Mass vaccination with reassortment-impaired live H9N2 avian influenza vaccine.

Avian influenza poses a severe threat to poultry production and global food security, prompting the development of vaccination programs in numerous countries. Modified live virus (MLV) vaccines, with their potential for mass application, offer a distinct advantage over existing options. However, concerns surrounding reversion, recombination, and unintended transmission have hindered the progress of MLV development for avian influenza in poultry. To address these concerns, we engineered reassortment-impaired, non-transmissible, safe, immunogenic, and protective MLVs through the rearrangement of internal gene segments and additional modifications to the surface gene segments HA and NA. The unique peptide marker aspartic acid-arginine-proline-alanine-valine-isoleucine-alanine-asparragine (DRPAVIAN) was incorporated into HA, while NA was modified to encode the chicken interleukin-18 (ckIL18) gene (MLV-H9N2-IL). In vitro, the MLV-H9N2 and MLV-H9N2-IL candidates demonstrated stability and virus titers comparable to the wild-type H9N2 strain. In chickens, the MLV-H9N2 and MLV-H9N2-IL candidates did not transmit via direct contact. Co-infection studies with wild-type virus confirmed that the altered HA and NA segments exhibited fitness disadvantages and did not reassort. Vaccinated chickens showed no clinical signs upon vaccination, all seroconverted, and the inclusion of ckIL18 in the MLV-H9N2-IL vaccine enhanced neutralizing antibody production. A significant decrease in viral loads post-challenge underscored the protective effect of the MLVs. The MLV-H9N2-IL vaccine, administered via drinking water, proved immunogenic in chickens in a dose-dependent manner, generating protective levels of neutralizing antibodies upon aggressive homologous virus challenge. In summary, this study lays the groundwork for safe MLVs against avian influenza suitable for mass vaccination efforts.

Preclinical efficacy profiles of the sigma-1 modulator E1R and of fenfluramine in two chronic mouse epilepsy models.

OBJECTIVE: Given its key homeostatic role affecting mitochondria, ionotropic and metabotropic receptors, and voltage-gated ion channels, sigma-1 receptor (Sig1R) represents an interesting target for epilepsy management. Antiseizure effects of the positive allosteric modulator E1R have already been reported in acute seizure models. Although modulation of serotonergic neurotransmission is considered the main mechanism of action of fenfluramine, its interaction with Sig1R may be of additional relevance. METHODS: To further explore the potential of Sig1R as a target, we assessed the efficacy and tolerability of E1R and fenfluramine in two chronic mouse models, including an amygdala kindling paradigm and the intrahippocampal kainate model. The relative contribution of the interaction with Sig1R was analyzed using combination experiments with the Sig1R antagonist NE-100. RESULTS: Whereas E1R exerted pronounced dose-dependent antiseizure effects at well-tolerated doses in fully kindled mice, only limited effects were observed in response to fenfluramine, without a clear dose dependency. In the intrahippocampal kainate model, E1R failed to influence electrographic seizure activity. In contrast, fenfluramine significantly reduced the frequency of electrographic seizure events and their cumulative duration. Pretreatment with NE-100 reduced the effects of E1R and fenfluramine in the kindling model. Surprisingly, pre-exposure to NE-100 in the intrahippocampal kainate model rather enhanced and prolonged fenfluramine's antiseizure effects. SIGNIFICANCE: In conclusion, the kindling data further support Sig1R as an interesting target for novel antiseizure medications. However, it is necessary to further explore the preclinical profile of E1R in chronic epilepsy models with spontaneous seizures. Despite the rather limited effects in the kindling paradigm, the findings from the intrahippocampal kainate model suggest that it is of interest to further assess a possible broad-spectrum potential of fenfluramine.

Intracellular Streptococcus pneumoniae develops enhanced fluoroquinolone persistence during influenza A coinfection.

Streptococcus pneumoniae is a major pathogen responsible for severe complications in patients with prior influenza A virus (IAV) infection. We have previously demonstrated that S. pneumoniae exhibits increased intracellular survival within IAV-infected cells. Fluoroquinolones (FQs) are widely used to treat pneumococcal infections. However, our prior work has shown that S. pneumoniae can develop intracellular FQ persistence, a phenomenon triggered by oxidative stress within host cells. This persistence allows the bacteria to withstand high FQ concentrations. In this study, we show that IAV infection enhances pneumococcal FQ persistence during intracellular survival within pneumocytes, macrophages, and neutrophils. This enhancement is partly due to increased oxidative stress induced by the viral infection. We find that this phenotype is particularly pronounced in autophagy-proficient host cells, potentially resulting from IAV-induced blockage of autophagosome-lysosome fusion. Moreover, we identified several S. pneumoniae genes involved in oxidative stress response that contribute to FQ persistence, including sodA (superoxide dismutase), clpL (chaperone), nrdH (glutaredoxin), and psaB (Mn+2 transporter component). Our findings reveal a novel mechanism of antibiotic persistence promoted by viral infection within host cells. This underscores the importance of considering this phenomenon when using FQs to treat pneumococcal infections, especially in patients with concurrent influenza A infection.

Classification of anticancer drugs: an update with FDA- and EMA-approved drugs.

Anticancer systemic therapy comprises a complex and growing group of drugs. Some of the new agents with novel mechanisms of action that have appeared are difficult to fit in the groups of classical chemotherapy, hormones, tyrosine-kinase inhibitors, and monoclonal antibodies. We propose a classification based on two levels of information: the site of action and the mechanism of action. Regarding the former, drugs can exert their action in the tumor cell, the tumor vasculature, the immune system, or the endocrine system. The mechanism of action refers to the molecular target.

Anti-hemagglutinin monomeric nanobody provides prophylactic immunity against H1 subtype influenza A viruses.

Influenza viruses constitute a major threat to human health globally. The viral surface glycoprotein hemagglutinin (HA) is the immunodominant antigen, contains the site for binding to the cellular receptor (RBS), and it is the major target of neutralizing antibody responses post-infection. We developed llama-derived single chain antibody fragments (VHHs) specific for type A influenza virus. Four VHHs were identified and further characterized. VHH D81 bound residues in the proximity of the C-terminal region of HA1 of H1 and H5 subtypes, and showed weak neutralizing activity, whereas VHH B33 bound residues in the proximity of the N-terminal region of the HA's stem domain (HA2) of H1, H5, and H9 subtypes, and showed no neutralizing activity. Of most relevance, VHHs E13 and G41 recognized highly conserved conformational epitopes on the H1 HA's globular domain (HA1) and showed high virus neutralizing activity (ranging between 0.94 to 0.01µM), when tested against several human H1N1 isolates. Additionally, E13 displayed abrogated virus replication of a panel of H1N1 strains spanning over 80 years of antigenic drift and isolated from human, avian, and swine origin. Interestingly, E13 conferred protection in vivo at a dose as low as 0.05 mg/kg. Mice treated with E13 intranasally resulted in undetectable virus challenge loads in the lungs at day 4 post-challenge. The transfer of sterilizing pan-H1 immunity, by a dose in the range of micrograms given intranasally, is of major significance for a monomeric VHH and supports the further development of E13 as an immunotherapeutic agent for the mitigation of influenza infections.

WNT Oncogenic Transcription Requires MYC Suppression of Lysosomal Activity and EPCAM Stabilization in Gastric Tumors.

BACKGROUND & AIMS: WNT signaling is central to spatial tissue arrangement and regulating stem cell activity, and it represents the hallmark of gastrointestinal cancers. Although its role in driving intestinal tumors is well characterized, WNT's role in gastric tumorigenesis remains elusive. METHODS: We have developed mouse models to control the specific expression of an oncogenic form of ß-catenin (CTNNB1) in combination with MYC activation in Lgr5+ cells of the gastric antrum. We used multiomics approaches applied in vivo and in organoid models to characterize their cooperation in driving gastric tumorigenesis. RESULTS: We report that constitutive ß-catenin stabilization in the stomach has negligible oncogenic effects and requires MYC activation to induce gastric tumor formation. Although physiologically low MYC levels in gastric glands limit ß-catenin transcriptional activity, increased MYC expression unleashes the WNT oncogenic transcriptional program, promoting ß-catenin enhancer invasion without a direct transcriptional cooperation. MYC activation induces a metabolic rewiring that suppresses lysosomal biogenesis through mTOR and ERK activation and MiT/TFE inhibition. This prevents EPCAM degradation by macropinocytosis, promoting ß-catenin chromatin accumulation and activation of WNT oncogenic transcription. CONCLUSION: Our results uncovered a new signaling framework with important implications for the control of gastric epithelial architecture and WNT-dependent oncogenic transformation.

Efficiently handling constraints in mixed-integer nonlinear programming problems using gradient-based repair differential evolution.

Mixed integer nonlinear programming (MINLP) addresses optimization problems that involve continuous and discrete/integer decision variables, as well as nonlinear functions. These problems often exhibit multiple discontinuous feasible parts due to the presence of integer variables. Discontinuous feasible parts can be analyzed as subproblems, some of which may be highly constrained. This significantly impacts the performance of evolutionary algorithms (EAs), whose operators are generally insensitive to constraints, leading to the generation of numerous infeasible solutions. In this article, a variant of the differential evolution algorithm (DE) with a gradient-based repair method for MINLP problems (G-DEmi) is proposed. The aim of the repair method is to fix promising infeasible solutions in different subproblems using the gradient information of the constraint set. Extensive experiments were conducted to evaluate the performance of G-DEmi on a set of MINLP benchmark problems and a real-world case. The results demonstrated that G-DEmi outperformed several state-of-the-art algorithms. Notably, G-DEmi did not require novel improvement strategies in the variation operators to promote diversity; instead, an effective exploration within each subproblem is under consideration. Furthermore, the gradient-based repair method was successfully extended to other DE variants, emphasizing its capacity in a more general context.

A review of the WHO strategy on traditional, complementary, and integrative medicine from the perspective of academic consortia for integrative medicine and health.

Despite important progress in modern medicine, widely regarded as an indispensable foundation of healthcare in all highly advanced nations and regions, not all patients respond well to available treatments in biomedicine alone. Additionally, there are concerns about side effects of many medications and interventions, the unsustainable cost of healthcare and the low resolution of chronic non-communicable diseases and mental disorders whose incidence has risen in the last decades. Besides, the chronic stress and burnout of many healthcare professionals impairs the therapeutic relationship. These circumstances call for a change in the current paradigm and practices of biomedicine healthcare. Most of the world population (80%) uses some form of traditional, complementary, and integrative medicine (T&CM), usually alongside biomedicine. Patients seem equally satisfied with biomedicine and T&CM, but in the field of T&CM there are also many challenges, such as unsupported claims for safety and/or efficacy, contamination of herbal medicines and problems with regulation and quality standards. As biomedicine and T&CM seem to have different strengths and weaknesses, integration of both approaches may be beneficial. Indeed, WHO has repeatedly called upon member states to work on the integration of T&CM into healthcare systems. Integrative medicine (IM) is an approach that offers a paradigm for doing so. It combines the best of both worlds (biomedicine and T&CM), based on evidence for efficacy and safety, adopting a holistic personalized approach, focused on health. In the last decades academic health centers are increasingly supportive of IM, as evidenced by the foundation of national academic consortia for integrative medicine in Brazil (2017), the Netherlands (2018), and Germany (2024) besides the pioneering American consortium (1998). However, the integration process is slow and sometimes met with criticism and even hostility. The WHO T&CM strategies (2002-2005 and 2014-2023) have provided incipient guidance on the integration process, but several challenges are yet to be addressed. This policy review proposes several possible solutions, including the establishment of a global matrix of academic consortia for IM, to update and extend the WHO T&CM strategy, that is currently under review.

Diazoxon exposure increases susceptibility to infection by Salmonella Typhimurium.

Various exogenous factors, such as microbiological and chemical contamination condition food security. Salmonella Typhimurium (S. Typhimurium) is the cause of salmonellosis. This bacterium utilizes phagocytosis to create bacterial reservoirs. On the other hand, exposure to chemical contaminants, such as pesticides, increases susceptibility to numerous infections. Therefore, this research aims to evaluate the effect of co-exposure to diazoxon and S. Typhimurium on the in vitro infection dynamics. For this purpose, human mononuclear cells were pre-exposed in vitro to diazoxon and then challenged with S. Typhimurium at 1, 8, and 24 h. Bacterial internalization, actin polymerization, and reactive oxygen species (ROS) were analyzed. Obtained data show that mononuclear cells previously exposed to diazoxon exhibit greater internalization of S. Typhimurium. Likewise, greater ROS production and an increase in actin polymerization were observed. Therefore, in the proposed scenario, obtained data suggest that co-exposure to diazoxon and S. Typhimurium increases susceptibility to acquiring an illness.

Rescue in vitro maturation using ovarian support cells of human oocytes from conventional stimulation cycles yields oocytes with improved nuclear maturation and transcriptomic resemblance to in vivo matured oocytes.

PURPOSE: Determine if the gene expression profiles of ovarian support cells (OSCs) and cumulus-free oocytes are bidirectionally influenced by co-culture during in vitro maturation (IVM). METHODS: Fertility patients aged 25 to 45 years old undergoing conventional ovarian stimulation donated denuded immature oocytes for research. Oocytes were randomly allocated to either OSC-IVM culture (intervention) or Media-IVM culture (control) for 24-28 h. The OSC-IVM culture condition was composed of 100,000 OSCs in suspension culture with human chorionic gonadotropin (hCG), recombinant follicle stimulating hormone (rFSH), androstenedione, and doxycycline supplementation. The Media-IVM control lacked OSCs and contained the same supplementation. A limited set of in vivo matured MII oocytes were donated for comparative evaluation. Endpoints consisted of MII formation rate, morphological and spindle quality assessment, and gene expression analysis compared to in vitro and in vivo controls. RESULTS: OSC-IVM resulted in a statistically significant improvement in MII formation rate compared to the Media-IVM control, with no apparent effect on morphology or spindle assembly. OSC-IVM MII oocytes displayed a closer transcriptomic maturity signature to IVF-MII controls than Media-IVM control MII oocytes. The gene expression profile of OSCs was modulated in the presence of oocytes, displaying culture- and time-dependent differential gene expression during IVM. CONCLUSION: The OSC-IVM platform is a novel tool for rescue maturation of human oocytes, yielding oocytes with improved nuclear maturation and a closer transcriptomic resemblance to in vivo matured oocytes, indicating a potential enhancement in oocyte cytoplasmic maturation. These improvements on oocyte quality after OSC-IVM are possibly occurring through bidirectional crosstalk of cumulus-free oocytes and ovarian support cells.

Spin-Orbit Torque in Single-Molecule Junctions from ab Initio.

The use of electric fields applied across magnetic heterojunctions that lack spatial inversion symmetry has been previously proposed as a nonmagnetic means of controlling localized magnetic moments through spin-orbit torques (SOT). The implementation of this concept at the single-molecule level has remained a challenge, however. Here, we present first-principles calculations of SOT in a single-molecule junction under bias and beyond linear response. Employing a self-consistency scheme invoking density functional theory and nonequilibrium Green's function theory including spin-orbit interaction, we compute the change of the magnetization with the bias voltage and the associated current-induced SOT. Within the linear regime our quantitative estimates for the SOT in single-molecule junctions yield values similar to those known for magnetic interfaces. Our findings contribute to an improved microscopic understanding of SOT in single molecules.

Pandemic preparedness through vaccine development for avian influenza viruses.

Influenza A viruses pose a significant threat to global health, impacting both humans and animals. Zoonotic transmission, particularly from swine and avian species, is the primary source of human influenza outbreaks. Notably, avian influenza viruses of the H5N1, H7N9, and H9N2 subtypes are of pandemic concern through their global spread and sporadic human infections. Preventing and controlling these viruses is critical due to their high threat level. Vaccination remains the most effective strategy for influenza prevention and control in humans, despite varying vaccine efficacy across strains. This review focuses specifically on pandemic preparedness for avian influenza viruses. We delve into vaccines tested in animal models and summarize clinical trials conducted on H5N1, H7N9, and H9N2 vaccines in humans.

Oscillometric devices vs. arterial Doppler in measuring the ankle-arm index for the diagnosis of peripheral arterial disease. / Dispositivos oscilométricos frente a Doppler arterial en la medida del índice tobillo-brazo para el diagnóstico de la enfermedad arterial periférica.

INTRODUCTION: Peripheral arterial disease is a marker of vascular damage that is diagnosed by measuring the ankle-brachial index. The aim of this study was to determine the validity and agreement of the MESI ABPI-MD and Microlife WatchBP® office-ABI oscillometric devices with respect to the gold standard arterial Doppler. MATERIALS AND METHODS: Observational, cross-sectional, descriptive study of inpatients who underwent ABI measurement with the three devices. Values are considered normal between 1-1.4, indeterminate between 0.91-0.99 and pathological ≤0.9 and >1.4. RESULTS: A total of 187 patients (54.4% male) with a mean age of 66 years were included. The Doppler results were inferior to those of the oscillometric devices (median [IQR] 1.1 [0.2] vs. 1.2 [0.2], P<.05), with no significant differences between the automated devices (P=.29 for the right lower limb and P=.342 for the left lower limb). Both devices had high specificity (96.5-99.2%) and low sensitivity (29.5-45.4%). The correlation of the results was good-moderate for MESI and moderate for Microlife. The agreement between the two was acceptable-moderate. CONCLUSION: Automated oscillometric devices could be useful in asymptomatic patients as an alternative to arterial Doppler.

A devastating blow: personal reflections on Argentina's scientific decline.

As an Argentine scientist, the defunding of CONICET and INTA feels like a blow to progress and our future. Despite free education, these cuts force talented researchers to seek opportunities abroad. Argentina's history of scientific achievement, from Nobel Prizes to COVID-19 vaccines, is at risk. Defunding science weakens our ability to solve problems and compete globally.

Specific nanoprobe design for MRI: Targeting laminin in the blood-brain barrier to follow alteration due to neuroinflammation.

Chronic neuroinflammation is characterized by increased blood-brain barrier (BBB) permeability, leading to molecular changes in the central nervous system that can be explored with biomarkers of active neuroinflammatory processes. Magnetic resonance imaging (MRI) has contributed to detecting lesions and permeability of the BBB. Ultra-small superparamagnetic particles of iron oxide (USPIO) are used as contrast agents to improve MRI observations. Therefore, we validate the interaction of peptide-88 with laminin, vectorized on USPIO, to explore BBB molecular alterations occurring during neuroinflammation as a potential tool for use in MRI. The specific labeling of NPS-P88 was verified in endothelial cells (hCMEC/D3) and astrocytes (T98G) under inflammation induced by interleukin 1ß (IL-1ß) for 3 and 24 hours. IL-1ß for 3 hours in hCMEC/D3 cells increased their co-localization with NPS-P88, compared with controls. At 24 hours, no significant differences were observed between groups. In T98G cells, NPS-P88 showed similar nonspecific labeling among treatments. These results indicate that NPS-P88 has a higher affinity towards brain endothelial cells than astrocytes under inflammation. This affinity decreases over time with reduced laminin expression. In vivo results suggest that following a 30-minute post-injection, there is an increased presence of NPS-P88 in the blood and brain, diminishing over time. Lastly, EAE animals displayed a significant accumulation of NPS-P88 in MRI, primarily in the cortex, attributed to inflammation and disruption of the BBB. Altogether, these results revealed NPS-P88 as a biomarker to evaluate changes in the BBB due to neuroinflammation by MRI in biological models targeting laminin.

Analysis of the elderly pedestrian traffic accidents in urban scenarios: the case of the Spanish municipalities.

As the elderly population grows, there is a greater concern for their safety on the roads. This is particularly important for elderly pedestrians who are more vulnerable to accidents. In Spain, one of the most aged countries in the world, the elderly accounted for 70% of all pedestrian deaths in 2019. In this study, the focus was on analysing the occurrence of elderly pedestrian-vehicle collisions in Spanish municipalities and how it is related to the built environment. The study used the hurdle negative binomial model to analyse the number of elderly and non-elderly pedestrian accidents per municipality in 2016-2019. The exploratory analysis showed that cities above 50,000 inhabitants were safer for the elderly, and larger provincial capitals had lower elderly pedestrian traffic accident rates. The occurrence of all pedestrian traffic accidents was linked to the socio-demographic features. For elderly pedestrians, land use was found to be influential, with a lower proportion of land covered by manufacturing and service activities linked to a smaller number of accidents. Results showed that improving road safety for older pedestrians may not necessarily compromise the situation for the rest of population. Hence, policymakers should focus on infrastructure improvements adapted to the needs of elderly pedestrians.

In vitro effect of diazoxon on cell signaling and second messengers in Nile tilapia (Oreochromis niloticus) leukocytes.

The physiological and molecular responses of leukocytes are altered by organophosphate pesticides. Some reports have shown that diazinon causes immunotoxic effects; diazoxon, the oxon metabolite of diazinon, is attributed to influence the immune response by affecting the leukocyte cholinergic system. In this study, the in vitro effects of diazoxon on molecules involved in cell signaling (cAMP, IP3, DAG, JAK1, and STAT3), which play a crucial role in the activation, differentiation, and survival of leukocytes, were evaluated. Data indicate that diazoxon leads to a decrease in cAMP concentration and an increase in basal IP3 levels. However, diazoxon does not affect basal levels of JAK1 and STAT3 phosphorylation. Instead, diazoxon inhibits leukocyte responsiveness to phorbol myristate acetate and ionomycin, substances that, under normal conditions, enhance JAK/STAT signaling. These findings demonstrate that diazoxon significantly affects key molecular parameters related to cell signaling.

Do the humeral radiographic changes at 5-year follow-up affect the clinical outcomes of press-fit humeral stems in primary reverse shoulder arthroplasties?

INTRODUCTION: The purposes of this study were to analyze and compare the functional outcomes and radiological changes around the press-fit humeral components in two contemporary medialized reverse total shoulder arthroplasty (RTSA) systems at a minimum of 5-year follow-up. MATERIALS AND METHODS: Between December 2003 and December 2015, 249 consecutive RTSAs were performed at our hospital. Of these, 68 primary uncemented RTSA met our inclusion criteria. The Constant-Murley score (CMS), the modified Constant score, a visual analog scale (VAS) and active shoulder range of motion (ROM) were measured pre- and postoperatively. Radiological assessment was performed by plain radiographs at a minimum of 5 years postoperatively. RESULTS: At a mean follow-up of 80.2 months, there was no significant difference (p = .59) between the postoperative functional scores and range of motion of the two groups (Delta Xtend and Lima SMR). Radiological data of stress-shielding were observed in 38 patients (55.9%) being slightly more frequent in the Lima SMR group (21 patients) than in the Delta Xtend group (17 patients) (p = .62). CONCLUSIONS: Our study shows that the good functional results are similar between the two uncemented RTSA systems used and that they do not depend on the presence of radiological changes (stress-shielding) in the humeral stem at a minimum 5-year follow-up.

Long-term follow-up of total hip arthroplasty using polyethylene-ceramic composite (sandwich) liner.

INTRODUCTION: Ceramic-on-ceramic bearings have been widely used since their introduction in the 1970s. First-generation ceramics have very high fracture (breakage) rates. To overcome this, in the 1990s, modular cotyloid insert designs were developed, consisting of a ceramic and polyethylene composite (sandwich-type) liner; however, high implant fracture rates were observed in the medium term. We aimed to estimate the cumulative incidences of revision surgery (implant failure) and implant failure due to fractures, survival rates (time-to-revision surgery and time-to-fracture), and the long-term clinical and radiological outcomes in our series. METHODS: This was an observational, longitudinal, ambispective, single-centre study based on patients who underwent primary total hip arthroplasty (THA) using a sandwich-type liner (Cerasul), only available in our tertiary hospital between January 1999 and December 2002. Cumulative incidences were estimated and the 95% confidence interval (95% CI) was calculated. The Kaplan-Meier method was used to assess the time-to-revision surgery and time-to-fracture. RESULTS: 54 patients (49 men) were included, accounting for 59 sandwich-type linear implants. The mean (range) age was 47.4 (22-57) years. The primary THA indications were osteoarthritis (28 patients), osteonecrosis (14), childhood pathology sequelae (11), and inflammatory arthritis (6). The cumulative incidence of revision surgery by implants was 8.5% (5/59, 95% CI, 3.5-19.2%), 9.3% by patients (5/54, 95% CI, 4.0-19.9%), and 5.1% by implant fractures (3/59, 95%CI, 1.7-13.9%). The median (Interquartile Range, IQR) time-to-revision surgery was 158 (72.5-161) months, and the time to fracture was 182 (138-215) months. All primary THAs had good clinical and long-term survival outcomes. All implants had signs of solid fixation. CONCLUSIONS: After a 20-year follow-up period, the polyethylene-ceramic sandwich-type liner showed a long survival rate and low cumulative incidence of implant fracture; however, implant fractures remain the main complication. Orthopaedic surgeons should be aware that some patients still have this type of prosthesis and must be capable of responding quickly if a fracture occurs.