The Use of Bone Marrow Concentrate in the Treatment of Full-Thickness Chondral Defects

HSS Journal ® - This article is a critical analysis of a study, “Minimally Manipulated Bone Marrow Concentrate Compared with Microfracture Treatment of Full-Thickness Chondral Defects: A...     

Ultrasound Evaluation of the Protector Role of the Pronator Quadratus Suture in Volar Plating

The main complication of volar locking plates for distal radius fractures is flexor tendon rupture. The flexor pollicis longus (FPL) is the most commonly ruptured. Repair of the pronator quadratus (PQ) is one of the ways to prevent tendon rupture. The main purpose of this series was to evaluate the role of PQ repair after volar plating to prevent flexor tendon rupture using ultrasound (US). This work was a mono‐operator prospective series of 20 consecutive patients with volar locking plates for distal radius fracture between September 2014 and May 2015. The PQ was repaired in all patients. A clinical, ultrasound, and perioperative evaluation of the flexor tendon was performed by this same surgeon. There was no flexor tendon rupture or tenosynovitis. There were no type A cases, which are characterized by contact between the plate and the FPL, and mostly type C cases, which are characterized by no contact between the plate and the FPL on US imaging. The suture of the PQ was sustainable over time when we removed the plate. Pronator quadratus repair is one of the ways to prevent flexor tendon rupture after volar plating. The outward‐running suture is an effective technique for repairing the PQ. Ultrasound may be helpful during follow‐up to detect asymptomatic flexor tendon irritation.     

Immune Response to Persistent Staphyloccocus Aureus Periprosthetic Joint Infection in a Mouse Tibial Implant Model

Staphyloccocus aureus is one of the major pathogens in orthopedic periprosthetic joint infection (PJI), a devastating complication of total joint arthroplasty that often results in chronic and persistent infections that are refractory to antibiotics and require surgical interventions. Biofilm formation has been extensively investigated as a reason for persistent infection. The cellular composition, activation status, cytokine profile, and role of the immune response during persistent S. aureus PJI are incompletely understood. In this study, we used histology, multiparametric flow cytometry, and gene expression analysis to characterize the immune response in a clinically relevant orthopedic PJI model. We tested the hypothesis that persistent S. aureus infection induces feedback mechanisms that suppress immune cell activation, thereby affecting the course of infection. Surprisingly, persistent infection was characterized by strikingly high cytokine gene expression indicative of robust activation of multiple components of innate and adaptive immunity, along with ongoing severe neutrophil-dominated inflammation, in infected joint and bone tissues. Activation and expansion of draining lymph nodes and a bone marrow stress granulopoiesis reaction were also maintained during late phase infection. In parallel, feedback mechanisms involving T-cell inhibitory receptors and exhaustion markers, suppressive cytokines, and regulatory T cells were activated and associated with decreased T-cell proliferation and tissue infiltration during the persistent phase of infection. These results identify the cellular and molecular components of the mouse immune response to persistent S. aureus PJI and indicate that neutrophil infiltration, inflammatory cytokine responses, and ongoing lymph node and bone marrow reactions are insufficient to clear infection and that immune effector mechanisms are suppressed by feedback inhibitory pathways. These immune-suppressive mechanisms are associated with diminished T-cell proliferation and tissue infiltration and can be targeted as part of adjuvant immunotherapeutic strategies in combination with debridement of biofilm, antibiotics, and other therapeutic modalities to promote eradication of infection. © 2021 American Society for Bone and Mineral Research (ASBMR).     

The Distance between the Pylorus and Left Vagus Nerve during Sleeve Gastrectomy

The sleeve gastrectomy (SG) can be performed with or without antral preservation (distance from the pylorus <50 mm). The objective of this study was to evaluate the distance between the pylorus and the end of the left vagus nerve in order to determine whether it could be used as a constant anatomical landmark to start gastric transection. This was a prospective, nonrandomized study of 120 patients undergoing SG from January to October 2018. The distance measurement between pylorus and vagus nerve was performed at the beginning of the SG. The primary endpoint was the distance between the beginning of the pylorus and the end of the second branch of the vagus nerve on the upper edge of the antrum. The secondary endpoints was the correlation factors between the preoperative data and the position of the end of the vagus nerve. A total of 120 patients, with a mean body mass index of 42.2 kg/m², underwent primary SG. The mean distance between pylorus and the end of the vagus nerve was 50.4 mm (35–64) on the upper part of the antrum. When considering the inferior part of the antrum, the minimum distance was 50 mm. No correlations were found between preoperative data and distance measurements. The vagus nerve can be considered as a constant and reliable anatomical landmark for performing SG with antral preservation. However, no correlation was found between the preoperative data and the location of the end of the vagus nerve. Clin. Anat. 33:562–566, 2020. © 2019 Wiley Periodicals, Inc.     

Learning and memory performance following acute intranasal insulin administration in abstinent smokers

The highest incidence of relapse to smoking occurs within the first 2 weeks of a cessation attempt. In addition to enhanced nicotine craving, this phase of smoking cessation is also marked by learning and memory dysfunction. Many smokers are not able to overcome these symptoms, and they relapse to smoking shortly after trying to quit. In two clinical studies, we evaluated intranasal insulin for efficacy in improving learning and memory function during nicotine withdrawal. Our first study was a crossover evaluation (N = 19) following 20 hr of smoking abstinence. Study 2 was a parallel design study (N = 50) following 16 hr of abstinence. Intranasal insulin (60 IU) dose was administered in both studies and cognitive function was measured using California Verbal Learning Test‐II. Intranasal insulin did not improve learning over the 5 verbal learning trials. In addition, intranasal insulin did not improve either short‐ or long‐delay recall in either study. In summary, the one‐time administration of intranasal insulin does not improve verbal learning and memory in smokers. Whether longer administration schedules may be of benefit should be evaluated in future studies.     

Adaptation of salivary Lactobacillus strains to xylitol

OBJECTIVE: Acid production from sugars is one of the virulence factors of cariogenic bacteria. To eliminate this factor, many authors have suggested using sugar substitutes like xylitol, which is not fermented by most oral bacteria. The aim of this work was to investigate whether oral strains of lactobacilli unable to utilise xylitol could become able to utilise this polyol. DESIGN: Twenty-eight oral strains and six ATCC strains of lactobacilli were tested. None was initially able to produce acids from xylitol. Media containing only xylitol was used in order to see if an adaptation was possible. The acid production from xylitol was measured by recording the pH variations of the culture medium. The acids produced were identified by HPLC. RESULTS: After a 15-days culture, 10 strains produced acids. After a 40-days culture, 11 more strains produced acid. When acid production occurred, lactic, formic, acetic, propionic and butyric acids were the organic acids formed by all the strains. CONCLUSIONS: Adaptation of oral strains of lactobacilli to xylitol can occur in vitro.     

Stage‐specific requirement for cyclin D1 in glial progenitor cells of the cerebral cortex

Despite the vast abundance of glial progenitor cells in the mouse brain parenchyma, little is known about the molecular mechanisms driving their proliferation in the adult. Here we unravel a critical role of the G1 cell cycle regulator cyclin D1 in controlling cell division of glial cells in the cortical grey matter. We detect cyclin D1 expression in Olig2‐immunopositive (Olig2+) oligodendrocyte progenitor cells, as well as in Iba1+ microglia and S100β+ astrocytes in cortices of 3‐month‐old mice. Analysis of cyclin D1‐deficient mice reveals a cell and stage‐specific molecular control of cell cycle progression in the various glial lineages. While proliferation of fast dividing Olig2+ cells at early postnatal stages becomes gradually dependent on cyclin D1, this particular G1 regulator is strictly required for the slow divisions of Olig2+/NG2+ oligodendrocyte progenitors in the adult cerebral cortex. Further, we find that the population of mature oligodendrocytes is markedly reduced in the absence of cyclin D1, leading to a significant decrease in the number of myelinated axons in both the prefrontal cortex and the corpus callosum of 8‐month‐old mutant mice. In contrast, the pool of Iba1+ cells is diminished already at postnatal day 3 in the absence of cyclin D1, while the number of S100β+ astrocytes remains unchanged in the mutant. GLIA 2014;62:829–839