Allometric tissue-scale forces activate mechanoresponsive immune cells to drive pathological foreign body response to biomedical implants

For decades, it has been assumed that the foreign body response (FBR) to biomedical implants is primarily a reaction to the chemical and mechanical properties of the implant. Here, we show for the first time that a third independent variable, allometric tissue-scale forces (which increase exponentially with body size), can drive the biology of FBR in humans. We first demonstrate that pathological FBR in humans is mediated by immune cell-specific Rac2 mechanotransduction signaling, independent of implant chemistry or mechanical properties. We then show that mice, which are typically poor models of human FBR, can be made to induce a strikingly human-like pathological FBR by altering these extrinsic tissue forces. Altering these extrinsic tissue forces alone activates Rac2 signaling in a unique subpopulation of immune cells and results in a human-like pathological FBR at the molecular, cellular, and local tissue levels. Finally, we demonstrate that blocking Rac2 signaling negates the effect of increased tissue forces, dramatically reducing FBR. These findings highlight a previously unsuspected mechanism for pathological FBR and may have profound implications for the design and safety of all implantable devices in humans.

Double Magnet Ingestion Causing Intestinal Perforation with Peritonitis: Case Report and Review of the Literature

Introduction. Foreign body ingestion is a common pediatric complain, and most can be passed spontaneously; however, magnetic object ingestion is rather rare, and they can cause severe complications when multiple magnets are ingested, as they lead to entrapment of bowel walls between them, causing ischemia, pressure necrosis, perforation, and fistula formation. Case Presentation. Herein, we present a case of a 16-month-old female patient presented to our department complaining of continuous vomiting for two days along with fever and irritability. X-ray revealed dilated bowel loops with a radioopaque foreign body in the right lower quadrant. After discussing with the parents, exploratory laparotomy was done, showing two bowel perforations at the site of the magnets. Affected bowel was resected with anastomosis. The patient was discharged after 3 days with an uneventful recovery. Discussion. The diagnosis and management of magnet ingestion differ from those of small foreign bodies, which are usually managed conservatively by watchful waiting. Usually, the diagnosis is done due to complications such as peritonitis and death. On the other hand, management depends on the number, size, magnetic field, and shape of the magnet, and whether it has passed the pylorus or not. Conclusion. It is important to establish the diagnosis of this condition as early as possible to prevent complications. Despite the efforts that were made to try to prevent and minimize the risk of magnet ingestion, more investigations are required to reach a common and united strategy for management of such conditions.

FOREIGN BODY INCIDENCE IN PREGNANT COWS AND BUFFALOS

Clinical study for (105) pregnant and (32) buffalo suffering from reticulopertonitis which are operated for foreign body removal by rumenotomy in different pregnancy stages. Result shown that the late stage pregnancy is the highest inicdence and all operated animals had no any complications and some of them delivered normally after 10 - 16 hr. and other within few days, this indicate that rumenotomy could be done at any stage of pregnancy even within few hours before parturition.

Foreign body aspiration in Israeli children during the COVID-19 pandemic

Background: Since the outbreak of the Coronavirus disease 2019 (COVID-19) pandemic, there has been a decline in pediatric emergency department visits. Our aim was to assess the pattern of pediatric foreign body aspiration (FBA) during the first year of the COVID-19, in comparison to the prior years. Methods: In this retrospective multicenter study, we compared the number of children that presented with FBA during the COVID-19 year (March 1st, 2020 to February 28, 2021), to the annual average of the years 2016-2019. We also compared the lockdown periods to the post-lockdown periods and the percentage of missed FBA, proven FBA, and flexible bronchoscopy as the removal procedure. Results: 345 children with FBA from six centers were included, 276 in the pre-COVID-19 years (average 69 per year) and 69 in the COVID-19 year. There was no difference in the prevalence of FBA between the COVID-19 year and any of the prior four years. Examining the lockdown effect, the monthly incidence of FBA dropped from a pre-COVID-19 average of 5.75 cases to 5.1 cases during lockdown periods and increased to 6.3 cases in post-lockdown periods. No difference in the percentage of missed FB or proven FB was observed. There was a significant rise in the usage of flexible bronchoscopy as the removal procedure (Average of 15.4% vs 30.4%, p=0.001) Conclusion: There was no difference in the prevalence of FBA during the COVID-19 year. However, there were fewer cases during lockdown periods, compared to post-lockdown periods, presumably related to better parental supervision.

Evaluating the Biocompatibility of an Injectable Wound Matrix in a Murine Model

(1) Background: Developing a high-quality, injectable biomaterial that is labor-saving, cost-efficient, and patient-ready is highly desirable. Our research group has previously developed a collagen-based injectable scaffold for the treatment of a variety of wounds including wounds with deep and irregular beds. Here, we investigated the biocompatibility of our liquid scaffold in mice and compared the results to a commercially available injectable granular collagen-based product. (2) Methods: Scaffolds were applied in sub-dermal pockets on the dorsum of mice. To examine the interaction between the scaffolds and the host tissue, samples were harvested after 1 and 2 weeks and stained for collagen content using Masson’s Trichrome staining. Immunofluorescence staining and quantification were performed to assess the type and number of cells infiltrating each scaffold. (3) Results: Histological evaluation after 1 and 2 weeks demonstrated early and efficient integration of our liquid scaffold with no evident adverse foreign body reaction. This rapid incorporation was accompanied by significant cellular infiltration of stromal and immune cells into the scaffold when compared to the commercial product (p < 0.01) and the control group (p < 0.05). Contrarily, the commercial scaffold induced a foreign body reaction as it was surrounded by a capsule-like, dense cellular layer during the 2-week period, resulting in delayed integration and hampered cellular infiltration. (4) Conclusion: Results obtained from this study demonstrate the potential use of our liquid scaffold as an advanced injectable wound matrix for the management of skin wounds with complex geometries.

The Erroneous Appearance of Silver Nitrate on CT Imaging in Patients with Severe Otitis Externa; A Case Series

Introduction Silver nitrate is commonly used within otolaryngology to treat granulation tissue in severe otitis externa. It appears radio-opaque on CT (computed tomography) imaging and therefore can mimic bony fragments and foreign bodies. This is particularly cumbersome when the phenomena correlates to the clinical complaint. Discussion We report two cases of 73-year-old and 75-year-old males who presented with chronic otalgia and discharge. Granulation tissue in the external auditory canal was identified and chemically cauterised with silver nitrate. Subsequent CT petrous bones demonstrated an unidentified foreign body in the canal with extensive soft tissue swelling giving an impression of a wick in situ and “minor bony erosion in the left external acoustic canal” respectively. An additional CT of a 57-year-old female who had been treated with silver nitrate for granulomatous tissue reported “multiple highly radiopaque foci in the external auditory canal, suggestive of foreign body”. Though relatively unknown, this phenomenon has been reported in literature. However, there are few reports of silver nitrate artefacts in CT images of the head no cases in the context of otitis externa. Our patients avoided further imaging or surgery following clarification with the radiologists and symptomatic improvement with long-term intravenous antibiotics. Conclusion Given the prevalence of CT imaging and cauterization in otolaryngology, we recommend contemporaneously documenting the use of silver nitrate and highlighting this on request forms to avoid alarming erroneous reports, unnecessary investigation and surgical procedures. We also recommend, where clinically acceptable, to use silver nitrate prior to imaging.