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At least 775 records · Page 43Linked to original sources
PubMed1997

Cognitive neuropsychology and its application to children.

Cognitive neuropsychology has been used successfully in the analysis of adult neuropsychological disorders in both verbal and nonverbal domains. When applied to children, it aims to construct models on the basis of functional lesions manifest within developing systems and provides a theoretical framework within which patterns of intact and deficient skills can be charted over time. These patterns constrain possible underlying models. In highlighting potential individual differences in the acquisition of skills and indicating intact skills within subjects, cognitive neuropsychology may also enable a precise description of the locus of difficulty and potential circumventory routes for remediation around it. The theoretical assumptions of cognitive neuropsychology and issues relevant to its methodology are discussed, including the terminology and principles of modularity, the significance of individual differences and the use of case studies, the dynamics of developing systems, current views on plasticity, and distinctions between developmental and acquired disorders. The application of cognitive neuropsychology to children is discussed in relation to three cognitive areas: face recognition disorders, language disorders and arithmetical disorders. These illustrate the similarities that there are between many developmental cognitive neuropsychological disorders and those seen in adults following brain injury. Models derived from studies of adults are helpful in enabling understanding of both face recognition disorders and arithmetical disorders in childhood. Within language systems, a variety of different types of disorder are evident, which not only relate to receptive and productive difficulties but differentially affect the core components of the language system. All of the disorders discussed illustrate the limitations of functional plasticity in development. In each case, there is not a generalised deficit resulting from degradation of capabilities independent of task requirements. Rather, there are focal and selective disorders which affect subcomponents of cognitive systems. In some cases, genetic factors may constrain compensatory mechanisms.

Adolescent↗
PubMed2003

Assembly dynamics of the bacterial cell division protein FTSZ: poised at the edge of stability.

FtsZ is a prokaryotic tubulin homolog that assembles into a ring at the future site of cell division. The resulting "Z ring" forms the framework for the division apparatus, and its assembly is regulated throughout the bacterial cell cycle. A highly dynamic structure, the Z ring exhibits continual subunit turnover and the ability to rapidly assemble, disassemble, and, under certain circumstances, relocalize. These in vivo properties are ultimately due to FtsZ's capacity for guanosine triphosphate (GTP)-dependent, reversible polymerization. FtsZ polymer stability appears to be fine-tuned such that subtle changes in its assembly kinetics result in large changes in the Z ring structure. Thus, regulatory proteins that modulate FtsZ's assembly dynamics can cause the ring to rapidly remodel in response to developmental and environmental cues.

Bacillus subtilis↗
PubMed2003

Spatial and temporal control of differentiation and cell cycle progression in Caulobacter crescentus.

The dimorphic and intrinsically asymmetric bacterium Caulobacter crescentus has become an important model organism to study the bacterial cell cycle, cell polarity, and polar differentiation. A multifaceted regulatory network orchestrates the precise coordination between the development of polar organelles and the cell cycle. One master response regulator, CtrA, directly controls the initiation of chromosome replication as well as several aspects of polar morphogenesis and cell division. CtrA activity is temporally and spatially regulated by multiple partially redundant control mechanisms, such as transcription, phosphorylation, and targeted proteolysis. A multicomponent signal transduction network upstream CtrA, containing histidine kinases CckA, PleC, DivJ, and DivL and the essential response regulator DivK, contributes to the control of CtrA activity in response to cell cycle and developmental cues. An intriguing feature of this signaling network is the dynamic cell cycle-dependent polar localization of its components, which is believed to have a novel regulatory function.

Bacterial Proteins↗
PubMed2003

Two-year evaluation of telepathology.

We evaluated a dynamic telepathology system in routine use after a two-year developmental phase. In two three-month studies, two years apart, all intraoperative frozen sections were examined by one pathologist via the telepathology system. Laboratory technicians sampled tissues at gross examination and were connected with the pathologist by videoconference. Specimens were immediately reviewed after the telepathology diagnosis by the same diagnostician. In the second study there were 342 cases. The mean time required to diagnose small specimens such as biopsies was 8 min (range 4-14); for specimens with extensive gross examination it was 22 min (range 10-45). The telepathology and traditional frozen-section diagnoses agreed in 99.4% of cases, but telepathology took two to four times longer for gross and histological examinations, and up to 10 times longer for histological examination only. There were five false diagnoses (1.5%), two of which originated from telepathology (0.6%) and were recognized in the subsequent light microscopy review. Telepathology is not a replacement for light microscopy, but should be regarded as a complementary technique.

Diagnostic Errors↗
PubMedDate not supplied

Effect of cold exposure on survival and stress protein expression of Drosophila melanogaster at different development stages.

The effect of cold treatment (0 degrees C) on the survival of different developmental stages of the fruit-fly Drosophila melanogaster, and the dynamics of stress protein synthesis in the salivary gland were investigated. It was shown that low temperature stability of the D. melanogaster depended on both the stage of development and the duration of the low temperature influence. The synthesis of new proteins was determined in the cells of the salivary glands of 5-day old larvae after cold treatment. They were distinguished from the heat shock proteins with the exception of the protein with molecular weight 70 kDa.

Animals↗
PubMed2003

[Forty-six year old baby].

In this paper, an extraordinary mother-son relationship involving 46 year-old, married, male patient with three children is discussed. He had never had any psychiatric complaint until his mother's death. However, he developed severe depressive and somatic symptoms following his 80 year-old mother's death. He showed no significant improvement after previous outpatient treatments and was admitted to the Psychiatric Department of Ege University School of Medicine with complaints of tension, insomnia, fatigue, anhedonia, hopelessness and pain all over his body. It was discovered that this man, who was loved and respected by both his family and his peers, used to suck his mother's breast twice daily. This act was no secret and was not considered a reason for seeking psychiatric help, a symptom of a disorder, or a source of distress for the son, mother, or any other family member. A phenomenon like this has never been reported in the literature before. We discuss this phenomenon through the dynamic formulation of the case using data from his psychiatric and developmental history as well as direct observation and psychological tests.

Aged↗
PubMedDate not supplied

Prestructural determinants in a case of phobia.

Questions of genesis, dynamics, and treatment techniques, in what is hypothesized as the first developmental layer of agoraphobic or pan-anxious symptoms, are considered. In the patient described it was concluded that this layer of anxiety came from many inadequate ego functions brought about by a mother who could not (for reasons speculated about in her history) tolerate autonomous functioning in this child. This mother-child reality shaped the course of the patient's first four years of therapy. During this period of treatment there was more material that lent itself to reconstruction of her real world as perceived by the developing ego, while there was a paucity of fantasy material available. It is suggested that the symptom state called agoraphobia resulted from continuous stimulation since infancy from a mother making dyadic functioning appear imperative for the patient's emotional equilibrium. In similar cases, the initial phase of therapy should focus on reconstructions and clarifications of past and present dyadic relationships. This, as well as other technical interventions to aid development of attenuated ego functions, appears to be necessary as the initial and crucial aspect of therapy.

Adult↗
PubMed1996

Trajectories of poverty and children's mental health.

Using data from three waves of the Children of the National Longitudinal Surveys of Youth data set (1986, 1988, 1990), we examine the dynamic relationship between children's family histories of poverty and their developmental trajectories of mental health. Children who were poor in 1986 or who had prior histories of poverty had higher levels of depression and antisocial behavior in that year. Furthermore, subsequent poverty histories were also related to children's mental health trajectories. The number of years that children were poor between 1986 and 1990 correlates significantly with changes in children's antisocial behavior during those years. Finally, rates of increase in antisocial behavior were substantially higher for children with histories of persistent poverty during those years than for transiently poor or nonpoor children. These results demonstrate the accelerating behavioral disadvantages faced by persistently poor children.

Adolescent↗
PubMedDate not supplied

[The Landau-Kleffner syndrome. SPECT and EEG investigations].

Four children (three boys and one girl) with acquired epileptic aphasia (the Landau-Kleffner syndrome) have been observed in the Department of Developmental Neurology University of Medical Sciences in Poznań. We present the dynamic of clinical symptoms and fluctuations in EEG studies. The changes in the brain in single photon emission computed tomography (SPECT) during remission of clinical symptoms are discussed.

Brain↗
PubMed1988

Analysis of the developmental stages of Pneumocystis carinii, in vitro.

Rat derived Pneumocystis carinii cultured in vitro was analyzed by a variety of light microscopic and staining techniques for identification of developmental stages and changes in these populations over time in culture. Evaluation of culture dynamics based on a limited number of life cycle stages indicated that trophic replication contributed significantly to the observed growth in vitro. Identification of additional life cycle stages, particularly early cyst forms, suggested that the process of maturation from early precyst to mature cyst may also contribute to the net growth. All developmental stages identified from culture were verified by their presence in stained impression smears of infected rat lung. Based on these data, a tentative life cycle for P. carinii in vitro has been proposed.

Animals↗
PubMed1998

The impact of host developmental status on baculovirus replication

The yield of progeny occlusion bodies from a baculovirus infection is a critical parameter governing viral population dynamics in the field. Previous evidence has suggested that the ability of the virus to block host development may be an important factor in determining yield of progeny virus. Here, we explore the relationship between yield, dose, and host developmental status at the time of infection during Autographa californica nucleopolyhedrovirus infection of final instar Heliothis virescens. The data indicate that occlusion body yield is strongly inversely dependent on the time elapsed after ecdysis before the insect is infected. The later in the instar the infective dose is received, the lower the efficiency with which the virus can block host development. The occlusion body yield from insects whose development is completely arrested is more than fourfold greater than the yield from insects that have initiated prepupal development. Dose is also an important factor, with high-dose infections more likely to lead to developmental arrest. Thus, the infection parameters that give rise to optimal progeny virus yield are infection at high dose early in the instar. Analysis of ecdysteroid titers demonstrated that only low levels of ecdysteroids are detectable in insects whose development is completely arrested. In contrast, in insects whose development was only partially arrested, extremely high ecdysteroid titers were frequently observed. These data support the hypothesis that the function of the baculovirus ecdysteroid UDP-glucosyltransferase gene is to delay or block host development, with the benefit of increasing the yield of progeny virus. Copyright 1998 Academic Press.

Journal Article↗
PubMed2003

Growth and sexual dimorphism in orangutan crania: a three-dimensional approach.

New insights may be gleaned by taking an ontogenetic approach to investigations of adult dimorphism. Previous work in this area relied on traditional, caliper-based, morphometric methods, and produced conflicting results. This study uses a three-dimensional (3-D) approach for both local and global form comparisons of sex-specific growth and growth patterns. 3-D coordinate data were collected for 20 landmarks on 94 orangutan crania divided into five developmental stages. Data were analyzed using Euclidean distance matrix analysis (EDMA). Results indicate that differences in growth patterns between male and female orangutans exist in the youngest age intervals. Dimorphic patterns are strongest in the face and basicranium at the youngest age intervals, and in the face and neurocranium during adult stages. Females grow substantially more in the cranial base and face during the youngest age groups, while males grow more than females in all anatomical regions later in development. Growth in the palate was similar between sexes. Sexual dimorphism may be produced through the continued growth of one sex relative to the other, representing differences in timing, or growth duration. Dimophism may also result from different growth rates between sexes, where one sex develops faster than the other sex in the same time interval. Orangutan males and females differ in both the rate and duration of their craniofacial development. The data analysis technique used here, EDMA, was integral in identifying dynamic growth processes rather than just the static end results of each developmental stage.

Animals↗
PubMed2003

Movement systems as dynamical systems: the functional role of variability and its implications for sports medicine.

In recent years, concepts and tools from dynamical systems theory have been successfully applied to the study of movement systems, contradicting traditional views of variability as noise or error. From this perspective, it is apparent that variability in movement systems is omnipresent and unavoidable due to the distinct constraints that shape each individual's behaviour. In this position paper, it is argued that trial-to-trial movement variations within individuals and performance differences observed between individuals may be best interpreted as attempts to exploit the variability that is inherent within and between biological systems. That is, variability in movement systems helps individuals adapt to the unique constraints (personal, task and environmental) impinging on them across different timescales. We examine the implications of these ideas for sports medicine, by: (i) focusing on intra-individual variability in postural control to exemplify within-individual real-time adaptations to changing informational constraints in the performance environment; and (ii) interpreting recent evidence on the role of the angiotensin-converting enzyme gene as a genetic (developmental) constraint on individual differences in physical performance. The implementation of a dynamical systems theoretical interpretation of variability in movement systems signals a need to re-evaluate the ubiquitous influence of the traditional 'medical model' in interpreting motor behaviour and performance constrained by disease or injury to the movement system. Accordingly, there is a need to develop new tools for providing individualised plots of motor behaviour and performance as a function of key constraints. Coordination profiling is proposed as one such alternative approach for interpreting the variability and stability demonstrated by individuals as they attempt to construct functional, goal-directed patterns of motor behaviour during each unique performance. Finally, the relative contribution of genes and training to between-individual performance variation is highlighted, with the conclusion that dynamical systems theory provides an appropriate multidisciplinary theoretical framework to explain their interaction in supporting physical performance.

Adaptation, Physiological↗
PubMed2005

Neuronal cell death and population dynamics in the developing rat geniculate ganglion.

In contrast to many neuronal systems, the pattern of developmental neuronal degeneration in the rat geniculate ganglion has remained undefined. To address this issue sectioned geniculate ganglia from embryonic day 13 to postnatal day 3 have been examined using standard histological techniques, TdT-mediated dUTP-digoxigenin nick end labeling to verify apoptotic activity, bromo-deoxyuridine incorporation to monitor neuronal precursor proliferation, and anti-beta-neurotubulin III to verify the neuronal identity of pycnotic cells. Results summed from alternate (embryonic day 13) or every third (embryonic day 14-postnatal day 3) section show that neuronal degeneration occurs as early as embryonic day 13 (6.8% of neurons counted), well before geniculate innervation of lingual taste buds at embryonic day 16. A degenerative peak occurs at embryonic day 17 (9.5%) followed by a decline (1.7% at embryonic day 18) and leveling off (0.1%-0.2% at embryonic day 22-postnatal day 3). Thus, geniculate neuronal degenerative pattern includes both innervation-associated histogenetic and morphogenetic cell death. Corresponding counts of mean neuronal numbers in the sections showed a continual rise from embryonic day 13 through embryonic day 18 (approx. 330-760) followed by a slight decline at embryonic day 19 (to approx. 630) and then a final leveling off at 800-825 by embryonic day 20. This pattern differs from many other developing neural systems which show a major population crash during initial target contact. It likely reflects different but slightly overlapping neuronal precursor proliferation and degeneration patterns in multiple geniculate neuronal subpopulations.

Animals↗
PubMed2001

Dynamic temporal and spatial regulation of the cdk inhibitor p57(kip2) during embryo morphogenesis.

The complete developmental expression pattern of the cyclin dependent kinase inhibitor (CDKI) p57(kip2) has not been reported, here we report a detailed study of the localization of p57(kip2) protein during mouse organogenesis. We show that p57(kip2) is coincident with key stages of differentiation of several organs, some but not all of which are affected in Beckwith-Weidermann syndrome, a human congenital syndrome characterized by foetal overgrowth and childhood tumours.

Animals↗
PubMed1989

In utero exposure of mice to diethylstilbestrol alters neonatal ovarian follicle growth and development.

The prenatal exposure of mice to diethylstilbestrol (DES, 10 micrograms/kg on day 15 of gestation) caused both quantitative and structural alterations in ovarian follicles within the neonatal ovary. At birth, control ovaries consisted of small type 1 and 2 ovarian follicles located in the ovarian cortex. By postnatal day 7, ovarian follicle development had advanced to the type 4 stage with larger follicles located within the ovarian medulla. In DES-exposed animals, ovarian follicle maturation was advanced with type 3b and 4 follicles appearing 24 h prior to their appearance in control animals. Also, type 5 ovarian follicles were present on postnatal day 6 in experimental animals but were never seen in control animals. In addition to an alteration in ovarian follicle dynamics, the diameter of individual ovarian follicles was transit time between the various stages of follicular development which results in a greater number of developmentally advanced ovarian follicles being present during neonatal ovarian development. The mechanism by which prenatal exposure to DES alters ovarian follicle dynamics during neonatal development is not known.

Animals↗
PubMed2000

Mental retardation and developmental disabilities influenced by environmental neurotoxic insults.

This paper sets a framework for the discussion of neurotoxicity as a potentially major contributor to the etiology of many types of mental retardation and developmental disabilities. In the past the literatures on developmental neurotoxicology and on mental retardation have evolved independently, yet we know that the developing brain is a target for neurotoxicity in the developing central nervous system through many stages of pregnancy as well as during infancy and early childhood. Our definitions and theories of mental retardation and developmental disabilities affect the models of neurotoxicity we espouse. For instance, models of developmental risk in neurotoxicology have guided environmental regulation to reduce the likelihood of neurotoxic effects. On the other hand, models of developmental risk for mental retardation aim not only at primary prevention,but also at secondary and tertiary prevention through early intervention. In the future, dynamic models of neuroplasticity based on the study of gene-brain-behavior relationships are likely to guide our views of developmental neurotoxicology and prevention of mental retardation and other disabilities.

Developmental Disabilities↗
PubMed2002

Low birth weight, social factors, and developmental outcomes among children in the United States.

We used six waves of the National Longitudinal Survey of Youth-Child Data (1986-1996) to assess the relative impact of adverse birth outcomes vis-à-vis social risk factors on children's developmental outcomes. Using the Peabody Individual Achievement Tests of Mathematics and Reading Recognition as our outcome variables, we also evaluated the dynamic nature of biological and social risk factors from ages 6 to 14. We found the following: (1) birth weight is significantly related to developmental outcomes, net of important social and economic controls; (2) the effect associated with adverse birth outcomes is significantly more pronounced at very low birth weights (< 1,500 grams) than at moderately low birth weights (1,500-2,499 grams); (3) whereas the relative effect of very low-birth-weight status is large, the effect of moderately low weight status, when compared with race/ethnicity and mother's education, is small; and (4) the observed differentials between moderately low-birth-weight and normal-birth-weight children are substantially smaller among older children in comparison with younger children.

Adolescent↗