Spatial Anisotropies and Temporal Fluctuations in Extracellular Matrix Network Texture during Early Embryogenesis

Early stages of vertebrate embryogenesis are characterized by a remarkable series of shape changes. The resulting morphological complexity is driven by molecular, cellular, and tissue-scale biophysical alterations. Operating at the cellular level, extracellular matrix (ECM) networks facilitate cell motility. At the tissue level, ECM networks provide material properties required to accommodate the large-scale deformations and forces that shape amniote embryos. In other words, the primordial biomaterial from which reptilian, avian, and mammalian embryos are molded is a dynamic composite comprised of cells and ECM. Despite its central importance during early morphogenesis we know little about the intrinsic micrometer-scale surface properties of primordial ECM networks. Here we computed, using avian embryos, five textural properties of fluorescently tagged ECM networks — (a) inertia, (b) correlation, (c) uniformity, (d) homogeneity, and (e) entropy. We analyzed fibronectin and fibrillin-2 as examples of fibrous ECM constituents. Our quantitative data demonstrated differences in the surface texture between the fibronectin and fibrillin-2 network in Day 1 (gastrulating) embryos, with the fibronectin network being relatively coarse compared to the fibrillin-2 network. Stage-specific regional anisotropy in fibronectin texture was also discovered. Relatively smooth fibronectin texture was exhibited in medial regions adjoining the primitive streak (PS) compared with the fibronectin network investing the lateral plate mesoderm (LPM), at embryonic stage 5. However, the texture differences had changed by embryonic stage 6, with the LPM fibronectin network exhibiting a relatively smooth texture compared with the medial PS-oriented network. Our data identify, and partially characterize, stage-specific regional anisotropy of fibronectin texture within tissues of a warm-blooded embryo. The data suggest that changes in ECM textural properties reflect orderly time-dependent rearrangements of a primordial biomaterial. We conclude that the ECM microenvironment changes markedly in time and space during the most important period of amniote morphogenesis—as determined by fluctuating textural properties

A 'snip' in time: what is the best age to circumcise?

<p>Abstract</p> <p>Background</p> <p>Circumcision is a common procedure, but regional and societal attitudes differ on whether there is a need for a male to be circumcised and, if so, at what age. This is an important issue for many parents, but also pediatricians, other doctors, policy makers, public health authorities, medical bodies, and males themselves.</p> <p>Discussion</p> <p>We show here that infancy is an optimal time for clinical circumcision because an infant's low mobility facilitates the use of local anesthesia, sutures are not required, healing is quick, cosmetic outcome is usually excellent, costs are minimal, and complications are uncommon. The benefits of infant circumcision include prevention of urinary tract infections (a cause of renal scarring), reduction in risk of inflammatory foreskin conditions such as balanoposthitis, foreskin injuries, phimosis and paraphimosis. When the boy later becomes sexually active he has substantial protection against risk of HIV and other viral sexually transmitted infections such as genital herpes and oncogenic human papillomavirus, as well as penile cancer. The risk of cervical cancer in his female partner(s) is also reduced. Circumcision in adolescence or adulthood may evoke a fear of pain, penile damage or reduced sexual pleasure, even though unfounded. Time off work or school will be needed, cost is much greater, as are risks of complications, healing is slower, and stitches or tissue glue must be used.</p> <p>Summary</p> <p>Infant circumcision is safe, simple, convenient and cost-effective. The available evidence strongly supports infancy as the optimal time for circumcision.</p

Cost of Hospitalization for Preterm and Low Birth Weight Infants in the United States

ABSTRACT OBJECTIVE. The objective of this study was to estimate national hospital costs for infant admissions that are associated with preterm birth/low birth weight. METHODS. Infant (Ͻ1 year) hospital discharge data, including delivery, transfers, and readmissions, were analyzed by using the 2001 Nationwide Inpatient Sample from the Healthcare Cost and Utilization Project. The Nationwide Inpatient Sample is a 20% sample of US hospitals weighted to approximately Ͼ35 million hospital discharges nationwide. Hospital costs, based on weighted cost-to-charge ratios, and lengths of stay were calculated for preterm/low birth weight infants, uncomplicated newborns, and all other infant hospitalizations and assessed by degree of prematurity, major complications, and expected payer. RESULTS. In 2001, 8% (384 200) of all 4.6 million infant stays nationwide included a diagnosis of preterm birth/low birth weight. Costs for these preterm/low birth weight admissions totaled $5.8 billion, representing 47$15 100, with a mean length of stay of 12.9 days versus 600 and 1.9 days for uncomplicated newborns. Costs were highest for extremely preterm infants (Ͻ28 weeks' gestation/birth weight Ͻ1000 g), averaging 65 600, and for specific respiratory-related complications. However, two thirds of total hospitalization costs for preterm birth/low birth weight were for the substantial number of infants who were not extremely preterm. Of all preterm/low birth weight infant stays, 50% identified private/commercial insurance as the expected payer, and 42% designated Medicaid. CONCLUSIONS. Costs per infant hospitalization were highest for extremely preterm infants, although the larger number of moderately preterm/low birth weight infants contributed more to the overall costs. Preterm/low birth weight infants in the United States account for half of infant hospitalization costs and one quarter of pediatric costs, suggesting that major infant and pediatric cost savings could be realized by preventing preterm birth. www.pediatrics.org/cg

Towards an Embodied Developing Vision System

Many cognitive scientists now agree that artificial cognition might be probably achieved developmentally, starting from a set of basic-level premature capabilities and incrementally self-extending itself with experience through discrete or continuous stages bred with experience. Although we are still far from seeing an artificial full-fledged self-extending cognitive system, the literature has provided promising examples and demonstrations. Nonetheless, not much thought is given to the modeling of how an artificial vision system, an important part of a developing cognitive system, can develop itself in a similar manner. In this article, we dwell upon the issue of a developing vision system, the relevant problems and possible solutions whenever possible