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PubMedDate not supplied

Analyzing evolutionary patterns in amniote embryonic development.

Heterochrony (differences in developmental timing between species) is a major mechanism of evolutionary change. However, the dynamic nature of development and the lack of a universal time frame makes heterochrony difficult to analyze. This has important repercussions in any developmental study that compares patterns of morphogenesis and gene expression across species. We describe a method that makes it possible to quantify timing shifts in embryonic development and to map their evolutionary history. By removing a direct dependence on traditional staging series, through the use of a relative time frame, it allows the analysis of developmental sequences across species boundaries. Applying our method to published data on vertebrate development, we identified clear patterns of heterochrony. For example, an early onset of various heart characters occurs throughout amniote evolution. This suggests that advanced (precocious) heart development arose in evolutionary history before endothermy. Our approach can be adapted to analyze other forms of comparative dynamic data, including patterns of developmental gene expression.

Age Factors↗
PubMed1994

Temperament and the development of personality.

We present a psychobiological approach to personality development, incorporating developmental principles outlined by R. B. Cairns (1979). We review individual differences in temperament and ask how a temperamental approach to personality might be congruent with these complex and flexible principles. We then illustrate the nature of temperamental processes by considering several developmental topics. We first consider the interaction of infant distress-proneness and maternal behavior in the development of attachment. We then describe the development of self-regulatory mechanisms, emphasizing development of conscience, aggression, and mastery motivation. Finally, we briefly review mechanisms of temperament and environment interaction, illustrating these processes through variable developmental pathways for risk of adolescent and adult psychopathology. Throughout, we stress the idea that temperamental models of personality development are dynamic, interactive, and fit well with Cairns's developmental principles.

Adolescent↗
PubMed1996

A developmental and component analysis of active sleep.

A wide variety of hypotheses have been put forth that address the functional significance of active sleep. Despite the well-accepted fact that active sleep expresses itself predominantly in the perinatal period, the vast majority of these functional hypotheses are applicable largely, if not exclusively, to the adult. We build on the developmental approaches of previous researchers and propose that the individual components of active sleep (e.g., myoclonic twitches, rapid eye movements) exhibit unique developmental and phylogenetic histories and may serve independent functions in the developing organism. This dynamic perspective leads to specific experimental approaches aimed at the developmental roles of these components in the neonate, their maintenance roles in the adult, and the means by which these various components coalesce temporally in what is commonly referred to as a behavioral state.

Adolescent↗
PubMed1999

Adolescents and popular culture. A psychodynamic overview.

Adolescents occupy a difficult and seemingly elusive developmental space, which makes them enigmas to most adults, including psychotherapists. Building upon dynamic theory such as that formulated by Winnicott or Erikson, this paper explores the relationship between adolescents and material elements of popular culture within a psychodynamic and developmental framework. Theoretical perspectives are integrated with case material to illustrate some of the roles of popular music and fashion in the lives of teenagers as a means of expression and in potential therapeutic alliance formation, dynamic understanding and working through developmental conflicts in displacement.

Adolescent↗
PubMed2005

Remodeling dendrites during insect metamorphosis.

The genesis of dendritic shape during development sets in place key characteristics of a neuron's physiology and connectivity. During this construction, a cell interprets intrinsic cell-specific developmental programs and cues from the environment to generate its final phenotype. In insects that undergo complete metamorphosis certain neurons function in the larval nervous system and then remodel to generate an adult-specific arbor. By studying the dendrites of neurons that undergo such a cellular metamorphosis, one can explore the mechanisms that underlie both stereotyped pruning and local remodeling. Live imaging techniques in intact Drosophila have been especially useful in examining the outgrowth of the adult-specific dendritic arbors in remodeling dendritic arborizing (da) sensory neurons. These neurons show an initial scaffold-building phase during which the cell establishes the overall shape of the arbor and then switch to an elaboration phase where the arbor is filled out with higher order branches. The cellular machinery employed during these two phases is different, with branch retraction being a prominent feature of the scaffold building phase but absent from the elaboration phase. The transition between these two modes does not appear to be "hard-wired" but is plastic and under the extrinsic control of developmental hormones. This transition in branch dynamics may also involve changes in calcium signaling in the growing arbor. The potential relationship between hormone-induced transcriptional change and the calcium dynamics in dendritic morphogenesis is discussed.

Animals↗
PubMed1999

Cdc42, Rac1, and their effector IQGAP1 as molecular switches for cadherin-mediated cell-cell adhesion.

Cell-cell adhesion is a dynamic process in various cellular and developmental situations. Cadherins, well-known Ca(2+)-dependent adhesion molecules, are thought to play a major role in the regulation of cell-cell adhesion. However, the molecular mechanism underlying the rearrangement of cadherin-mediated cell-cell adhesion is largely unknown. Cdc42 and Rac1, belonging to the Rho small GTPase family, have recently been shown to be involved in the regulation of cell-cell adhesion. In addition, IQGAP1, an effector for Cdc42 and Rac1, has been shown to regulate the cadherin function through interaction with beta-catenin, a molecule associated with cadherin. In this review, we will summarize the mode of action of Cdc42 and Rac1 as well as IQGAP1 as molecular switches for the cadherin function, and then discuss physiological processes in which the Cdc42/Rac1/IQGAP1 system may be involved.

Animals↗
PubMed2002

Lysophospholipids and their G protein-coupled receptors in inflammation and immunity.

Among the family of lipid-derived mediators, the group of lysophospholipids including lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) have growth-related and -unrelated effects on diverse cell types including lymphocytes, macrophages, smooth muscle cells, endothelial cells, and neuronal cells. This review summarizes the known effects of lysophospholipids and their G protein-coupled receptors (GPCRs) in inflammation and immunity. Lysophospholipids have the capacity to evoke and modulate immune responses by attracting and activating T-cells, B-cells and macrophages directly and influencing their interactions with other cell types. Immune cells express multiple subsets of lysophospholipid receptors, which are critical for specific cellular responses such as proliferation and migration that are fundamental to immunity. Investigation of the expression pattern of EDG-receptors on human T-cells revealed a dynamic transcriptional regulation influenced by both developmental stages and activation states. Other lipid mediators like psychosine and other GPCRs for lipid mediators like G2A also may be involved in the development of normal immune and inflammatory reactions and diseases. These observations suggest that agonists and antagonists for lysophospholipid receptors may influence immune responses.

Animals↗
PubMed2000

Developmental changes in pharmacokinetics and pharmacodynamics of warfarin enantiomers in Japanese children.

OBJECTIVE: To clarify developmental changes in the pharmacokinetics and dynamics of warfarin enantiomers to establish rational pediatric dosage. METHODS: Plasma concentrations of unbound warfarin enantiomers, vitamin K1 and vitamin K-dependent proteins (that is, prothrombin fragments 1+2, protein C, and the protein-induced by vitamin K absence) and international normalized ratio were measured in 38 prepubertal (1 to 11 years), 15 pubertal (12 to 18 years), and 81 adult (37 to 76 years) patients given long-term warfarin therapy. Unbound oral clearance values for warfarin enantiomers and its body weight-, body surface area-, and liver weight-normalized values, as well as the pharmacodynamic parameters, were compared among the groups. RESULTS: The prepubertal, pubertal, and adult patients exhibited comparable mean plasma concentrations of unbound warfarin enantiomers for pharmacologically more active (S)-warfarin. Although the unbound oral clearance of (S)-warfarin for the prepubertal patients was significantly (P < .01) less than that for the adult group (346 versus 637 mL/min), the body weight-normalized unbound oral clearance for the prepubertal patients was significantly (P < .01) greater than that for the adults and showed a negative correlation (P < .05) with age. In contrast, no differences were observed in the liver weight-normalized unbound oral clearance for (S)-warfarin between the prepubertal and adult groups. The prepubertal patients showed significantly (P < .01 or .05) lower plasma concentrations of protein C and prothrombin fragments 1+2 and greater international normalized ratio and international normalized ratio/dose than the adults. In contrast, the pubertal patients showed largely similar pharmacokinetic and pharmacodynamic properties to adults. CONCLUSION: Liver weight may be a better parameter than body weight for estimating the warfarin doses for prepubertal patients on the basis of the corresponding adult values. Augmented responses to warfarin in children should also be taken into account for estimating warfarin doses for children.

Adolescent↗
PubMed1968

Changes in cell wall polysaccharides associated with growth.

Changes in the polysaccharide composition of Phaseolus vulgaris, P. aureus, and Zea mays cell walls were studied during the first 28 days of seedling development using a gas chromatographic method for the analysis of neutral sugars. Acid hydrolysis of cell wall material from young tissues liberates rhamnose, fucose, arabinose, xylose, mannose, galactose, and glucose which collectively can account for as much as 70% of the dry weight of the wall. Mature walls in fully expanded tissues of these same plants contain less of these constituents (10%-20% of dry wt). Gross differences are observed between developmental patterns of the cell wall in the various parts of a seedling, such as root, stem, and leaf. The general patterns of wall polysaccharide composition change, however, are similar for analogous organs among the varieties of a species. Small but significant differences in the rates of change in sugar composition were detected between varieties of the same species which exhibited different growth patterns. The cell walls of species which are further removed phylogenetically exhibit even more dissimilar developmental patterns. The results demonstrate the dynamic nature of the cell wall during growth as well as the quantitative and qualitative exactness with which the biosynthesis of plant cell walls is regulated.

Journal Article↗
PubMed1993

Differences between human sperm and somatic cell DNA in CpG methylation within the HLA class I chromosomal region.

PROBLEM: We investigated the possible negative regulatory mechanisms that repress classical human leukocyte antigen (HLA) class I gene expression in human spermatozoa and searched for novel testis-specific coding sequences that might be present in MHC class I chromosomal region. METHOD: We performed a comparative DNA methylation analysis of this genomic region in both purified human spermatozoa and mononuclear blood cells from the same donors, using methylation-sensitive restriction enzymes followed by classical or pulsed field gel electrophoresis and hybridization with HLA class I locus-specific probes. RESULTS: Unmethylated CpG sites were detected in the 3' part of HpaII tiny fragments of the HLA-F and HLA-G genes in spermatozoal DNA. In contrast, no difference was observed in the methylation status of the HLA-B, HLA-C, and HLA-E genes between germ and somatic cells. CpG unmethylation events were also detected in several parts of this chromosomal region (outside the known loci) in spermatozoal DNA. CONCLUSIONS: These results suggest that this genomic region undergoes changes in its DNA methylation pattern during the developmental process. We hypothesize that these dynamic changes have functional importance, including a possible transcriptional activity of nonclassical class I genes and/or as yet undescribed testis-specific coding sequences.

Base Sequence↗
PubMed2007

Nerve ring of the hypostome in hydra: is it an origin of the central nervous system of bilaterian animals?

A hypothesis, 'the nerve ring in hydra shares a common origin with the central nervous system in bilaterian animals', is discussed in this review. The nerve ring of hydra is a ring of neurons whose neurites make a bundle running circumferentially around the hypostome just above the tentacle zone. This nervous structure has unique features in the hydra nervous system. It shows a tight association of neurons in contrast to the diffuse nerve net seen in other regions. It shows static developmental characters in contrast to the dynamic features of hydra nerve net present in other regions. Moreover, its structure and location are similar to the central nervous system (CNS) of other animals without a complex CNS such as nematodes and starfishes. Functions of the hydra nerve ring are also studied to test the hypothesis. The identified function is a crumpling of the tentacles, corresponding to the function of the inner nerve ring of hydrozoan jellyfish. The jellyfish nerve ring is considered to be a primitive central nervous system of radiates. Considering all the information available, the hypothesis is highly possible.

Animals↗
PubMed1984

Paraphilias: phenomenology and classification.

DSM-III incorrectly designates the majority of paraphilias as atypical. Only eight are named, and those because of their forensic history, rather than their pathology and therapeutic need. In this paper, thirty-odd paraphilias are subdivided into six categories on the basis of their phenomenological dynamics. The new concept of the developmental lovemap is introduced for the first time. A new treatment originated by the author in 1966 combines an androgen agonist with counseling therapy.

Combined Modality Therapy↗
PubMed1989

[Moral development in children].

In child psychiatry the developmental aspect is emphasized. Recognition of normal sequence of development in so-called "normal children" makes it possible to reveal pathological conditions (either retardation or acceleration of development, distortion or atypical development). Change-motion-development are philosophical categories considered a manifestation or life--of psychobiological maturation and growth. When investigating the moral development three theories were applied: the developmental theory (Piaget)--learning (Kohlberg), the dynamic theory (Sandler). Among factors which influence in a certain way the moral behaviour the following were selected: age, sex, temperament, family environment. The author describes three stages of moral development in children: preventional stage (moral heteronomy) up to the age of 8 years, conventional and pst conventional (moral autonomy) in adolescence.

Child↗
PubMed1978

[The formation of tooth germs in teratomas].

The teeth buds which are observed in some teratomas ought to provide a useful system for the study of the development of organ structures in these tumours. They exhibit well defined characteristics in space and time. In contrast with normal development tooth bud formation in teratomas display malformations and other observable characteristics which are primarily the consequence of defects in coordination of activities among cells. Cyto-differentiation appears to be normal and the defective organogenesis must represent a breakdown of the principles which underlie the organization of structures. The possible role of the environment in organizing structure is discussed. Teratomas are unique biological systems which display in a dynamic way a panoply of teratological developmental processes of which teeth buds represent a fragmentary, repetitive and conspicuous expression.

Cell Differentiation↗
PubMed1989

A developmental perspective on psychotherapy and psychoanalysis.

Some of the most important issues in dynamic psychiatry involve the mechanisms of action of and the distinctions between psychotherapy and psychoanalysis. Recent advances in developmental psychology and in clinical practice and theory provide new insights into these long-standing controversies.

Humans↗
PubMed2002

Mechanisms regulating lineage diversity during mammalian cerebral cortical neurogenesis and gliogenesis.

During mammalian cerebral cortical development, neural stem cells (NSCs) present within periventricular generative zones give rise to successive waves of neurons and radial glia, followed by oligodendrocytes and astrocytes. The molecular and cellular mechanisms that orchestrate these precisely timed and progressive maturational events are still largely undefined. These developmental processes are likely to involve the dynamic interplay of environmental signals, cell-cell interactions and transcriptional regulatory events. The bone morphogenetic proteins (BMPs), an expanding subclass of the transforming growth factor beta cytokine superfamily, may represent an important set of environmental cues for these progressive maturational events because of the broad profiles of developmental expression of the requisite BMP ligands, receptor subunits and intracellular transduction elements, and because of their versatile roles in promoting a spectrum of cellular processes intimately involved in progressive neural fate decisions. The BMPs also interact with complementary regional environmental signals such as the basic fibroblast growth factor (bFGF) and sonic hedgehog (Shh) that promote earlier stages of NSC expansion, self-renewal, lineage restriction and incipient lineage commitment. The ability of these cytokines and trophic signals to act within specific neurodevelopmental contexts may, in turn, depend on the composite actions of cell-cell contact-associated signals, such as Notch-Hes-mediated lateral inhibitory pathways, and additional transcriptional modulatory events, such as those mediated by members of the inhibitor of differentiation (ID) gene family that encode a novel set of negative basic helix-loop-helix (bHLH) transcription factors. In this chapter, we will examine the distinct roles of these different classes of developmental cues in defining the biological properties of an integrated cerebral cortical developmental signaling network. Ongoing studies in this exciting area of mammalian central nervous system (CNS) development will help to identify important molecular and cellular targets for evolving pharmacological, gene and stem cell therapeutic interventions to combat the pathological sequelae of a spectrum of acquired and genetic disorders of the central nervous system.

Animals↗
PubMed1993

Sonographic diagnosis of developmental dysplasia of the hip: importance of increased thickness of acetabular cartilage.

OBJECTIVE: Dynamic and static sonography has become the imaging technique of choice in the diagnosis and follow-up of developmental dysplasia of the hip. The purpose of this study was to determine the value of using the thickness of acetabular cartilage as measured on sonograms as a discriminating factor in the diagnosis of developmental dysplasia. SUBJECTS AND METHODS: We evaluated 220 consecutive hips in 110 infants referred for sonography because of possible developmental dysplasia (referred group). We also evaluated 66 hips in 33 infants who had normal findings on physical examination and no clinical or sonographic evidence of the abnormality (control group). The thickness of the acetabular cartilage, the alpha angle, and the presence of subluxation or dislocation on sonograms were recorded. Follow-up clinical and sonographic examinations were performed between 6 weeks and 6 months after the initial examinations in 19 patients in whom the thickness of the acetabular cartilage was increased (> 3.5 mm) and in 20 patients in whom the thickness was in the normal range (< 3.5 mm). All 39 patients who had follow-up examinations were from the referred group, and all these hips were normal according to conventional sonographic criteria on the initial examination. RESULTS: Of the 220 hips in the referred group, 170 were initially classified as normal according to traditional sonographic standards, and 50 were classified as dysplastic (alpha angle < 55 degrees with or without subluxation or dislocation). The mean thickness of the acetabular cartilage in the control group was 2.6 mm (1 SD = 0.37) as compared with 4.6 mm (1 SD = 0.71) for the dysplastic hips in the referred group. The mean thickness in the hips classified as normal in the referred group was 3.0 mm. Nineteen hips in the referred group in which the thickness of the acetabular cartilage was greater than in the control group (i.e., > 3.4 mm) were imaged again during follow-up examinations. Sixteen of these 19 hips had become clinically unstable or dysplastic according to conventional sonographic criteria. CONCLUSION: The results suggest that sonographic evidence of increased thickness of the acetabular cartilage is an early sign of developmental dysplasia of the hip and that close follow-up of infants with this abnormality is indicated.

Acetabulum↗