Tap water quality: in the eye of the beholder.

The quality of tap water is important. We consider whether objective measures of water quality factor into satisfaction with tap water among a large sample of Norwegian citizens. Our data include over 40,000 observations from the last decade and constitute an unprecedented empirical basis for investigating the link between water quality and user satisfaction. Objective measures of water quality include tests on Escherichia coli, intestinal enterococci, pH, and color. Only color has a significant impact on citizens' satisfaction with tap water. However, individual characteristics can to some degree predict tap water satisfaction. For example, the general level of satisfaction with public services and society, age, education, income, and gender are relevant characteristics. Our data are rich enough to allow for the use of fixed effects to control for unique municipal factors, such as geography and access to water sources, as well as time trends. Thus, we provide rather solid evidence that satisfaction with tap water is unrelated to several objective measures of quality, but that satisfaction is related to several individual characteristics.

Management of pediatric forearm fractures: what is the best therapeutic choice? A narrative review of the literature.

PURPOSE: This narrative review intends to summarize the most important and relevant data on diagnosis and treatment of pediatric forearm fractures and to describe the characteristics and advantage of each therapeutic option. METHODS: We conducted a literature research considering peer-reviewed papers (mainly clinical trials or scientific reviews) using the string "forearm fracture AND epidemiology" or "forearm fracture AND diagnosis or " forearm fracture AND treatment" or "forearm fracture AND casting" or "forearm fracture AND surgery". Studies were identified by searching electronic databases (MEDLINE and PubMed) till April 2020 and reference lists of retrieved articles. Only English-language articles were included in the review. RESULTS: Conservative management with cast immobilization is a safe and successful treatment option in pediatric forearm fractures. Surgical indication is recommended when an acceptable reduction cannot be obtained with closed reduction and casting. Surgical treatment options are intramedullary nail, plating and hybrid fixation. CONCLUSIONS: There is not a unique consensus about fracture management and treatment. Further studies are necessary to create univocal guidelines about optimal treatment, considering new techniques and available technologies.

A contraction approach to dynamic optimization problems.

An infinite-horizon, multidimensional optimization problem with arbitrary yet finite periodicity in discrete time is considered. The problem can be posed as a set of coupled equations. It is shown that the problem is a special case of a more general class of contraction problems that have unique solutions. Solutions are obtained by considering a vector-valued value function and by using an iterative process. Special cases of the general class of contraction problems include the classical Bellman problem and its stochastic formulations. Thus, our approach can be viewed as an extension of the Bellman problem to the special case of nonautonomy that periodicity represents, and our approach thereby facilitates consistent and rigorous treatment of, for example, seasonality in discrete, dynamic optimization, and furthermore, certain types of dynamic games. The contraction approach is illustrated in simple examples. In the main example, which is an infinite-horizon resource management problem with a periodic price, it is found that the optimal exploitation level differs between high and low price time intervals and that the solution time paths approach a limit cycle.

Matrix superhighways configurations: new concepts for complex organ regeneration.

New ideas and experimental models for tissue and organ regeneration are urgently needed. There are several exciting challenges in the field of organogenesis that need to be defined. The integrated signals and molecular repertoires that shape the particular architecture of specific organs like the kidney or the liver are not completely understood yet. To develop a new scientific platform to be able to build up complex organs we have established a research program using basically Acellular Xenogeneic Isomorphic Matrices (AXIMs) and mesenchymal stem cells (MSCs) generating the necessary concepts for the definition, production, and application of the specific configurations of these matrices for organ regeneration. New and interesting pathways for MSC differentiation were identified. We believe that all extracellular matrices were created fundamentally equal or at least very similar in nature. We also believe that there are true "matrix superhighway configurations" with different three-dimensional geometrical architectures as well as biochemical, electrical, and molecular properties that are tissue and organ specific that influence cell differentiation and organogenesis and will be fundamental for the in vitro regeneration of complex organs for transplantation.

A novel approach to the quantification of aortic root in vivo structural mechanics.

Understanding aortic root in vivo biomechanics can help in elucidating key mechanisms involved in aortic root pathologies and in the outcome of their surgical treatment. Numerical models can provide useful quantitative information. For this to be reliable, detailed aortic root anatomy should be captured. Also, since the aortic root is never unloaded throughout the cardiac cycle, the modeled geometry should be consistent with the in vivo loads acting on it. Achieving such consistency is still a challenge, which was tackled only by few numerical studies. Here we propose and describe in detail a new approach to the finite element modeling of aortic root in vivo structural mechanics. Our approach exploits the anatomical information yielded by magnetic resonance imaging by reconstructing the 3-dimensional end-diastolic geometry of the aortic root and makes the reconstructed geometry consistent with end-diastolic loading conditions through the estimation of the corresponding prestresses field. We implemented our approach through a semiautomated modeling pipeline, and we applied it to quantify aortic root biomechanics in 4 healthy participants. Computed results highlighted that including prestresses into the model allowed for pressurizing the aortic root to the end-diastolic pressure while matching the image-based ground truth data. Aortic root dynamics, tissues strains, and stresses computed at relevant time points through the cardiac cycle were consistent with a broad set of data from previous computational and in vivo studies, strongly suggesting the potential of the method. Also, results highlighted the major role played by the anatomy in driving aortic root biomechanics.

Towards the improved quantification of in vivo abnormal wall shear stresses in BAV-affected patients from 4D-flow imaging: Benchmarking and application to real data.

Bicuspid aortic valve (BAV), i.e. the fusion of two aortic valve cusps, is the most frequent congenital cardiac malformation. Its progression is often characterized by accelerated leaflet calcification and aortic wall dilation. These processes are likely enhanced by altered biomechanical stimuli, including fluid-dynamic wall shear stresses (WSS) acting on both the aortic wall and the aortic valve. Several studies have proposed the exploitation of 4D-flow magnetic resonance imaging sequences to characterize abnormal in vivo WSS in BAV-affected patients, to support prognosis and timing of intervention. However, current methods fail to quantify WSS peak values. On this basis, we developed two new methods for the improved quantification of in vivo WSS acting on the aortic wall based on 4D-flow data. We tested both methods separately and in combination on synthetic datasets obtained by two computational fluid-dynamics (CFD) models of the aorta with healthy and bicuspid aortic valve. Tests highlighted the need for data spatial resolution at least comparable to current clinical guidelines, the low sensitivity of the methods to data noise, and their capability, when used jointly, to compute more realistic peak WSS values as compared to state-of-the-art methods. The integrated application of the two methods on the real 4D-flow data from a preliminary cohort of three healthy volunteers and three BAV-affected patients confirmed these indications. In particular, quantified WSS peak values were one order of magnitude higher than those reported in previous 4D-flow studies, and much closer to those computed by highly time- and space-resolved CFD simulations.

Mass-spring models for the simulation of mitral valve function: Looking for a trade-off between reliability and time-efficiency.

Patient-specific finite element (FE) models can assess the impact of mitral valve (MV) repair on the complex MV anatomy and function. However, FE excessive time requirements hamper their use for surgical planning; mass-spring models (MSMs) represent a more approximate approach but can provide almost real-time simulations. On this basis, we implemented MSMs of three healthy MVs from cardiac magnetic resonance (cMR) imaging to simulate the systolic MV closure, including the in vivo papillary muscles and annular kinematics, and the anisotropic and non-linear mechanical response of MV tissues. To test MSM reliability we compared the systolic peak configurations computed by MSMs and FE: mismatches by less than twice the in-plane cMR image resolution were detected over 75% of the leaflets' surface, independently of the MSM mesh refinement and of the specific MV anatomy. Data on MSMs time-efficiency and data from the comparison of MSMs vs. FE models suggest that MSM could represent a suitable trade-off between almost real-time simulations and reliability when computing MV systolic configuration, with the potential to be used in a clinical setting either as a support to the decisional process or as a virtual training tool.

Bloodstream cells phenotypically identical to human mesenchymal bone marrow stem cells circulate in large amounts under the influence of acute large skin damage: new evidence for their use in regenerative medicine.

OBJECTIVES: Recent work has shown that human bone marrow contains mesenchymal stem cells (MSCs). However, little is known about their presence in peripheral blood. Since these cells are potentially responsible for tissue repair after injury, their number should be increased during these situations. To demonstrate their number during these situations, we measured MSCs in the peripheral blood of healthy donors and burn patients. MATERIALS AND METHODS: Blood samples were obtained from 15 acute burn patients and 15 healthy donors. We performed flow cytometric analysis, using a large monoclonal antibody panel: CD44, CD45, CD14, DR, CD34, CD19, CD13, CD29, CD105, CD1a, CD90, CD38, CD25. MSC phenotype was considered positive for CD44, CD13, CD29, CD90, and CD105, and negative for the other monoclonals. The testing was performed on day 3 after injury. We correlated the results with the age, sex, and size and type of burns. RESULTS: Cells expressing the MSC phenotype were detected in the peripheral blood of both groups. Noteworthy, compared with samples from healthy donors (0.0078 +/- 0.0044), blood obtained from burn patients showed a higher MSC percentage (0.1643 +/- 0.115; P < .001). The percentage of MSCs correlated with the size and severity of the burn. Increased values were also observed among younger patients. CONCLUSIONS: MSCs have an important role in regenerative processes of human tissues. We found cells phenotypically identical to MSCs circulating in physiological number in normal subjects, but in significantly higher amounts during acute large burns. Therefore, they may represent a previously unrecognized circulatory component to the process of skin regeneration.

Human mesenchymal stem cells are tolerized by mice and improve skin and spinal cord injuries.

INTRODUCTION: We sought to use human mesenchymal stem cells (HMSC) for skin and spinal cord repair in mice. MATERIALS AND METHODS: Human bone marrow obtained from a young healthy donor was used to separate and culture human mesenchymal stem cells (HMSC). Ten mice were included in each of four groups. A full-thickness skin defect was surgically performed on all mice in groups 1 and 2. A transverse complete medullar section was performed in groups 3 and 4. Groups 1 and 3 received HMSC IV infusion and local HMSC polymer implant. Groups 2 and 4 received only the IV HMSC infusion. Five control animals from each group went through the same lesions but they didn't receive treatment. RESULTS: After local administration of HMSC into the fibrin polymer combined with the IV infusion of HMSC, there was no immune rejection; all skin defects healed without scar or retraction at a median time of 14 days. Sixty percent of the animals treated with IV infusion and polymer with HMSC simultaneously had improved neurological activities, while all control mice with spinal cord injury experiments died or perpetuated their paralysis with worsening muscular atrophy and increasing propensity to skin damage. CONCLUSIONS: HMSC are not immunologically reactive and can trespass species defense barriers. Animals treated with these cells repaired injuries better than controls. In this way we propose that universal HMSC from donors can be cultured, expanded, and cryopreserved to be used in human organ or tissue regeneration.

Anatomical and mechanical considerations of craniofacial fractures: an experimental study.

By inflicting blows to cadavers, a study was made of injuries to the craniofacial bone lattice. On the basis of these experimental results, a classification of craniofacial fractures is offered.

The next generation of burns treatment: intelligent films and matrix, controlled enzymatic debridement, and adult stem cells.

We describe a novel technology based on nanoengineered multifunctional acellular biologic scaffolds combined with wound dressings and films of the same kind. This method allows selective delivery and release of shielded biomaterials and bioactive substances to a desired wound or damaged tissue while stimulating the selective anchoring and adhesion of endogenous circulating repairing cells, such as mesenchymal stem cells, to obtain a faster and more physiologic healing process. We also present a new controlled enzymatic debridement process for more effective burned tissue scarolysis. In light of our preliminary in vitro and in vivo data, we are convinced that these approaches can include the use of other kinds of adult stem cells, such as endometrial regenerative cells, to improve the vascularization of the constructs, with great potential in the entire tissue and organ regeneration field but especially for the treatment of severely burned patients, changing the way these lesions may be treated in the future.

Outstanding survival and regeneration process by the use of intelligent acellular dermal matrices and mesenchymal stem cells in a burn pig model.

A pig model with a deep large burn was used to study the regeneration process induced by mesenchymal stem cells (MSCs) and acellular pig dermal matrices, made intelligent by the combination with biodegradable nanofibers loaded with growth factors (granulocyte-macrophage colony-stimulating factor and epidermal growth factor) and coated with the anti-CD44 monoclonal antibody (intelligent acellular dermal matrices, IADMs). These IADMs are specially designed to integrate in the wound bed as new biological scaffolds as well as to specifically recruit and attach circulating and/or externally applied MSCs through the anti-CD44 antibody while delivering precise amounts of growth factors. In this way, the reparative process as well as the aesthetic and functional results were enhanced in our burn model. The animal survived, the wound was completely closed, and total regeneration of the skin was obtained without much scarring. Surprisingly, hair follicles and other skin appendages developed despite the severity and deepness of the burn. Even burned muscles and ribs seemed to have undergone a regenerative process by the end of the study. Based on these findings, we have proposed the use of IADMs and autologous, allogeneic or xenogeneic MSCs, as a new paradigm for the future treatment of large burns and probably other dermatological and cosmetic human conditions.

La curación de las heridas de gran superficie y la medicina regenerativa / Wound healing of large surface and regenerative medicine

La medicina regenerativa, con los conocimientos de la biología celular y molecular, llegó a las especialidades quirúrgicas y así a la atención del paciente. Se describen los fundamentos teóricos de un nuevo concepto de curación de las superficies cruentas. Se explica un nuevo procedimiento de curación de las heridas no infectadas a través del uso de un epitelio transitorio que al evitar la evaporación protege a las señales electromagnéticas de información entre célula y célula, así como la regeneración de un nuevo tejido mediante el uso de ADM. Se presentan cinco pacientes críticos, cuatro de ellos con indicación de amputación por la gravedad del traumatismo.

Regenerative medicine with knowledge of cell and molecular biology, reached the surgical specialities and thereby patient care. It describes the theoretical basis of a new concept of wound healing and a new procedure for healing of uninfected wounds through the use of a transitional epithelium to prevent evaporation that protects information of the electromagnetic signals between the cells, and regeneration of a new tissue using ADM. We present five critical patients, four of them with an indication of amputation due to the severity of the injury.

La curación de las heridas de gran superficie y la medicina regenerativa / Wound healing of large surface and regenerative medicine

La medicina regenerativa, con los conocimientos de la biología celular y molecular, llegó a las especialidades quirúrgicas y así a la atención del paciente. Se describen los fundamentos teóricos de un nuevo concepto de curación de las superficies cruentas. Se explica un nuevo procedimiento de curación de las heridas no infectadas a través del uso de un epitelio transitorio que al evitar la evaporación protege a las señales electromagnéticas de información entre célula y célula, así como la regeneración de un nuevo tejido mediante el uso de ADM. Se presentan cinco pacientes críticos, cuatro de ellos con indicación de amputación por la gravedad del traumatismo. (AU)

Regenerative medicine with knowledge of cell and molecular biology, reached the surgical specialities and thereby patient care. It describes the theoretical basis of a new concept of wound healing and a new procedure for healing of uninfected wounds through the use of a transitional epithelium to prevent evaporation that protects information of the electromagnetic signals between the cells, and regeneration of a new tissue using ADM. We present five critical patients, four of them with an indication of amputation due to the severity of the injury. (AU)