PN 3-5 neurons. These results indicate that a developmental increase in the voltage-dependence of NMDA responses exists, which may be due to changes in magnesium sensitivity of the NMDA receptor.     

Developmental changes in the organization of prereaching movements.

Examined how the kind and amount of prereaching activity change with age during the period preceding successful grasping of objects. 23 infants were tested at 3-wk intervals from the 1st week of life to 16 wks of age. 12 Ss were also seen at 19 wks of age. At each session, the S was presented with an object moving slowly in different ways in front of him or her. In the middle of each session there was also a 1-min period with no object present. Results show that the amount of prereaching declined at 7 wks and that this decrease was contingent on the presence of the object. Ss did not seem to lose interest in the object at this age, but attending to the object inhibited prereaching activity in some way. The form of prereaching also changed at 7 wks, with the fist clenched during the forward extension of the arm. After this age, the amount of prereaching activity again increased and the hand opened during the forward extension, but only when the S looked at the object. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes of tetrahydrobiopterin in rat and human erythrocytes

In the present study, we investigated the developmental changes of (1) plasma and erythrocyte tetrahydrobiopterin (BH4); (2) erythrocyte GTP cyclohydrolase (the rate-limiting enzyme of BH4 biosynthesis); (3) the permeability of erythrocyte membrane to BH4; and (4) plasma phenylalanine, both in healthy human subjects and Wistar rats. In vitro experiments demonstrated passive transport of BH4 into erythrocytes. In humans, BH4 levels as well as the other parameters were fairly consistent across all age groups. In contrast, Wistar rats showed significant developmental changes in erythrocyte BH4, which were not simply correlated to either GTP cyclohydrolase, permeability to BH4 or plasma phenylalanine levels. This may suggest the existence of other factors regulating the homeostasis of BH4, such as BH4-binding capacity in plasma and/or erythrocytes. These species/age differences in erythrocyte characteristics may influence the pharmacological behavior and clinical efficacy of BH4 in humans and experimental animals.     

Developmental and endocrine aspects of normal ovarian aging

The fluorescence plus Giemsa (FPG) and fluorescence in situ hybridization (FISH) techniques have been used to determine, respectively, the frequencies of sister chromatid exchanges (SCEs) and stable chromosome aberrations (translocations) induced by different concentrations of BrdU in the Chinese hamster ovary cell mutant EM9 and its parental line AA8. The results indicate that BrdU induced a high frequency of SCEs and translocations in EM9 as compared with AA8, and that the translocation/dicentric ratio was also higher in the mutant cell line than in the parental cell line in both untreated and BrdU-treated cultures. These observations may indicate a possible relationship between the molecular mechanisms involved in the formation of SCEs and translocations.     

Developmental changes in semantic interpretation of ambiguous words.

Administered homograph measures of vocabulary and semantic interpretation to 81 7th grade and 85 12th grade children to test for patterns of developmental change in language. Developmental progressions were found for enlargement of abstract vocabulary and reduction of biases toward primary (common) and concrete errors of interpretation in sentence contexts. Another experiment using the same measures found a loss of abstract vocabulary in aphasics and a trend toward excessive primary bias in schizophrenics. However, on all other measures of vocabulary and semantic interpretation the mental patients did not perform like the younger Ss in this experiment. Results do not support conceptions of linguistic regression in psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in the infants attention to pattern detail

To assess developmental changes in the importance of stimulus intensity and pattern detail for infants' visual attention, infants of 10, 17, and 25 wk. of age were shown pairs of stimuli equated for stimulus intensity but different in pattern detail (angles or straight lines). The youngest infants gave equivalent amounts of attention to the stimuli of each pair while the two older groups showed a significant preference for the angular stimuli. The results are interpreted as showing the increased attention to elements with development, and a possible explanation of the preference for the angle stimuli is discussed.     

Developmental changes in conformity to peers and parents.

Investigated developmental changes in conformity to parents and peers and relations between parent and peer conformity. In Study 1, 251 children in the 3rd, 6th, 9th, 11th, or 12th grade responded to hypothetical situations in which peers urged the child to perform either antisocial, prosocial, or neutral behaviors. For all types of behavior, the age trends for conformity were curvilinear, and peer conformity peaked in the 6th or 9th grade. In Study 2, 273 children in the 3rd, 6th, 9th, 11th, or 12th grades responded to situations testing conformity to peers on antisocial and prosocial behavior and conformity to parents on prosocial and neutral behavior. For antisocial behavior, a peak in peer conformity was found at the 9th grade. Significant age changes were not found for prosocial behavior. Conformity to parents on both types of behavior decreased steadily with age. With some but not all measures, conformity to parents and conformity to peers were negatively correlated. In addition, the relations between parents and peer conformity changed with age. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in knowledge about different retrieval problems.

Conducted 2 experiments to examine developmental changes from middle childhood to adolescence in metaretrieval plans offered to solve different retrieval problems. In each experiment, 80 children in Grades 3, 5, 7, and 9 made judgments about 2 problems that were more or less external or internal . The spontaneous responses from Exp I revealed an age increase in the number of different ideas generated for the internal problem and an age increase in the number of children who recommended the highly general strategy of retracing one's steps for retrieval. The forced-choice judgments in Exp II revealed the perception that the internal problem is more difficult than the external one and some discrepancy between the "best" strategy most often chosen for each retrieval problem (Exp II) and the strategy most frequently mentioned (Exp I). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in the time-dependent nature of memory retrieval.

Six-month-old infants trained in an operant conditioning procedure were allowed to forget the contingency and were presented with a reminder in a memory-reactivation paradigm. The time course of memory retrieval after the reminder, the relation between the forgetting functions of the newly acquired and the reactivated memory, and the potential contribution of the context to retention after long delays were investigated. Memory retrieval was found to be a time-locked process at 6 months, as at 3 months. Although retrieval was more rapid at the older age, the reactivated memory was more transient than the newly acquired memory at 6 months and remained accessible for a briefer period than at 3 months. A distinctive context was requisite for memory reactivation at 6 months but did not insure it. These studies reveal that the temporal parameters of memory processing change with age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in intracellular pH buffering power in smooth muscle

Hematological toxicity of tacrolimus has been rarely reported. We report two pediatric recipients of liver transplantation with anemia. They were treated with tacrolimus for 8 and 47 months, respectively, before developing pure red cell aplasia (PRCA) confirmed by bone marrow biopsy. The children recovered quickly on withdrawal of tacrolimus. The clinical profile of these children is compared with the only other patient reported in the literature with PRCA due to tacrolimus. All three patients had similar hematological findings. However, the mechanism of the tacrolimus-induced PRCA in these children appears to be different from that reported in the adult patient.     

Developmental changes in speed of information processing in young children.

This study investigated developmental increases in processing speed in young children, relative to adults, with only nonverbal stimuli. R. Kail's (1991) model of the rate of change in processing speed from childhood to adulthood was evaluated. Processing speed was measured in 34 children at 4 years, 37 at 5 years, and 38 at 6 years and in 43 adults, with a battery of 8 computer-administered tests. Results showed clear age-related increases in processing speed that cannot be attributed to increased accuracy and error rate monitoring. Kail's model adequately accounted for the observed rate of developmental change in processing speed; however, the parameter estimates of R. Kail and Y. Park (1992) provided more accurate predictions than did the meta-analytically derived estimates of Kail (1991). Findings support the global developmental trend hypothesis and suggest that this trend extends beyond the range of verbal skills evaluated in previous research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)