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Developmental Dynamics : An Official... Jul 1995We describe a series of stages for development of the embryo of the zebrafish, Danio (Brachydanio) rerio. We define seven broad periods of embryogenesis--the zygote,...
We describe a series of stages for development of the embryo of the zebrafish, Danio (Brachydanio) rerio. We define seven broad periods of embryogenesis--the zygote, cleavage, blastula, gastrula, segmentation, pharyngula, and hatching periods. These divisions highlight the changing spectrum of major developmental processes that occur during the first 3 days after fertilization, and we review some of what is known about morphogenesis and other significant events that occur during each of the periods. Stages subdivide the periods. Stages are named, not numbered as in most other series, providing for flexibility and continued evolution of the staging series as we learn more about development in this species. The stages, and their names, are based on morphological features, generally readily identified by examination of the live embryo with the dissecting stereomicroscope. The descriptions also fully utilize the optical transparancy of the live embryo, which provides for visibility of even very deep structures when the embryo is examined with the compound microscope and Nomarski interference contrast illumination. Photomicrographs and composite camera lucida line drawings characterize the stages pictorially. Other figures chart the development of distinctive characters used as staging aid signposts.
Topics: Animals; Blastocyst; Cleavage Stage, Ovum; Embryo, Nonmammalian; Gastrula; Morphogenesis; Temperature; Time Factors; Zebrafish; Zygote
PubMed: 8589427
DOI: 10.1002/aja.1002030302 -
Cells, Tissues, Organs 2010The staging of human embryos, as distinct from seriation, depends on a morphological scheme devised by Streeter and completed by O'Rahilly, who proposed the term...
The staging of human embryos, as distinct from seriation, depends on a morphological scheme devised by Streeter and completed by O'Rahilly, who proposed the term Carnegie stages. To avoid misconceptions and errors, and to place new findings in perspective, it is necessary to summarize the essentials of the Carnegie system: (1) Twenty-three stages cover the embryonic period, i. e. the first 8 postfertilizational weeks of development. (2) The system is based on internal as well as external features, and the use of only external criteria is subject to serious limitations. For example, precise delineation of stages 19-23 and of the embryonic-fetal transition depends on histological examination. (3) Prenatal measurements are not an integral component of the staging system, and hence a stage should never be assigned merely on the basis of embryonic length. A 20-mm embryo, for example, could belong to any of three stages. Measurements, however, are important for the assessment of age, and very few measurements are available for staged embryos. Presented here and based on accurate staging are the maximum diameter of the chorionic sac, the crown-heel length, the greatest length exclusive of the lower limbs, the biparietal diameter, the head circumference, the length of the hindbrain, the total length of the brain, and the lengths of the limbs as well as of their segments, including the foot length. (4) Prenatal ages are also not an integral part of the staging system and hence a stage should never be assigned merely on the basis of prenatal age. Ages, however, are of clinical importance and their estimate has been rendered more precise by accurate timing of fertilization followed by ultrasonography. Prenatal age is postfertilizational and hence some 2 weeks less than the postmenstrual interval. The term gestational age is ambiguous and should be discarded. Presented here is a new graph showing proposed estimates of age in relation to stages and based on current information.
Topics: Crown-Rump Length; Embryo, Mammalian; Embryonic Development; Female; Humans; Pregnancy; Ultrasonography, Prenatal
PubMed: 20185898
DOI: 10.1159/000289817 -
Journal of Speech, Language, and... Aug 2019Purpose Current approaches to speech production aim to explain adult behavior and so make assumptions that, when taken to their logical conclusion, fail to adequately... (Review)
Review
Purpose Current approaches to speech production aim to explain adult behavior and so make assumptions that, when taken to their logical conclusion, fail to adequately account for development. This failure is problematic if adult behavior can be understood to emerge from the developmental process. This problem motivates the proposal of a developmentally sensitive theory of speech production. The working hypothesis, which structures the theory, is that feedforward representations and processes mature earlier than central feedback control processes in speech production. Method Theoretical assumptions that underpin the 2 major approaches to adult speech production are reviewed. Strengths and weaknesses are evaluated with respect to developmental patterns. A developmental approach is then pursued. The strengths of existing theories are borrowed, and the ideas are resynthesized under the working hypothesis. The speech production process is then reimagined in developmental stages, with each stage building on the previous one. Conclusion The resulting theory proposes that speech production relies on conceptually linked representations that are information-reduced holistic perceptual and motoric forms, constituting the phonological aspect of a system that is acquired with the lexicon. These forms are referred to as exemplars and schemas, respectively. When a particular exemplar and schema are activated with the selection of a particular lexical concept, their forms are used to define unique trajectories through an endogenous perceptual-motor space that guides implementation. This space is not linguistic, reflecting its origin in the prespeech period. Central feedback control over production emerges with failures in communication and the development of a self-concept.
Topics: Adult; Child; Child Language; Human Development; Humans; Models, Theoretical; Phonetics; Speech
PubMed: 31465709
DOI: 10.1044/2019_JSLHR-S-CSMC7-18-0130 -
Developmental Biology Sep 2024Regeneration, regrowing lost and injured body parts, is an ability that generally declines with age or developmental transitions (i.e. metamorphosis, sexual maturation)....
Regeneration, regrowing lost and injured body parts, is an ability that generally declines with age or developmental transitions (i.e. metamorphosis, sexual maturation). Regeneration is also an energetically costly process, and trade-offs occur between regeneration and other costly processes such as growth, or sexual reproduction. Here we investigate the interplay of regeneration, reproduction, and developmental stage in the segmented worm Platynereis dumerilii. P. dumerilii can regenerate its whole posterior body axis, along with its reproductive cells, thereby having to carry out the two costly processes (somatic and germ cell regeneration) after injury. We specifically examine how developmental stage affects the success of germ cell regeneration and sexual maturation in developmentally young versus developmentally old organisms. We hypothesized that developmentally younger individuals (i.e. with gametes in early mitotic stages) will have higher regeneration success than the individuals at developmentally older stages (i.e. with gametes undergoing meiosis and maturation). Surprisingly, older amputated worms grew faster and matured earlier than younger amputees. To analyze germ cell regeneration during and after posterior regeneration, we used Hybridization Chain Reaction for the germline marker vasa. We found that regenerated worms start repopulating new segments with germ cell clusters as early as 14 days post amputation. In addition, vasa expression is observed in a wide region of newly-regenerated segments, which appears different from expression patterns during normal growth or regeneration in worms before gonial cluster expansion.
Topics: Animals; Germ Cells; Regeneration; Sexual Maturation; Polychaeta
PubMed: 38797257
DOI: 10.1016/j.ydbio.2024.05.013 -
Current Diabetes Reviews 2015Developmentally-tailored diabetes self-care education and support are integral parts of contemporary multidisciplinary T1D care. The patient with T1D must have the... (Review)
Review
Developmentally-tailored diabetes self-care education and support are integral parts of contemporary multidisciplinary T1D care. The patient with T1D must have the support of the family and the diabetes team to maintain the rigors of diabetes management, but the specific roles of patients and families with regard to daily diabetes tasks change considerably throughout the developmental span of early childhood, middle childhood/school-age years, and adolescence. This review provides a framework of key normative developmental issues for each of these developmental stages. Within this context, ideal family diabetes management is reviewed within each developmental stage and anticipated challenges that can arise during these stages and that can adversely impact diabetes management are presented. This paper also summarizes empirical evidence for specific intervention and care strategies to support optimal diabetes management across these stages in order to maximize opportunities for a successful transfer of diabetes management tasks from parents to maturing youth. Finally, the review provides an emphasis on approaches to promote family teamwork and adolescent diabetes self-care adherence as well as opportunities to use novel technology platforms as a means to support optimal diabetes management.
Topics: Adolescent; Adolescent Behavior; Adolescent Development; Age Factors; Child; Child Behavior; Child Development; Child, Preschool; Diabetes Mellitus, Type 1; Family Relations; Health Behavior; Health Knowledge, Attitudes, Practice; Humans; Infant; Infant, Newborn; Self Care; Treatment Outcome; Young Adult
PubMed: 25901503
DOI: 10.2174/1573399811666150421114146 -
Animal Science Journal = Nihon Chikusan... Jan 2019Chickens and Japanese quail (Coturnix japonica) have traditionally been the primary avian models in developmental biology research. Recently, the blue-breasted quail...
Chickens and Japanese quail (Coturnix japonica) have traditionally been the primary avian models in developmental biology research. Recently, the blue-breasted quail (Coturnix chinesis), the smallest species in the order Galliformes, has been proposed as an excellent candidate model in avian developmental studies owing to its precocious and prolific properties. However, data on the embryonic development of blue-breasted quail are scarce. Here, we developed a normal developmental series for the blue-breasted quail based on developmental features. The blue-breasted quail embryos take 17 days to reach the hatching period at 37.7°C. We documented specific periods of incubation in which significant development occurred, and created a 39-stage developmental series. The developmental series for the blue-breasted quail was almost identical to that for chickens and Japanese quail in the earlier stages of development (stages 1-16). Our staging series is especially useful at later stages of development (stages 34-39) of blue-breasted quail embryos as a major criterion of staging in this phase of development was the weight of embryos and the length of third toes.
Topics: Animals; Coturnix; Embryo Culture Techniques; Embryonic Development; Time Factors
PubMed: 30370683
DOI: 10.1111/asj.13119 -
Journal of the American Academy of... Jan 2024As children age, there are set milestones that we follow clinically to help track fine motor, gross motor, social, and language development. Because we know what a...
As children age, there are set milestones that we follow clinically to help track fine motor, gross motor, social, and language development. Because we know what a 2-month-old vs 4-month-old vs 1-year-old child should be able to do, we are able to assess whether a given child is on track developmentally. In pediatrics, three developmental stages are assessed and, if, behind there is a clear next step, often to involve early intervention. In child psychiatry, work has been done to establish stages of development as well, seen through the work of Piaget, Erickson, and others. These stages help to define the thoughts and behaviors expected for different-aged children, and thus can help with putting together our diagnostic formulation. The difficulty is that these stages are much broader temporally then the early motor, social, and language developmental milestones. Students may also be participating in the same experiences, such as the same grade level, even though they are at different developmental levels based on their age when they started school, as there could be as much as a year difference between those in a given grade. This has led to concerns about being able to distinguish a child struggling with attention-deficit/hyperactivity disorder (ADHD) relative to a child who is younger than his peers, as teachers may compare a young child to their older peers when filling out assessment forms. These are the developmental questions that we often must ponder as child psychiatrists, inasmuch as mental health and behavioral development are complex and influenced by many factors. In this month's Book Forum, Rishab Chawla looks more into these questions in the review of Nasty, Brutish and Short by Scott Hershovitz, pointing out that there is an overlap between the skills of a child psychiatrist to assess the behavioral impact of these developmental questions and the philosophical questions that younger children start to ponder. The child's developmental understanding of right and wrong will better help us to assess the behaviors that present to us in the office. As Rishab points out in the review, we must ask more about these children whom we see regarding these philosophical questions to better understand some of the behaviors present. Looking more deeply into a student's understanding of these questions may better help us to distinguish developmentally appropriate or inappropriate behaviors.
Topics: Child; Humans; Aged; Infant; Attention Deficit Disorder with Hyperactivity; Schools; Mental Health; Peer Group
PubMed: 37805068
DOI: 10.1016/j.jaac.2023.09.542 -
Tijdschrift Voor Psychiatrie 2012On the basis of our current knowledge, developmental disorders can be divided into the following stages: stage 0: normal variation, stage 1: simple disorder of moderate... (Review)
Review
BACKGROUND
On the basis of our current knowledge, developmental disorders can be divided into the following stages: stage 0: normal variation, stage 1: simple disorder of moderate severity, stage 2: complicating co-morbidity and/or harmful background circumstances, and stage 3: serious disorder with harmful background circumstances.
AIM
To describe the current views on prognostic aspects of staging from a developmental perspective.
METHOD
The study is based on a critical review of the relevant literature.
RESULTS
The current division into stages is still insufficiently predictive, partly because development is a flexible process with risks, chances and second chances. All psychiatric disorders are in essence developmental disorders that arise in the course of development as a result of the interaction between predisposition and background circumstances. As from the very first meiosis the hereditary predisposition is subject to influences in the womb environment. The forming of networks in the brain, the distribution of neurotransmitters and the neurological profile are influenced by the genetic potential for chances and risks and are all a result of interactions. This complicated developmental history raises questions about the specificity of current clinical syndromes.
CONCLUSION
In time there is likely to be a much more accurate staging system. This will come about if, as a result of the analysis of large pooled databases, it becomes possible to make a better assessment of the relative risks of genetic configurations, brain connections, stress regulation in the brain, neuropsychological profiles and behavioural and emotional forms of expression in the light of the interactions that occur with the aforementioned background circumstances.
Topics: Adaptation, Psychological; Child; Child Development Disorders, Pervasive; Developmental Disabilities; Diagnosis, Differential; Diagnostic and Statistical Manual of Mental Disorders; Genetic Predisposition to Disease; Humans; Prognosis; Risk Factors; Social Environment; Treatment Outcome
PubMed: 23138624
DOI: No ID Found -
Journal of Cell Science Sep 2009Recognition of polyubiquitylated substrates by the proteasome is a highly regulated process that requires polyubiquitin receptors. We show here that the concentrations...
Recognition of polyubiquitylated substrates by the proteasome is a highly regulated process that requires polyubiquitin receptors. We show here that the concentrations of the proteasomal and extraproteasomal polyubiquitin receptors change in a developmentally regulated fashion. The stoichiometry of the proteasomal p54/Rpn10 polyubiquitin receptor subunit, relative to that of other regulatory particle (RP) subunits falls suddenly at the end of embryogenesis, remains low throughout the larval stages, starts to increase again in the late third instar larvae and remains high in the pupae, adults and embryos. A similar developmentally regulated fluctuation was observed in the concentrations of the Rad23 and Dsk2 extraproteasomal polyubiquitin receptors. Depletion of the polyubiquitin receptors at the end of embryogenesis is due to the emergence of a developmentally regulated selective proteolytic activity. To follow the fate of subunit p54/Rpn10 in vivo, transgenic Drosophila melanogaster lines encoding the N-terminal half (NTH), the C-terminal half (CTH) or the full-length p54/Rpn10 subunit were established in the inducible Gal4-UAS system. The daughterless-Gal4-driven whole-body expression of the full-length subunit or its NTH did not produce any detectable phenotypic changes, and the transgenic products were incorporated into the 26S proteasome. The transgene-encoded CTH was not incorporated into the 26S proteasome, caused third instar larval lethality and was found to be multi-ubiquitylated. This modification, however, did not appear to be a degradation signal because the half-life of the CTH was over 48 hours. Accumulation of the CTH disturbed the developmentally regulated changes in subunit composition of the RP and the emergence of the selective proteolytic activity responsible for the depletion of the polyubiquitin receptors. Build-up of subunit p54/Rpn10 in the RP had already started in 84-hour-old larvae and reached the full complement characteristic of the non-larval developmental stages at the middle of the third instar larval stage, just before these larvae perished. Similar shifts were observed in the concentrations of the Rad23 and Dsk2 polyubiquitin receptors. The postsynthetic modification of CTH might be essential for this developmental regulation, or it might regulate an essential extraproteasomal function(s) of subunit p54/Rpn10 that is disturbed by the expression of an excess of CTH.
Topics: Animals; Drosophila Proteins; Drosophila melanogaster; Gene Expression Regulation, Developmental; Polyubiquitin
PubMed: 19654212
DOI: 10.1242/jcs.049049 -
ISRN Addiction 2013At least by informal design, tobacco and other drug abuse prevention programs are tailored to human developmental stage. However, few papers have been written to examine...
At least by informal design, tobacco and other drug abuse prevention programs are tailored to human developmental stage. However, few papers have been written to examine how programming has been formulated as a function of developmental stage throughout the lifespan. In this paper, I briefly define lifespan development, how it pertains to etiology of tobacco and other drug use, and how prevention programming might be constructed by five developmental stages: (a) young child, (b) older child, (c) young teen, (d) older teen, and (e) adult (emerging, young-to-middle and older adult substages). A search of the literature on tobacco and other drug abuse prevention by developmental stage was conducted, and multiple examples of programs are provided for each stage. A total of 34 programs are described as examples of each stage (five-young children, 12-older children, eight-young teens, four-older teens, and five-adults). Implications for future program development research are stated. In particular, I suggest that programming continue to be developed for all stages in the lifespan, as opposed to focusing on a single stage and that developmentally appropriate features continues to be pursued to maximize program impact.
PubMed: 25298961
DOI: 10.1155/2013/745783