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Journal of Anatomy Nov 2015Migratory failure of somitic cells is the commonest explanation for ventral body wall defects. However, the embryo increases ~ 25-fold in volume in the period that the...
Migratory failure of somitic cells is the commonest explanation for ventral body wall defects. However, the embryo increases ~ 25-fold in volume in the period that the ventral body wall forms, so that differential growth may, instead, account for the observed changes in topography. Human embryos between 4 and 10 weeks of development were studied, using amira reconstruction and cinema 4D remodeling software for visualization. Initially, vertebrae and ribs had formed medially, and primordia of sternum and hypaxial flank muscle primordium laterally in the body wall at Carnegie Stage (CS)15 (5.5 weeks). The next week, ribs and muscle primordium expanded in ventrolateral direction only. At CS18 (6.5 weeks), separate intercostal and abdominal wall muscles differentiated, and ribs, sterna, and muscles began to expand ventromedially and caudally, with the bilateral sternal bars fusing in the midline after CS20 (7 weeks) and the rectus muscles reaching the umbilicus at CS23 (8 weeks). The near-constant absolute distance between both rectus muscles and approximately fivefold decline of this distance relative to body circumference between 6 and 10 weeks identified dorsoventral growth in the dorsal body wall as determinant of the 'closure' of the ventral body wall. Concomitant with the straightening of the embryonic body axis after the 6th week, the abdominal muscles expanded ventrally and caudally to form the infraumbilical body wall. Our data, therefore, show that the ventral body wall is formed by differential dorsoventral growth in the dorsal part of the body.
Topics: Abdominal Muscles; Abdominal Wall; Hernia, Umbilical; Humans; Intercostal Muscles; Mesoderm; Ribs; Spine; Sternum
PubMed: 26467243
DOI: 10.1111/joa.12380 -
Bioengineering (Basel, Switzerland) Sep 2022The vascular smooth muscle is vital for regulating blood pressure and maintaining cardiovascular health, and the resident smooth muscle cells (SMCs) in blood vessel... (Review)
Review
The vascular smooth muscle is vital for regulating blood pressure and maintaining cardiovascular health, and the resident smooth muscle cells (SMCs) in blood vessel walls rely on specific mechanical and biochemical signals to carry out these functions. Any slight change in their surrounding environment causes swift changes in their phenotype and secretory profile, leading to changes in the structure and functionality of vessel walls that cause pathological conditions. To adequately treat vascular diseases, it is essential to understand how SMCs crosstalk with their surrounding extracellular matrix (ECM). Here, we summarize in vivo and traditional in vitro studies of pathological vessel wall remodeling due to the SMC phenotype and, conversely, the SMC behavior in response to key ECM properties. We then analyze how three-dimensional tissue engineering approaches provide opportunities to model SMCs' response to specific stimuli in the human body. Additionally, we review how applying biomechanical forces and biochemical stimulation, such as pulsatile fluid flow and secreted factors from other cell types, allows us to study disease mechanisms. Overall, we propose that in vitro tissue engineering of human vascular smooth muscle can facilitate a better understanding of relevant cardiovascular diseases using high throughput experiments, thus potentially leading to therapeutics or treatments to be tested in the future.
PubMed: 36134994
DOI: 10.3390/bioengineering9090449 -
The Journal of Neuroscience : the... Oct 2019In 1954, Penfield and Jasper's findings based on electric stimulation of epileptic patients led them to hypothesize that a sensory representation of the body should be...
In 1954, Penfield and Jasper's findings based on electric stimulation of epileptic patients led them to hypothesize that a sensory representation of the body should be found in the precuneus. They termed this representation the "supplementary sensory" area and emphasized that the exact form of this homunculus could not be specified on the basis of their results. In the decades that followed, their prediction was neglected. The precuneus was found to be involved in numerous motor, cognitive and visual processes, but no work was done on its somatotopic organization. Here, we used a periodic experimental design in which 16 human subjects (eight women) moved 20 body parts to investigate the possible body part topography of the precuneus. We found an anterior-to-posterior, dorsal-to-ventral, toes-to-tongue gradient in a mirror orientation to the SMA. When inspecting body-part-specific functional connectivity, we found differential connectivity patterns for the different body parts to the primary and secondary motor areas and parietal and visual areas, and a shared connectivity to the extrastriate body area, another topographically organized area. We suggest that a whole-body gradient can be found in the precuneus and is connected to multiple brain areas with different connectivity for different body parts. Its exact role and relations to the other known functions of the precuneus such as self-processing, motor imagery, reaching, visuomotor and other body-mind functions should be investigated. Using fMRI, as well as sensitive spectral analysis, we found a new homunculus in the precuneus: an anterior-to-posterior, dorsal-to-ventral, toes-to-tongue somatotopic gradient in a mirror orientation to the SMA. When inspecting body-part-specific functional connectivity, we found differential connectivity patterns for the different body parts to the primary and secondary motor areas, parietal and visual areas, and a shared connectivity to the extrastriate body area, another topographically organized area. We suggest that a whole-body gradient can be found in the precuneus and is connected to multiple brain areas in a body-part-specific manner.
Topics: Adult; Brain Mapping; Evoked Potentials; Female; Humans; Magnetic Resonance Imaging; Male; Motor Cortex; Movement; Neural Pathways; Parietal Lobe; Psychomotor Performance; Sensation; Visual Cortex
PubMed: 31405923
DOI: 10.1523/JNEUROSCI.0727-18.2019 -
Frontiers in Sports and Active Living 2022Race time can be shortened by improving turn performance in competitive swimming, but this requires insight into the optimal turn technique. The aim of the present study...
Race time can be shortened by improving turn performance in competitive swimming, but this requires insight into the optimal turn technique. The aim of the present study was to examine the effect of Wall Contact Time (WCT) and Tuck Index on tumble turn performance and their interrelations by experimentally manipulating both variables, which has not been done in previous research. Eighteen Dutch national level swimmers (FINA points 552 ± 122) performed tumble turns with three different WCTs (shorter, preferred, longer) and three different Tuck Indices (higher, preferred, lower), which were recorded by four underwater cameras and a wall-mounted force plate. Linear kinematic and kinetic variables, including the approach velocity (V), wall adaptation time (T), percentage of active WCT (aWCT), peak push-off force (F) and exit velocity (V), were extracted from the recordings and analyzed statistically, using the 5 m round trip time (5mRTT) as performance measure. The results indicated that the WCT should be sufficiently long to generate a high push-off force at the end of wall contact when the body is in a streamlined position. This led to a significantly shorter 5mRTT than a shorter or longer WCT. A linear mixed effect model yielded negative significant effects of WCT (-4.22, < 0.001), F (-2.18, = 0.04), V (-4.83, = 0.02), T (-2.68, = 0.002), and V (-9.52, < 0.001) on the 5mRTT. The best overall turning performance was achieved with a Tuck Index of 0.7, which suggests that some of the participating swimmers could benefit from adapting their distance to the wall while turning, as was exemplified by calculating the optimal Tuck Index for individual swimmers. These results underscore the importance of WCT and Tuck Index vis-à-vis tumble turn performance, as well as their interrelations with other performance determining variables in this regard.
PubMed: 35935061
DOI: 10.3389/fspor.2022.936695 -
Nature Machine Intelligence Feb 2021The ability to propel against flows, i.e., to perform positive rheotaxis, can provide exciting opportunities for applications in targeted therapeutics and non-invasive...
The ability to propel against flows, i.e., to perform positive rheotaxis, can provide exciting opportunities for applications in targeted therapeutics and non-invasive surgery. To date, no biocompatible technologies exist for navigating microparticles upstream when they are in a background fluid flow. Inspired by many naturally- occurring microswimmers such as bacteria, spermatozoa, and plankton that utilize the non-slip boundary conditions of the wall to exhibit upstream propulsion, here, we report on the design and characterization of self-assembled microswarms that can execute upstream motility in a combination of external acoustic and magnetic fields. Both acoustic and magnetic fields are safe to humans, non-invasive, can penetrate deeply into the human body, and are well-developed in clinical settings. The combination of both fields can overcome the limitations encountered by single actuation methods. The design criteria of the acoustically-induced reaction force of the microswarms, which is needed to perform rolling-type motion, are discussed. We show quantitative agreement between experimental data and our model that captures the rolling behaviour. The upstream capability provides a design strategy for delivering small drug molecules to hard-to-reach sites and represents a fundamental step toward the realization of micro- and nanosystem-navigation against the blood flow.
PubMed: 34258513
DOI: 10.1038/s42256-020-00275-x -
Molecular Plant Mar 2012Secondary cell walls provide plants with rigidity and strength to support their body weight and ensure water and nutrient transport. They also provide textiles, timber,... (Review)
Review
Secondary cell walls provide plants with rigidity and strength to support their body weight and ensure water and nutrient transport. They also provide textiles, timber, and potentially second-generation biofuels for human use. Genes responsible for synthesis of the different cell wall components, namely cellulose, hemicelluloses, and lignin, are coordinately expressed and under transcriptional regulation. In the past several years, cell wall-related NAC and MYB transcription factors have been intensively investigated in different species and shown to be master switches of secondary cell wall biosynthesis. Positive and negative regulators, which function upstream of NAC master switches, have also been identified in different plant tissues. Further elucidation of the regulatory mechanisms of cell wall synthesis will facilitate the engineering of plant feedstocks suitable for biofuel production.
Topics: Cell Wall; Feedback, Physiological; Humans; Lignin; Transcription Factors
PubMed: 22138968
DOI: 10.1093/mp/ssr098 -
Microorganisms Sep 2020Non-tuberculous mycobacteria (NTM) are paradigmatic colonizers of the total environment, circulating at the interfaces of the atmosphere, lithosphere, hydrosphere,... (Review)
Review
Non-tuberculous mycobacteria (NTM) are paradigmatic colonizers of the total environment, circulating at the interfaces of the atmosphere, lithosphere, hydrosphere, biosphere, and anthroposphere. Their striking adaptive ecology on the interconnection of multiple spheres results from the combination of several biological features related to their exclusive hydrophobic and lipid-rich impermeable cell wall, transcriptional regulation signatures, biofilm phenotype, and symbiosis with protozoa. This unique blend of traits is reviewed in this work, with highlights to the prodigious plasticity and persistence hallmarks of NTM in a wide diversity of environments, from extreme natural milieus to microniches in the human body. Knowledge on the taxonomy, evolution, and functional diversity of NTM is updated, as well as the molecular and physiological bases for environmental adaptation, tolerance to xenobiotics, and infection biology in the human and non-human host. The complex interplay between individual, species-specific and ecological niche traits contributing to NTM resilience across ecosystems are also explored. This work hinges current understandings of NTM, approaching their biology and heterogeneity from several angles and reinforcing the complexity of these microorganisms often associated with a multiplicity of diseases, including pulmonary, soft-tissue, or milliary. In addition to emphasizing the cornerstones of knowledge involving these bacteria, we identify research gaps that need to be addressed, stressing out the need for decision-makers to recognize NTM infection as a public health issue that has to be tackled, especially when considering an increasingly susceptible elderly and immunocompromised population in developed countries, as well as in low- or middle-income countries, where NTM infections are still highly misdiagnosed and neglected.
PubMed: 32916931
DOI: 10.3390/microorganisms8091380 -
Bioarchitecture 2014Three different genes each located on a different chromosome encode the heavy chains of nonmuscle myosin II in humans and mice. This review explores the functional... (Review)
Review
Three different genes each located on a different chromosome encode the heavy chains of nonmuscle myosin II in humans and mice. This review explores the functional consequences of the presence of three isoforms during embryonic development and beyond. The roles of the various isoforms in cell division, cell-cell adhesion, blood vessel formation and neuronal cell migration are addressed in animal models and at the cellular level. Particular emphasis is placed on the role of nonmuscle myosin II during cardiac and brain development, and during closure of the neural tube and body wall. Questions addressed include the consequences on organ development, of lowering or ablating a particular isoform as well as the effect of substituting one isoform for another, all in vivo. Finally the roles of the three isoforms in human diseases such as cancer as well as in syndromes affecting a variety of organs in humans are reviewed.
Topics: Animals; Cell Adhesion; Embryonic Development; Humans; Mice; Models, Animal; Morphogenesis; Myosin Type II; Neoplasms; Protein Isoforms
PubMed: 25098841
DOI: 10.4161/bioa.29766 -
Endokrynologia Polska 2016Menopause is associated with multiple health and metabolic consequences resulting from the decrease in estrogens level. Women at postmenopausal age are burdened with a... (Review)
Review
Menopause is associated with multiple health and metabolic consequences resulting from the decrease in estrogens level. Women at postmenopausal age are burdened with a higher risk of cardiovascular diseases, and the main cause of mortality in this group is ischemic heart disease. Estrogen deficiency is related, among other things, with frequent occurrence of dislipidemia, cessation of the beneficial effect of estrogens on the vascular wall, increase in body weight characterized by unfavourable redistribution of fatty tissue, with an increased amount of visceral fat and reduction of so-called non-fatty body mass. Estrogens exert an effect on metabolism, mainly through the genomic mechanism. The presence of α and β estrogen receptors was found in many tissues and organs. Recently, attention was paid to the fact that the effect of estrogens action on tissues and organs may depend not only on distribution, but also on their polymorphic types. The article presents the latest approach to the problem of metabolic consequences resulting from menopause, according to the possessed α estrogen receptor polymorphism (ERα).Genes encoding for ERα have many polymorphic variants, the most important of which from the clinical aspect are two single nucleotide polymorphisms (SNPs) - Xba1 and PvuII. The review of literature indicates that ERα polymorphisms are of great importance with respect to the effect of estrogens on the functioning of the body of a woman after menopause, and may imply the development of many pathological states, including the prevention or development of metabolic disorders. Identifying ERα polymorphisms may be useful in case of estrogen therapy for menopausal women who may benefit from it.
Topics: Estrogen Receptor alpha; Female; Humans; Menopause; Polymorphism, Genetic
PubMed: 27828688
DOI: 10.5603/EP.a2016.0058 -
Central-European Journal of Immunology 2014Neutrophil extracellular traps (NETs) are developed by nature to protect the body from furious invaders. On the other hand NET s can play an important role in human... (Review)
Review
Neutrophil extracellular traps (NETs) are developed by nature to protect the body from furious invaders. On the other hand NET s can play an important role in human pathology. Recent studies have shown that neutrophils are able to perform beneficial suicide to create an unique microbicidal net composed from cellular content attached to chromatic frame. It is a powerful tool that primary serve as protector from severe infections, but this weapon is also a double ended sword of the immunity. If overproduced NET s provoke certain autoimmune diseases, coagulation disorders and even cancer metastases. Moreover, due to the competition between host and pathogens, the microorganism have developed a width repertoire of sophisticated evading mechanisms, like creation of polysaccharide capsule or changes in cell wall charge. Therefore it is important to increase the knowledge about paths underlying NET s formation and degradation processes if we want to efficiently fight with bacterial infections and certain diseases.
PubMed: 26155111
DOI: 10.5114/ceji.2014.42136