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PubMed2006

[Various methods of dynamic functional analysis in human sciences and economics].

Including the temporal and developmental dimension into the measurement of human conduct is a fundamental concern for those who do research in natural surroundings. Observing an individual day after day may possibly give a more complete vision of how behavior works than measuring a group of individuals at a single time and analyzing the differences found among them. Unfortunately most of the tools allowing analyzing individual time series call for large numbers of repeated observations. Thus, practicable longitudinal research designs often do not involve either enough repeated measurements for traditional time series analyses nor either replicate enough individuals for traditional, large-sample analyses. Dynamic factor analysis is a rationale and procedure for both pooling relatively short time series information across limited numbers of participants and analyzing the pooled information for its dynamic, process-relevant elements. It is a merging of two important analytical tools - multivariate time series and the common factor model, from which it distinguishes itself mainly by the fact that in dynamic factor analysis, the values of the common factors can influence the values of the observed variables both concurrently and in delayed fashion. Dynamic factor analysis is actually a method which allows detecting structures in the time series as well as the relations between the series and the explanatory variables. We illustrate the different models used in psychology and social sciences, as well as in econometry and economics.

Economics↗
PubMed2006

Leaf hydraulics.

Leaves are extraordinarily variable in form, longevity, venation architecture, and capacity for photosynthetic gas exchange. Much of this diversity is linked with water transport capacity. The pathways through the leaf constitute a substantial (>or=30%) part of the resistance to water flow through plants, and thus influence rates of transpiration and photosynthesis. Leaf hydraulic conductance (K(leaf)) varies more than 65-fold across species, reflecting differences in the anatomy of the petiole and the venation architecture, as well as pathways beyond the xylem through living tissues to sites of evaporation. K(leaf) is highly dynamic over a range of time scales, showing circadian and developmental trajectories, and responds rapidly, often reversibly, to changes in temperature, irradiance, and water supply. This review addresses how leaf structure and physiology influence K(leaf), and the mechanisms by which K(leaf) contributes to dynamic functional responses at the level of both individual leaves and the whole plant.

Gases↗
PubMed2003

Applications of computerized adaptive testing (CAT) to the assessment of headache impact.

OBJECTIVE: To evaluate the feasibility of computerized adaptive testing (CAT) and the reliability and validity of CAT-based estimates of headache impact scores in comparison with 'static' surveys. METHODS: Responses to the 54-item Headache Impact Test (HIT) were re-analyzed for recent headache sufferers (n = 1016) who completed telephone interviews during the National Survey of Headache Impact (NSHI). Item response theory (IRT) calibrations and the computerized dynamic health assessment (DYNHA) software were used to simulate CAT assessments by selecting the most informative items for each person and estimating impact scores according to pre-set precision standards (CAT-HIT). Results were compared with IRT estimates based on all items (total-HIT), computerized 6-item dynamic estimates (CAT-HIT-6), and a developmental version of a 'static' 6-item form (HIT-6-D). Analyses focused on: respondent burden (survey length and administration time), score distributions ('ceiling' and 'floor' effects), reliability and standard errors, and clinical validity (diagnosis, level of severity). A random sample (n = 245) was re-assessed to test responsiveness. A second study (n = 1103) compared actual CAT surveys and an improved 'static' HIT-6 among current headache sufferers sampled on the Internet. Respondents completed measures from the first study and the generic SF-8 Health Survey; some (n = 540) were re-tested on the Internet after 2 weeks. RESULTS: In the first study, simulated CAT-HIT and total-HIT scores were highly correlated (r = 0.92) without 'ceiling' or 'floor' effects and with a substantial reduction (90.8%) in respondent burden. Six of the 54 items accounted for the great majority of item administrations (3603/5028, 77.6%). CAT-HIT reliability estimates were very high (0.975-0.992) in the range where 95% of respondents scored, and relative validity (RV) coefficients were high for diagnosis (RV = 0.87) and severity (RV = 0.89); patient-level classifications were accurate 91.3% for a diagnosis of migraine. For all three criteria of change, CAT-HIT scores were more responsive than all other measures. In the second study, estimates of respondent burden, item usage, reliability and clinical validity were replicated. The test-retest reliability of CAT-HIT was 0.79 and alternate forms coefficients ranged from 0.85 to 0.91. All correlations with the generic SF-8 were negative. CONCLUSIONS: CAT-based administrations of headache impact items achieved very large reductions in respondent burden without compromising validity for purposes of patient screening or monitoring changes in headache impact over time. IRT models and CAT-based dynamic health assessments warrant testing among patients with other conditions.

Computer Systems↗
PubMed1984

An essay on contemporary dynamic psychiatry.

Psychodynamic theory is less well understood than one would wish, especially because of the centrality of dynamic theories in understanding a host of psychiatric disorders. The key psychodynamic notion is that psychiatric symptoms can be explained as manifestations of an unconscious purpose or strategy. The theoretical term that best encompasses this notion is "intentionality", a theoretical option that has, in many psychiatric circumstances, the greatest predictive and explanatory powers. Other more or less loosely related dynamic theories are the theory of the Oedipus complex, developmental theory, the theory of transference and the extraclinical theory. New theoretical paradigms are currently competing for explanatory priority, a development which reflects a healthy maturity in psychodynamic science, and which may mean that a new and superordinate theoretical paradigm is about to emerge. At a time of theoretical ferment it is particularly important that the theoretical underpinning of dynamic psychiatry be clearly explicated and the author claims that theoretical role for intentionality.

Countertransference↗
PubMed2002

Asymmetric cell division: microtubule dynamics and spindle asymmetry.

Asymmetric cell division can produce daughter cells with different developmental fates and is often accompanied by a difference in cell size. A number of recent genetic and in vivo imaging studies in Drosophila and Caenorhabditis elegans have begun to elucidate the mechanisms underlying the rearrangements of the cytoskeleton that result in eccentrically positioned cleavage planes. As a result, we are starting to gain an insight into the complex nature of the signals controlling cytoskeletal dynamics in the dividing cell. In this commentary we discuss recent findings on how the mitotic spindle is positioned and on cleavage site induction and place them in the context of cell size asymmetry in different model organisms.

Animals↗
PubMed1993

Precursor lesions of Wilms tumor: clinical and biological implications.

Nephrogenic rests (NR) are persistent embryonal remnants in the kidney that are apparent precursors of Wilms tumor (WT). Nephroblastomatosis (Nbl) denotes multiple or diffuse NR. Two major categories of NR have been recognized to date, perilobar (PLNR) and intralobar (ILNR). A dynamic classification of NR according to their recognized developmental fates is presented. Dormancy, maturation, involution, hyperplastic overgrowth, and neoplastic induction are the common fates of NR. Hyperplastic NR are far more common than formerly recognized, and are frequently confused with WT, especially in cases of multicentric and bilateral tumors. Biopsy is of limited value in distinguishing hyperplastic NR from WT, and the use of surgery in cases of Nbl requires careful consideration, as its role can in many cases be reduced or supplanted due to the effectiveness of modern imaging techniques and chemotherapy. An understanding of the natural history of NR and Nbl is essential for rational patient care decisions, and is important for understanding the molecular biology of WT.

Humans↗
PubMed2006

The role of histone modifications in epigenetic transitions during normal and perturbed development.

Epigenetic mechanisms control eukaryotic development beyond DNA-stored information. DNA methylation, histone modifications and variants, nucleosome remodeling and noncoding RNAs all contribute to the dynamic make-up of chromatin under distinct developmental options. In particular, the great diversity of covalent histone tail modifications has been proposed to be ideally suited for imparting epigenetic information. While most of the histone tail modifications represent transient marks at transcriptionally permissive chromatin, some modifications appear more robust at silent chromatin regions, where they index repressive epigenetic states with functions also outside transcriptional regulation. Under-representation of repressive histone marks could be indicative of epigenetic plasticity in stem, young and tumor cells, while committed and senescent (old) cells often display increased levels of these more stable modifications. Here, we discuss profiles of normal and aberrant histone lysine methylation patterns, as they occur during the transition of an embryonic to a differentiated cell or in controlled self-renewal vs pro-neoplastic or metastatic conditions. Elucidating these histone modification patterns promises to have important implications for novel advances in stem cell research, nuclear reprogramming and cancer, and may offer novel targets for the combat of tumor cells, potentially leading to new diagnostic and therapeutic avenues in human biology and disease.

Animals↗
PubMed1982

On the development of the spinal cord of the clawed frog, Xenopus laevis. I. Morphogenesis and histogenesis.

The morphogenesis and histogenesis of the spinal cord of Xenopus were examined. The study encompasses the developmental period between stage 41 and stage 66 (stages according to Nieuwkoop and Faber 1967). This period can roughly be divided into three phases. From stage 50 up to stage 53 strong proliferation and rapid growth are the most striking features. This developmental phase is preceded and followed by less dynamic periods. From stage 41 up to stage 50 the rate of proliferation is relatively low. The numbers of cells in the matrix and in the mantle layer are very small. In the mantle layer two classes of early differentiated transient neurons can be distinguished: primitive giant sensory or Rohon-Beard cells and primitive motor neurons. From stage 46 onward the originally tube-shaped spinal cord swells at the thoracic level into a thoracic enlargement. After stage 50 the proliferation strongly increases until a maximum at stage 53. Concomitantly a considerable acceleration of growth takes place. The major part of the mitoses are always concentrated in the dorsal part of the matrix. From stage 51 onward the cervical and lumbar regions show much more mitoses than the thoracic part. Distinct cervical and lumbar enlargements develop and are going to mask the thoracic swelling of the cord. From stage 54 on proliferation continues on an increasingly low level. The period between stage 54 and stage 66 is characterized by differentiation of the spinal neuronal elements.

Animals↗
PubMed2003

Anticancer drug development at the US National Cancer Institute.

Anticancer drug discovery and development is a rapidly evolving field. Recent advances in molecular oncology and the effort to completely sequence the human genome has led to an explosion in our understanding of the mechanisms involved in the transformation and growth of malignant cells. This in turn has led to major changes in our approach to traditional drug discovery and development. A dynamic example of how genomics is affecting cancer developmental therapeutics is provided by the ongoing changes being implemented in the anticancer drug development program run by the US National Cancer Institute (NCI). This review summarizes the history of drug screening and development efforts at the NCI over the past five decades from its inception up to its current state emphasizing molecularly targeted therapies. These changes have not only had an impact on drug discovery, but they are also providing new paradigms for the design and conduct of preclinical and early clinical trials.

Animals↗
PubMed1999

Urodynamic evaluation in boys treated for posterior urethral valves.

This study describes the urodynamic findings in 22 patients with posterior urethral valves and discusses their association with urinary incontinence, age, mode of primary treatment, renal function, and changes in the upper tracts. The patients' ages ranged from 3 to 26 years and 27% were either adolescents or older. The urodynamic findings were categorized into 5 main patterns, although mixed patterns were also observed; (1) normal capacity and compliance with normal detrusor contractility (2/22 patients, 9.1%); (2) small-capacity, hypocompliant bladder (8/22 patients, 36.4%); (3) unstable bladder (2/22 patients, 9.1%); (4) large-capacity, hypotonic bladder with decreased detrusor contractility (2/22 patients, 9.1%); and (5) normal capacity and compliance but with decreased detrusor contractility (8/22 patients, 36.4%). More than one-half of the patients (57.1%) evacuated their bladders incompletely, and this seemed to be associated with post-treatment episodes of urinary-tract infection. The commonest symptom was daytime frequency, urgency, and leak with nocturnal enuresis, which urodynamically correlated with a small-capacity, hypocompliant or unstable bladder or to incomplete evacuation of the bladder, leading to significant post-void residue. Significant detrusor dysfunction was identified in 2 asymptomatic patients as well, emphasizing the need to perform a routine urodynamic work-up on all valve patients. Urodynamic properties seemed to be associated with age. Small, hypocompliant, and unstable bladders were almost always seen in prepubertal boys and in the first 5 years following undiversion, whereas large, hypotonic bladders with impaired contractility were seen in post-pubertal boys. While the current policy is to avoid high diversion, data in this study suggest that disorders of detrusor capacity, compliance, and contractility exist in children treated by primary valve ablation and vesicostomy and that abnormal detrusor dynamics seem to be a reflection of inherent developmental detrusor dysfunction consequent to congenital infravesical obstruction.

Adolescent↗
PubMed2004

CLIP-170 family members: a motor-driven ride to microtubule plus ends.

CLIP-170 family proteins regulate microtubule plus end dynamics. Two reports published in this issue of Developmental Cell show that Bik1 and tip1p, the CLIP-170-like proteins of budding and fission yeast, are carried to microtubule plus ends by kinesin motor proteins. These findings indicate a complex interplay between microtubule-associated proteins and suggest a novel mechanism by which kinesin proteins stabilize microtubules.

Carrier Proteins↗
PubMed2001

3D modelling of gene expression patterns.

The current genome-sequencing projects provide "word indices" of the book of life. A central post-genomic question will be how these words are three-dimensionally deployed in the generation of organism form. Gene expression studies of developing organisms contribute an increasing wealth of snapshot data on the activation of individual genes at selected locations and single moments in the developmental process. However, a comprehensive understanding of the dynamic activation of multiple genes and their functional role in controlling the 3D processes of collective cell behaviour, pattern formation and morphogenesis, requires special tools for a systematic description of spatio-temporal patterns of gene activation and the ensuing phenotypic effects. This article concentrates on new, computer-based tools for the 3D analysis of gene expression patterns in embryonic development and their use for the systematic establishment of comprehensive gene expression maps.

Animals↗
PubMed2001

Correlated patterns of neuron differentiation and Hox gene expression in the hindbrain: a comparative analysis.

Hindbrain neurons are organized into coherent subpopulations with characteristic projection patterns and functions. Many of these serve vital functions that have been conserved throughout the vertebrate radiation, but diversification to modified or highly specialized functions has also occurred. The differentiation of identifiable neuron groups in specific spatial domains must involve the regional expression of determinants within the hindbrain neuroepithelium. The Hox genes are involved in longitudinal regionalization of the neural tube, and their expression patterns in the hindbrain are closely related to the rhombomeres which partition the hindbrain into morphogenetic units. Hox gene expression also exhibits conserved patterning as well as phylogenetic variation. One plausible mechanism that may have contributed to evolutionary diversification in hindbrain neuron populations is therefore the emergence of species-specific differences in Hox gene expression. This article presents a comparative overview of the regional patterning of selected Hox genes and hindbrain neuron populations in several embryologically important species. Although tantalizing correlations exist, the relationship between Hox genes and neuronal patterning is complex, and complicated by dynamic features in each. Much more comparative and developmental data must be obtained before the link between Hox gene expression and hindbrain neuron patterning can be elucidated satisfactorily in an evolutionary context.

Animals↗
PubMed2003

Biocultural orchestration of developmental plasticity across levels: the interplay of biology and culture in shaping the mind and behavior across the life span.

The author reviews reemerging coconstructive conceptions of development and recent empirical findings of developmental plasticity at different levels spanning several fields of developmental and life sciences. A cross-level dynamic biocultural coconstructive framework is endorsed to understand cognitive and behavioral development across the life span. This framework integrates main conceptions of earlier views into a unifying frame, viewing the dynamics of life span development as occurring simultaneously within different time scales (i.e., moment-to-moment microgenesis, life span ontogeny, and human phylogeny) and encompassing multiple levels (i.e., neurobiological, cognitive, behavioral, and sociocultural). Viewed through this metatheoretical framework, new insights of potential interfaces for reciprocal cultural and experiential influences to be integrated with behavioral genetics and cognitive neuroscience research can be more easily prescribed.

Aging↗
PubMed2025

16S rRNA and Metagenomic Datasets of Gastrointestinal Microbiota in Fetal and 7-Day-Old Goat Kids.

The perinatal period (from late gestation to the neonatal stage) in ruminants is a critical phase for fetal organ maturation, where ecological succession of gastrointestinal microbial communities significantly impacts livestock production efficiency. However, research remains insufficient regarding the distribution patterns and functional annotation of microbial communities across different gastrointestinal compartments during this period. This study characterized early microbiota dynamics in Hutianshi Goats using 16S rRNA sequencing (4 fetal goats at 90 ± 10 gestational days) and metagenomics (3 7-day-old goat kids). The fetal goat group generated 852,694 valid reads, yielding 688,277 high-quality reads after chimera removal for downstream analysis. The 7-day-old goat kids group produced 1,081,588,182 final valid reads, after data processing and assembly, 8,561,345 contigs were generated. Gene prediction identified 6,095,352 genes. Multi-database annotations (NR, KEGG, CAZy, etc.) revealed functional potential and antimicrobial resistance traits. The public release of this dataset facilitates academic understanding of microbial community dynamics and host-microbe interactions during this developmental stage, providing both theoretical foundations and data resources for ruminant developmental biology and precision breeding regulation.

Animals↗
PubMed2002

bcl-2 overexpression promotes myocyte proliferation.

To determine the influence of Bcl-2 on the developmental biology of myocytes, we analyzed the population dynamics of this cell type in the heart of transgenic (TG) mice overexpressing Bcl-2 under the control of the alpha-myosin heavy chain promoter. TG mice and non-TG (wild type, WT) mice were studied at 24 days, 2 months, and 4 months after birth. Bcl-2 overexpression produced a significant increase in the percentage of cycling myocytes and their mitotic index. These effects were strictly connected to the expression of the transgene, as demonstrated in isolated myocytes. The formation of mitotic spindle and contractile ring was identified in replicating cells. These typical aspects of mitosis were complemented with the demonstration of karyokinesis and cytokinesis to provide structural evidence of cell division. Apoptosis was low at all ages and was not affected by Bcl-2. The higher cell replication rate in TG was conditioned by a decrease in the expression of the cell-cycle inhibitors, p21(WAF1) and p16(INK4a), and by an increase in Mdm2-p53 complexes. In comparison with WT, TG had 0.4 x 10(6), 0.74 x 10(6), and 1.2 x 10(6) more myocytes in the left ventricle at 24 days, 2 months, and 4 months, respectively. Binucleated myocytes were 12% and 25% larger in WT than in TG mice at 2 and 4 months of age. Taken together, these observations reveal a previously uncharacterized replication-enhancing function of Bcl-2 in myocytes in vivo in the absence of stressful conditions.

Animals↗
PubMed1999

Creative collaborations. Writers and editors.

Creativity, which the culture often depicts as a solitary enterprise, is almost always impacted or even dependent upon one or another aspect of a real relationship or an internalized object relationship. This paper utilizes the example of creative collaborations between writers and editors to illustrate aspects of co-creativity, co-construction, and mutual influence. It draws on Howard Gardner's observation, based on a series of biographical studies, that a creator during a time of artistic or intellectual breakthrough requires both an affective support system and a cognitive one. His observation echoes that of child researchers who emphasize that the contour of developmental lines depends not only on an internal dynamic but on interactions with significant others and on cultural and social influences as well. This paper describes both successful and problematic collaborations between writers and editors and demonstrates the strengths of such collaborations and some of their potential faultlines as well.

Creativity↗