Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Body Patterning”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,675 records · Page 93Linked to original sources
PubMed2005

Dorsoventral patterning of the Xenopus eye: a collaboration of Retinoid, Hedgehog and FGF receptor signaling.

In the developing spinal cord and telencephalon, ventral patterning involves the interplay of Hedgehog (Hh), Retinoic Acid (RA) and Fibroblast Growth Factor (FGF) signaling. In the eye, ventral specification involves Hh signaling, but the roles of RA and FGF signaling are less clear. By overexpression assays in Xenopus embryos, we found that both RA and FGF receptor (FGFR) signaling ventralize the eye, by expanding optic stalk and ventral retina, and repressing dorsal retina character. Co-overexpression experiments show that RA and FGFR can collaborate with Hh signaling and reinforce its ventralizing activity. In loss-of-function experiments, a strong eye dorsalization was observed after triple inhibition of Hh, RA and FGFR signaling, while weaker effects were obtained by inhibiting only one or two of these pathways. These results suggest that the ventral regionalization of the eye is specified by interactions of Hh, RA and FGFR signaling. We argue that similar mechanisms might control ventral neural patterning throughout the central nervous system.

Animals↗
PubMed1998

Sequential activation of the EGF receptor pathway during Drosophila oogenesis establishes the dorsoventral axis.

Previous work has demonstrated a role for the Drosophila EGF receptor (Torpedo/DER) and its ligand, Gurken, in the determination of anterioposterior and dorsoventral axes of the follicle cells and oocyte. The roles of DER in establishing the polarity of the follicle cells were examined further, by following the expression of DER-target genes. One class of genes (e.g. kekon) is induced by the DER pathway at all stages. Broad expression of kekon at the stage in which the follicle cells migrate posteriorly over the oocyte, demonstrates the capacity of the pathway to pattern all follicle cells except the ventral-most rows. This may provide the spatial coordinates for the ventral-most follicle cell fates. A second group of target genes (e.g. rhomboid (rho)) is induced only at later stages of oogenesis, and may require additional inputs by signals emanating from the anterior, stretch follicle cells. The function of Rho was analyzed by ectopic expression in the stretch follicle cells, and shown to induce a non-autonomous dorsalizing activity that is independent of Gurken. Rho thus appears to be involved in processing a DER ligand in the follicle cells, to pattern the egg chamber and allow persistent activation of the DER pathway during formation of the dorsal appendages.

Animals↗
PubMed1998

Equivalence in the genetic control of hindbrain segmentation in fish and mouse.

The vertebrate hindbrain is subdivided into a series of rhombomeres whose segmental organization serves to pattern the architecture and innervation of the developing head. The zebrafish gene valentino is required cell-autonomously in the development of rhombomeres 5 and 6, and valentino mutants lack visible hindbrain segmentation caudal to the r3/4 boundary (Moens, C. B., Yan, Y.-L., Appel, B., Force, A. G., and Kimmel, C. B. (1996) Development 122, 3981-3990). Here we show that valentino is the zebrafish homologue of the mouse segmentation gene kreisler, which encodes a bZip transcription factor. The valentino gene is expressed in a manner consistent with its proposed role in subdividing rhombomeres 5 and 6 from their common precursor 'proto-segment' in the presumptive hindbrain, a process that we also demonstrate is reflected in the normal order of appearance of rhombomere boundaries. As well as having similar phenotypes with respect to visible hindbrain segmentation and patterns of marker gene expression, valentino and kreisler mutants have similar pharyngeal arch and inner ear defects, consistent with a conserved role for this gene in hindbrain segmentation and in patterning of the head periphery.

Amino Acid Sequence↗
PubMed1999

SF/HGF is a mediator between limb patterning and muscle development.

Scatter factor/hepatocyte growth factor (SF/HGF) is known to be involved in the detachment of myogenic precursor cells from the lateral dermomyotomes and their subsequent migration into the newly formed limb buds. As yet, however, nothing has been known about the role of the persistent expression of SF/HGF in the limb bud mesenchyme during later stages of limb bud development. To test for a potential role of SF/HGF in early limb muscle patterning, we examined the regulation of SF/HGF expression in the limb bud as well as the influence of SF/HGF on direction control of myogenic precursor cells in limb bud mesenchyme. We demonstrate that SF/HGF expression is controlled by signals involved in limb bud patterning. In the absence of an apical ectodermal ridge (AER), no expression of SF/HGF in the limb bud is observed. However, FGF-2 application can rescue SF/HGF expression. Excision of the zone of polarizing activity (ZPA) results in ectopic and enhanced SF/HGF expression in the posterior limb bud mesenchyme. We could identify BMP-2 as a potential inhibitor of SF/HGF expression in the posterior limb bud mesenchyme. We further demonstrate that ZPA excision results in a shift of Pax-3-positive cells towards the posterior limb bud mesenchyme, indicating a role of the ZPA in positioning of the premuscle masses. Moreover, we present evidence that, in the limb bud mesenchyme, SF/HGF increases the motility of myogenic precursor cells and has a role in maintaining their undifferentiated state during migration. We present a model for a crucial role of SF/HGF during migration and early patterning of muscle precursor cells in the vertebrate limb.

Animals↗
PubMed2002

Healthy Growth: project description and baseline findings.

OBJECTIVES: The purpose of the study was to describe the physical activity, blood pressure, and body fat patterns of sixth-grade, African-American girls (N = 82), who participated in the Healthy Growth Study. The purpose of the primary study questions was to determine which sets of variables best predict blood pressure, physical activity, and body fat. DESIGN AND METHODS: This paper is a cross sectional analysis of the first assessment of a 5-year longitudinal project. Standard procedures were used to assess height, weight, skinfolds, blood pressure, physical activity, predictors of physical activity, maturation, dietary intake, fitness level, and health behaviors. RESULTS: The average age of the subjects was 12.3 years; almost two-thirds of the girls had reached menarche. Fifty-two percent of the 13-year-olds had body mass index (BMI) values greater than the 85th percentile for their age and sex compared to 32% of the 12-year-olds. None of the variables were significantly related to diastolic or systolic blood pressure. Physical activity was significantly and negatively related to total percent of calories from fat and to breast stages and positively related to waist/thigh ratio. Body mass index (BMI) was significantly and positively related to breast stages. CONCLUSIONS: Important developmental differences between 12- and 1 3-year-olds were evident. Body mass index (BMI) was mainly dependent on physical maturity. No relationship was found between BMI and blood pressure. The relationship between physical activity and waist/thigh ratio merits further study. The importance of BMI and physical inactivity as potential indicators of cardiovascular risk in adolescent girls is discussed. Developmentally appropriate and culturally competent interventions are recommended to increase physical activity and healthy eating behaviors among adolescents.

Adolescent↗
PubMed1989

Dietary and exercise practices of college-aged female bodybuilders.

The college-aged female bodybuilders in this study consumed nutrient-dense, low-fat foods and participated in strenuous exercise to develop their physiques. Non-competitors maintained consistent energy intake, exercise patterns, and body weight throughout the study period. In contrast, competitors exhibited periods of caloric restriction and excess associated with the pre- and post-competition events. This study indicates that college-aged female bodybuilders have food intake and exercise patterns that are unique to the sport.

Adult↗
PubMed1995

Smoking and its effects on maternal body composition in late pregnancy.

OBJECTIVE: To assess the possible impact of smoking on body composition at the 34-39 weeks of pregnancy, and its consequences on birth weight. SUBJECTS: 31 smokers and 31 non-smokers matched by age, gestational age and percentage of standard weight (PSW). Smoking mothers had 5 cigarettes or more per day during the whole period of pregnancy and non-smoking mothers never smoked. METHODS: A cross-sectional study was conducted in an urban Public Health Center. Anthropometry and the deuterium dilution technique were used to determine body composition. The statistical analysis used a t-test for matched pairs to assess significance of the means difference for each variable. RESULTS: Suprailiac and subscapular skinfolds were found to be larger in non-smokers; this difference was significant for the suprailiac skinfold (P < 0.05). No significant difference was found in total body fat, total body water and fat-free mass obtained with the deuterium dilution technique, or FFM determined by anthropometry. Infants' birth weight was similar in the two groups of mothers. CONCLUSION: These findings suggest that pregnancy does not modify the pattern of body fat distribution already present in smokers before conception. Infants' birth weight was similar in both groups, probably due to no difference in fat-free mass and body fat. The physiological effect of nicotine (e.g. on prolactin, micronutrients), seems to be clearer during lactation and infant growth.

Adult↗
PubMed1994

Obesity, body fat distribution, and blood pressure in Nigerian and African-American men and women.

This article describes a study that assesses body fat distribution patterns in Nigerian and African-American males and females and determines the association between body fat distribution patterns and blood pressure in young adults of differing geographical and ethnic backgrounds. The study population was comprised of 275 African Americans (92 males and 183 females) and 282 Nigerians (219 males and 63 females). The mean ages for the African-American males and females were 18.7 and 18.9 years, respectively, compared with 21 and 19.2 years for the Nigerian males and females. African Americans were more likely to be obese and overweight compared with their Nigerian counterparts. However, there were no significant differences between the two ethnic groups within gender for body fat distribution patterns based on waist-to-hip ratio. Despite being leaner, the Nigerians had higher diastolic blood pressures than the African Americans. There were no significant associations observed between blood pressure and waist-to-hip ratio for either the Nigerian or the African-American males or females, and body mass index was associated consistently with blood pressure only among the African Americans. These findings suggest that body mass index, a general indicator of obesity, is a better correlate of blood pressure than the waist-to-hip ratio among African Americans.

Adipose Tissue↗
PubMed2002

Spatial representation of the glomerular map in the Drosophila protocerebrum.

In the fruit fly, Drosophila, olfactory sensory neurons expressing a given receptor project to spatially invariant loci in the antennal lobe to create a topographic map of receptor activation. We have asked how the map in the antennal lobe is represented in higher sensory centers in the brain. Random labeling of individual projection neurons using the FLP-out technique reveals that projection neurons that innervate the same glomerulus exhibit strikingly similar axonal topography, whereas neurons from different glomeruli display very different patterns of projection in the protocerebrum. These results demonstrate that a topographic map of olfactory information is retained in higher brain centers, but the character of the map differs from that of the antennal lobe, affording an opportunity for integration of olfactory sensory input.

Animal Structures↗
PubMedDate not supplied

The influence of obesity on chronic venous disease.

The authors investigate the impact of overweight in patients with chronic venous disease and determine if the eventual effect can be explained by increased venous reflux alone. Patients with chronic venous disease who underwent duplex-ultrasound scanning at the Vascular Center, Straub Clinic and Hospital during 1999 were classified according to the clinical, etiologic, anatomic, and pathophysiologic (CEAP) system and body mass index (kg/m(2)) was calculated. Reflux duration was measured in seconds and peak reverse flow velocity in cm/second. Multi-segment reflux score (total score) was calculated for both reflux duration and peak reverse flow velocity. The reflux pattern and body mass index were correlated to the clinical presentation. Four hundred and one lower extremities (204 right, 197 left) in 272 patients (173 female) with a mean age of 60 years (range 14-90) were investigated. The mean body mass index was 28.9 (+/-7.76). One hundred sixty-seven patients (61%) were overweight (body mass index 25 kg/m(2) or more). There was a significant association between body mass index and the clinical severity (p<0.001). This association persisted after adjustments for total peak reverse flow velocity and total reflux score were made (p<0.001). Overweight patients were more likely to have skin changes and ulceration (p<0.001) than patients with a body mass index less than 25 kg/m(2), despite similar values for total reflux time (p=0.92) and total peak reverse flow velocity (p=0.98). There was an ethnic difference, with Pacific Islanders being significantly heavier and younger compared to patients of white, Asian and Filipino ancestries. The variations in the frequency of skin changes were consistent with ethnic differences in body mass index. The correlation of body mass index with clinical severity independent of reflux measurements indicates that the effect of overweight may involve a mechanism separate from local effects on venous flow. Overweight appears to be a separate risk factor for increased severity of skin changes in patients with chronic venous disease.

Aged↗
PubMed1999

Identification of the t(15;17) in AML FAB types other than M3: evaluation of the role of molecular screening for the PML/RARalpha rearrangement in newly diagnosed AML. The Medical Research Council (MRC) Adult Leukaemia Working Party.

Acute promyelocytic leukaemia (APL) is characterized by the t(15;17) leading to the formation of PML-RARalpha and RARalpha-PML fusion genes; this rearrangement has been considered both diagnostic for, and restricted to, this subtype of acute myeloid leukaemia (AML FAB M3). We describe two cases of AML with the t(15;17) associated with a PML/RARalpha rearrangement which lacked typical APL morphology, classified as FAB M1 and M2 respectively. In both cases morphological review revealed small populations of cells which exhibited some features associated with APL. In the case classified as M1, PML immunofluorescence studies revealed the classic microparticulate nuclear staining pattern as observed in typical cases of APL with the t(15;17). Similarly, blasts from this case were found to be sensitive to ATRA in vitro as determined by NBT reduction test and by normalization of the PML nuclear body staining pattern. To determine the frequency of PML/RARalpha rearrangements in FAB subtypes other than M3, 530 patients from the MRC AML trials were screened using nested RT-PCR. Only one individual, initially classified as M5 with a normal karyotype, was found to have a PML/RARalpha rearrangement. The diagnosis was revised to M3 variant on subsequent morphological review. In conclusion, this study demonstrates that, in rare cases, the t(15;17) is not restricted to patients with M3 morphology as defined by current FAB criteria. Therefore, although we consider cytogenetic analysis of newly diagnosed cases of AML to be mandatory, our data suggests that routine molecular screening for PML/RARalpha rearrangements is not justified and should be reserved for those cases displaying features which may be suspicious of APL even if such cells comprise only a minority of the total population.

Adolescent↗
PubMed2004

Understanding endothelin-1 function during craniofacial development in the mouse and zebrafish.

Morphogenesis of the face and neck is driven by an intricate relay of signaling molecules and transcription factors organized into hierarchical pathways. The coordinated action of these pathways regulates the development of neural crest cells within the pharyngeal arches, resulting in proper spatiotemporal formation of bone, cartilage, and connective tissue. While the functions of many genes involved in these processes were initially elucidated through the use of knockout technology in the mouse, increasing numbers of zebrafish craniofacial mutants have led to a rapid expansion in the identification of genes involved in craniofacial development. A comparative analysis of signaling pathways involved in these processes between mouse and zebrafish holds the potential not only to pinpoint conserved and therefore crucial gene functions in craniofacial development, but also to rapidly identify and study downstream effectors. These complementary approaches will also allow rapid identification of candidate genes and gene functions disrupted in human craniofacial dysmorphologies. In this brief review, we present a comparative analysis of one molecule involved in craniofacial development, endothelin-1, a small, secreted protein that is crucial for patterning the neural crest cells that give rise to lower jaw and throat structures.

Animals↗
PubMed2001

Development of GABA-immunoreactive neuron patterning in the spinal cord.

In the frog Xenopus laevis, gamma-aminobutyric acid (GABA)-immunoreactive spinal cord neurons (Kolmer-Agduhr cells) formed a dispersed pattern within two columns on either side of the midline. The cellular pattern became established during embryonic and larval development. The GABA-immunoreactive cells are cerebrospinal fluid (CSF)-contacting neurons that began to appear by 1.2 days (st 26) of development. This stage occurred shortly after neural tube closure (0.9 days, st 21) and followed the appearance of ultrastructural characteristics of CSF-contacting neurons. The pattern of GABA-immunoreactive cells emerged during embryogenesis, as their density increased. Each longitudinal column was heterogeneous, containing cells with and without GABA immunoreactivity. Spatial analysis at several embryonic and larval stages showed that the cells in each column formed a nonrandom, dispersed pattern even at early stages of differentiation. This one-dimensional pattern resembled that of dopamine-immunoreactive neurons, which are also located in the ventral spinal cord. The patterning of both cell types followed a different time course, but the ultimate spacing of the neurons remained comparable. These results suggested that the mechanism patterning the two cell types within the same region was similar but not identical and may involve related molecular mechanisms.

Aging↗
PubMed2004

PI3K inhibitors block skeletogenesis but not patterning in sea urchin embryos.

Skeletogenesis in the sea urchin embryo is a simple model of biomineralization, pattern formation, and cell-cell communication during embryonic development. The calcium carbonate skeletal spicules are secreted by primary mesenchyme cells (PMCs), but the skeletal pattern is dictated by the embryonic ectoderm. Although the process of skeletogenesis is well characterized, there is little molecular understanding of the basis of patterning within this system. In this study, we examined the contribution of phosphatidylinositide 3-kinase (PI3K)-mediated signaling to the skeletogenic process in sea urchin embryos by using the well-established PI3K inhibitors LY294002 and wortmannin. Our results show that PI3K inhibitors specifically and reversibly block skeletogenesis, and that this blockade occurs within the PMCs rather than in the ectoderm, because the inhibitors block spiculogenesis in cultured micromeres. Our results are consistent with a model in which PI3K signaling is required, not for pattern sensing or interpretation but rather for the biomineralization process itself in the sea urchin embryo.

Androstadienes↗
PubMed2002

Retina dorsal/ventral patterning by Xenopus TBX3.

Although it is well known that patterning in the retina of vertebrates is essential for retina formation and for the retinotopic projection of axons in the embryo, knowledge of molecular and cellular mechanisms of retina patterning is limited. We have previously identified the Xenopus Tbx3 gene (XTbx3) which is expressed in the dorsal retina but not in the ventral retina in Xenopus embryos [H. Li, C. Tierney, L. Wen, J. Y. Wu, and Y. Rao (1997) Development 124, 603-615; M.-L. He, L. Wen, C. E. Campbell, J. Y. Wu, and Y. Rao (1999) Proc. Natl. Acad. Sci. USA 96, 10212-10217]. Dosage-sensitive phenotypes in humans suggest that the manipulation of the amount and location of its products could be informative for understanding its normal function. Here we report that ectopic expression of Tbx3 by mRNA injection suppressed formation of the ventral retina. Furthermore, Tbx3 injection led to inhibition of molecular markers for the ventral retina including Pax-2 and netrin, indicating that Tbx3 plays an important role in retina dorsal/ventral patterning in vertebrates by inhibition of gene expression for ventral retina specification.

Animals↗
PubMed1997

A role for midline closure in the reestablishment of dorsoventral pattern following dorsal hindbrain ablation.

The cellular and molecular study of dorsal neural tube ablation reported here demonstrates a critical role for midline closure in hindbrain repatterning. This was revealed by detailed analysis of the transcriptional response of two genes, Pax-3 and slug, during repair of the neural tube following ablation. The reexpression of Pax-3 appears to rely on a single surface ectoderm/neuroepithelial contact, while this is insufficient for reexpression of slug. In fact, slug up-regulation only occurred upon midline closure and, strikingly, corresponded to down-regulation of Pax-3. We examined whether a candidate dorsalizing molecule, Bmp-4, was responsible for this reciprocal regulation of Pax-3 and slug at midline closure. However, Bmp-4 was not reexpressed following ablation, indicating not only that it is not responsible for the observed repatterning but that it lies in regulatory pathways distinct from Pax-3 and slug. We additionally examined the expression of Pax-6, which, together with assessment of the pattern of cranial ganglia, roof plate morphology, and positioning of branchiomotor exit points, demonstrates that neural crest regeneration is accompanied by reestablishment of a normal dorsoventral pattern within the neural tube. Thus, both local and longer range patterning appears to be restored following ablation, which is reliant dorsally on midline closure of the neural tube.

Animals↗
PubMed1997

Altered forebrain and hindbrain development in mice mutant for the Gsh-2 homeobox gene.

The patterning of the mammalian brain is orchestrated by a large battery of regulatory genes. Here we examine the developmental function of the Gsh-2 nonclustered homeobox gene. Whole-mount and serial section in situ hybridizations have been used to better define Gsh-2 expression domains within the developing forebrain, midbrain, and hindbrain. Gsh-2 transcripts are shown to be particularly abundant in the hindbrain and within the developing ganglionic eminences of the forebrain. In addition, mice carrying a targeted mutation of Gsh-2 have been generated and characterized. Homozygous mutants uniformly failed to survive more than 1 day following birth. At the physiologic level the mutants experienced apnea and reduced levels of hemoglobin oxygenation. Histologically, the mutant brains had striking alterations of discrete components. In the forebrain the lateral ganglionic eminence was reduced in size. In the hindbrain, the area postrema, an important cardiorespiratory chemosensory center, was absent. The contiguous nucleus tractus solitarius, involved in integrating sensory input to maintain homeostasis, was also severely malformed in mutants. Immunohistochemistry was used to examine the mutant brains for alterations in the distribution of markers specific for serotonergic and cholinergic neurons. In addition, in situ hybridizations were used to define expression patterns of the Dlx 2 and Nkx 2.1 homeobox genes in Gsh-2 mutant mice. The mutant lateral ganglionic eminences showed an abnormal absence of Dlx 2 expression. These results better define the genetic program of development of the mammalian brain, support neuromeric models of brain development, and further suggest similar patterning function for homeobox genes in phylogenetically diverse organisms.

Animals↗