Biomechanical Effects of Seizures on Cerebral Dynamics and Brain Stress.

Epilepsy is one of the most common neurological disorders globally, affecting about 50 million people, with nearly 80% of those affected residing in low- and middle-income countries. It is characterized by recurrent seizures that result from abnormal electrical brain activity, with seizures varying widely in manifestation. The exploration of the biomechanical effects that seizures have on brain dynamics and stress levels is relevant for the development of more effective treatments and protective strategies. This study uses a blend of experimental data and computational simulations to assess the brain's physical response during seizures, particularly focusing on the behavior of cerebrospinal fluid and the resulting mechanical stresses on different brain regions. Notable findings show increases in stress, predominantly in the posterior gyri and brainstem, during seizures and an evidence of brain displacement relative to the skull. These observations suggest a dynamic and complex interaction between the brain and skull, with maximum shear stress regions demonstrating the limited yet essential protective role of the CSF. By providing a deeper understanding of the mechanical changes occurring during seizures, this research supports the goal of advancing diagnostic tools, informing more targeted treatment interventions, and guiding the creation of customized therapeutic strategies to enhance neurological care and protect against the adverse effects of seizures.

Fluid-structure interaction analysis of amniotic fluid with fetus and placenta inside uterus exposed to military blasts.

INTRODUCTION: Pregnancy-related trauma is one of the leading causes of morbidity and mortality in pregnant women and fetuses. The fetal response to injury is largely dependent on the timing of fetal presentation and the underlying pathophysiology of the trauma. The optimal management of pregnant patients who have suffered an obstetric emergency depends on clinical assessment and understanding of the placental implantation process, which can be difficult to perform during an emergency. Understanding the mechanisms of traumatic injuries to the fetus is crucial for developing next-generation protective devices. METHODS: This study aimed to investigate the effect of amniotic fluid on mine blast on the uterus, fetus, and placenta via computational analysis. Finite element models were developed to analyze the effects of explosion forces on the uterus, fetus, and placenta, based on cadaveric data obtained from the literature. This study uses computational fluid-structure interaction simulations to study the effect of external loading on the fetus submerged in amniotic fluid inside of the uterus. RESULTS: Computational fluid-structure interaction simulations are used to study the effect of external loading on the fetus/placenta submerged in amniotic fluid inside the uterus. Cushioning function of the amniotic fluid on the fetus and placenta is demonstrated. The mechanism of traumatic injuries to the fetus/placenta is shown. DISCUSSION: The intention of this research is to understand the cushioning function of the amniotic fluid on the fetus. Further, it is important to make use of this knowledge in order to ensure the safety of pregnant women and their fetuses.

Prehospital transport and termination of resuscitation of cardiac arrest patients: A review of prehospital care protocols in the United States.

Background: The objective was to describe emergency medical services (EMS) protocol variability in transport expectations for out-of-hospital cardiac arrest (OHCA) patients and the involvement of online medical control for on-scene termination of resuscitation in the United States. Whether other aspects of OHCA care were mentioned, including the definition of a "pediatric" patient, and use of end-tidal carbon dioxide monitoring, mechanical chest compression devices (MCCDs), and extracorporeal membrane oxygenation (ECMO), were also described. Methods and Results: Review of EMS protocols publicly accessible from https://www.emsprotocols.org and through searches on the internet when protocols were unavailable on the website from June 2021 to January 2022. Frequencies and proportions were used to describe outcomes. Of 104 protocols reviewed, 51.9% state to initiate transport after return of spontaneous circulation (ROSC), 26.0% do not specify when to initiate transport, and 6.7% state to transport after ≥20 minutes of on-scene cardiopulmonary resuscitation for adults. For pediatric patients, 38.5% of protocols do not specify when to initiate transport, 32.7% state to transport after ROSC, and 10.6% state to transport as soon as possible. Most protocols (42.3%) did not specify the age that defines "pediatric" in cardiac arrest. More than half (51.9%) of the protocols require online medical control for termination of resuscitation. Most protocols mention the use of end-tidal carbon dioxide monitoring (81.7%), 50.0% mention the use of MCCDs, and 4.8% mention ECMO for cardiac arrest. Conclusions: In the United States, EMS protocols for initiation of transport and termination of resuscitation for OHCA patients are highly variable.

Effect of leukocyte-platelet-rich fibrin in bone healing around dental implants placed in conventional and wide osteotomy sites: A pre-clinical study.

Leukocyte-platelet-rich fibrin (L-PRF) has been suggested for gap management for immediate implant placement when the distance is greater than 2 mm. However, there remains a paucity in hierarchically designed research to support this application. The present study aimed to evaluate the effect of L-PRF on the osseointegration parameters of dental implants placed after conventional osteotomy of surgically created bone defects that simulate post extraction sockets in a canine model after 3, 6, and 12 weeks in vivo. Eighty dental implants (Intra-Lock, Boca Raton, FL) were placed in the radius of 13 beagle dogs. The experiment consisted of 4 groups (n = 20 implants/group): 1) Regular osteotomy (Reg n/L-PRF); 2) Regular osteotomy and implant placement with L-PRF membrane (Reg L-PRF); 3) Wide osteotomy with no gap management performed, where an osteotomy/bony defect (6 mm of diameter and ~5 mm deep) was created to simulate immediate implant placement in post-extraction sockets, and the gap was left for spontaneous healing (Wide nL-PRF); and 4) Wide osteotomy with L-PRF gap management (Wide L-PRF). L-PRF membranes were obtained by blood drawn from each subject and centrifuged at 2700 rpm (408 RCF-clot) for 12 min. In the experimental groups where L-PRF was utilized, the membrane was inserted into the osteotomy site prior to implant placement. Six dogs had implants placed in the radius for 3 weeks; and 7 dogs had implants placed in the left radius for 6 weeks and in the right radius for 12 weeks. At the corresponding experimental time points, samples were harvested, and subjected to histological processing for qualitative and quantitative analyses, via bone-to-implant contact (BIC) and bone-area-fraction occupancy (BAFO). Qualitative analysis demonstrated increased amounts of bone formation around the implant and within the healing chambers over time for all groups. While comparable histological features were observed for both Reg groups (L-PRF and nL-PRF), the gap management performed in Wide L-PRF group resulted in effective gap filling with improved bone growth in close proximity to the implant surface. Quantitative analyses of BIC and BAFO yielded higher values for both variables at 3 weeks for Wide L-PRF (~38% and ~56% respectively) compared to Wide nL-PRF (~20% for BIC and BAFO) (p < .03). No statistical differences were detected between Wide groups at 6 and 12 weeks, neither between Reg groups, independent of the association with or without the L-PRF membrane at all healing times. L-PRF placed within wide osteotomies, prior to implant placement, resulted in increased early bone formation compared to unfilled wide osteotomies at the early healing time (3 weeks in vivo).

Fluid-Structure Interaction Analyses of Biological Systems Using Smoothed-Particle Hydrodynamics.

Due to the inherent complexity of biological applications that more often than not include fluids and structures interacting together, the development of computational fluid-structure interaction models is necessary to achieve a quantitative understanding of their structure and function in both health and disease. The functions of biological structures usually include their interactions with the surrounding fluids. Hence, we contend that the use of fluid-structure interaction models in computational studies of biological systems is practical, if not necessary. The ultimate goal is to develop computational models to predict human biological processes. These models are meant to guide us through the multitude of possible diseases affecting our organs and lead to more effective methods for disease diagnosis, risk stratification, and therapy. This review paper summarizes computational models that use smoothed-particle hydrodynamics to simulate the fluid-structure interactions in complex biological systems.

Clinical, histological, and nanomechanical parameters of implants placed in healthy and metabolically compromised patients.

OBJECTIVES: To evaluate the clinical outcomes, histological parameters, and bone nanomechanical properties around implants retrieved from healthy and metabolic syndrome (MS) patients. METHODS: Twenty-four patients with edentulous mandibles (12/condition), received four implants between the mental foramina. An additional implant prototype was placed for retrieval histology. The following clinical outcomes were evaluated: insertion torque (IT), implant stability quotient (ISQ) values at baseline and after 60 days of healing, and implant survival. The prototype was retrieved after the healing and histologically processed for bone morphometric evaluation of bone-to-implant contact (%BIC) and bone area fraction occupancy (%BAFO), and bone nanoindentation to determine the elastic modulus (Em) and hardness (H). Descriptive statistical procedures and survival tests were used to analyze the data. RESULTS: The final study population was comprised of 10 women and 11 men (∼64 years). A total of 105 implants were placed, 21 retrieved for histology. Implant survival rates were similar between groups (>99 %). Similarly, IT and ISQ analyses showed no significant association with systemic condition (p > 0.216). Histological micrographs depicted similar bone morphology, woven bone, for both conditions. While MS (33 ±â€¯5.3 %) and healthy (39 ±â€¯6.5 %) individuals showed no significant difference for %BIC (p = 0.116), significantly higher %BAFO was observed for healthy (45 ±â€¯4.6 %) relative to MS (30 ±â€¯3.8 %) (p < 0.001). No significant differences on bone nanomechanical properties was observed (p > 0.804). CONCLUSIONS: Although no significant influence on clinical parameters and bone nanomechanical properties was observed, MS significantly reduced bone formation in the peri-implant area in the short-term. CLINICAL SIGNIFICANCE: A lower amount of bone formation in the peri-implant area was observed in comparison to healthy patients, although the other short-term clinical outcomes were not significantly different. Considering the escalating prevalence of MS patients in need for implant treatment, it becomes crucial to understand bone-to-implant response to determine the ideal loading time in this population.

Bone regeneration at extraction sockets filled with leukocyte-platelet-richfibrin: An experimental pre-clinical study

Background: We aimed to histomorphometrically evaluate the effects of Leucocyte-Platelet-Rich Fibrin (L-PRF),with and without the combination of a bone grafting material, for alveolar ridge preservation using an in vivocanine model.Material and Methods: Seven dogs (Female Beagles, ~18-month-old) were acquired for the study. L-PRF wasprepared from each individual animal by drawing venous blood and spinning them through a centrifuge at 408RCF-clot (IntrasSpin, Intra-Lock, Boca Raton, FL). L-PRF membranes were obtained from XPression fabrication kit (Biohorizons Implant Systems, Inc., AL, USA). A split mouth approach was adopted with the first molarmesial and distal socket defects treated in an interpolated fashion of the following study groups: 1) Empty socket (negative control); 2) OSS filled defect 3) L-PRF membrane; and 4) Mix of Bio-Oss® with L-PRF. After six weeks,samples were harvested, histologically processed, and evaluated for bone area fraction occupancy (BAFO), vertical/horizontal ridge dimensions (VRD and HRD, respectively), and area of coronal soft tissue infiltration.Results: BAFO was statistically lower for the control group in comparison to all treatment groups. Defects treatedwith Bio-Oss® were not statistically different then defects treated solely with L-PRF. Collapsed across all groups,L-PRF exhibited higher degrees of BAFO than groups without L-PRF. Defects filled with Bio-Oss® and Bio-Oss®with L-PRF demonstrated greater maintenance of VRD relative to the control group. Collapsed across all groups,Bio-Oss® maintained the VRD and resulted in less area of coronal soft tissue infiltration compared to the emptydefect. Soft tissue infiltration observed at the coronal area was not statistically different among defects filled withL-PRF, Bio-Oss®, and Bio-Oss® with L-PRF.Conclusions: Inclusion of L-PRF to particulate xenograft did not promote additional bone heading at 6 weeks invivo. ... (AU)