Leveraging single cell sequencing to unravel intra-tumour heterogeneity and tumour evolution in human cancers

Intra-tumour heterogeneity and tumour evolution are well-documented phenomena in human cancers. While the advent of next-generation sequencing technologies has facilitated the large-scale capture of genomic data, the field of single cell genomics is nascent but rapidly advancing and generating many new insights into the complex molecular mechanisms of tumour biology. In this review, we provide an overview of current single cell DNA sequencing technologies, exploring how recent methodological advancements have enumerated new insights into intra-tumour heterogeneity and tumour evolution. Areas highlighted include the potential power of single cell genome sequencing studies to explore evolutionary dynamics contributing to tumourigenesis through to progression, metastasis and therapy resistance. We also explore the use of in-situ sequencing technologies to study intra-tumour heterogeneity in a spatial context, as well as examining the use of single cell genomics to perform lineage tracing in both normal and malignant tissues. Finally, we consider the use of multi-modal single cell sequencing technologies. Taken together, it is hoped that these many facets of single cell genome sequencing will improve our understanding of tumourigenesis, progression and lethality in cancer leading to the development of novel therapies. This article is protected by copyright. All rights reserved

Prognostic relevance of MMP-2 (72-kD collagenase IV) in gastric cancer

The association of MMP-2 (matrix metalloproteinase 2, 72-kD collagenase IV) with invasive and metastatic capacity of tumor cells has implicated a potential role in the prognosis for cancer patients. However, no larger study has been done to prove this hypothesis. The present study was therefore designed to investigate the prognostic impact of MMP-2 in a prospective series of 203 gastric cancer patients. MMP-2 expression was measured immunohistochemically and scored semiquantitatively (score 0-3) in carcinoma cells, and results were correlated with clinicopathological tumor parameters and parameters of the urokinase-type plasminogen activator (uPA) system. Survival analyses were done using the Kaplan-Meier method (log-rank statistics) and multivariate Cox analysis. Significant correlations were found for MMP-2 and Lauren's classification, M stage and proteases/inhibitors of the uPA system in the primary tumor. Kaplan-Meier analysis revealed an association of increasing MMP-2 expression with worse prognosis. This was especially seen in patients with a parallel high expression of uPA receptor. However, differences in survival probabilities between low and high MMP-2 levels were not significant. In a separate analysis of diffuse-type cancers, MMP-2 was significantly associated with disease-free (p = 0.0056) and overall survival (p = 0.0426). Multivariately, MMP-2 was not an independent parameter. Our results demonstrate that there is an association of immunohistochemical detection of MMP-2 with prognosis of cancer patients. For diffuse gastric cancers, it is a significant prognostic parameter, however, not of independent impact. The study further suggests that consideration of interrelated tumor-associated proteases like uPA receptor in combination with MMP-2 may improve its prognostic power

Prevention of Surgical Site Infection: A Ten-Step Approach

Surgical site infection (SSI) is a common cause of morbidity and mortality in patients undergoing surgery. Similarly, periprosthetic joint infection (PJI), is a major cause of failure after total joint arthroplasty (TJA). As the annual volume of TJA procedures is projected to rise, so will the rate of subsequent SSI and PJI. Currently, prevention has been identified as the single most important strategy for combating SSI/PJI. Hence, the present article will serve as a summary of an evidence-based ten-step approach for SSI/PJI prevention that may help orthopedic surgeons with their infection prevention strategies

The protympanum, protiniculum and subtensor recess: an endoscopic morphological anatomy study

Objectives: An anatomical study was performed to describe the endoscopic anatomy and variations of the protympanum, including classification of the protiniculum and subtensor recess. Methods: A retrospective review was conducted of video recordings of cadaveric dissections and surgical procedures, which included visualisation of the protympanum, across 4 tertiary university referral centres over a 16-month period. A total of 97 ears were used in the analysis. Results: A quadrangular conformation of the protympanum was seen in 60 per cent of ears and a triangular conformation in 40 per cent. The protiniculum was type A (ridge) in 58 per cent, type B (bridge) in 23 per cent and type C (absent) in 19 per cent. The subtensor recess was type A (absent) in 30 per cent, type B (shallow) in 48 per cent and type C (deep) in 22 per cent. Conclusion: The protympanum is an area that has been ignored for many years because of difficulties in visualising it with an operating microscope. However, modern endoscopic equipment has changed this, providing detailed anatomical knowledge fundamental to ensuring the safety of endoscopic surgical procedures in the region

Comparative study of locking neutralization plate construct versus tension band wiring with a cannulated screw for patella fractures: Experimental and finite element analysis

Transverse patella fractures, accounting for approximately 1% of Orthopedic injuries, pose intricate challenges due to their vital role in knee mechanics. This study aimed to compare the biomechanical performance of a construct, integrating cannulated screws and an anterior locking neutralization plate, with the conventional tension band wiring technique for treating these fractures. Experimental testing and Finite Element Analysis were employed to evaluate the constructs and gain profound insights into their mechanical behavior. Sixteen cadaveric knees were prepared, and transverse patella fractures were induced at the midpoints using a saw. The plate construct and tension band wire fixation were randomly assigned to the specimens. A cyclic test evaluated the implants' durability and stability, simulating knee movement during extension and flexion. Tensile testing assessed the implants' maximum failure force after cyclic testing, while Finite Element Analysis provided detailed insights into stress distribution and deformation patterns. Statistical analysis was exclusively performed for the experimental data. Results showed the plate enhanced stability with significantly lower deformation (0.09 ± 0.12 mm) compared to wire fixation (0.77 ± 0.54 mm) after 500 cycles (p = 0.004). In tensile testing, the construct also demonstrated higher failure resistance (1359 ± 21.53 N) than wire fixation (780.1 ± 22.62N) (p = 0.007). Finite Element Analysis highlighted distinct stress patterns, validating the construct's superiority. This research presents a promising treatment approach for transverse patella fractures with potential clinical impact and future research prospects. This study presents a promising advancement in addressing the intricate challenges of transverse patella fractures, with implications for refining clinical practice. The construct's improved stability and resistance to failure offer potential benefits in postoperative management and patient outcomes

Endoscopic Middle Ear Surgery: Tips and Pearls

Program Description: Middle ear surgery can generally be performed with the aid of an operating microscope. However, under a potentially minimally invasive trans-canal approach, it is very difficult to operate on several sites using a microscope alone unless the surrounding bone is removed and retro-auricular approaches are performed. Such sites may include the epitympanum as well as the inferior and posterior parts of the mesotympanum. Although it has been more than 15 years since the introduction of operative endoscopy to middle ear surgery there is still a very limited role for the endoscope in the surgical management of middle ear disease across the globe. There are several possible reasons for that, such as the current idea of a limited and marginal role for endoscopes in middle ear surgery, a potentially long learning curve through the hassles and tribulations of adapting newer techniques and newer instrumentation, and some resistance, especially with otologists who are very comfortable with the use of microscopes. The operating microscope provides a very good quality magnified image in a straight line, however, the surgeon\u2019s field of view is limited to the narrowest segment of the ear canal when using a transcanal approach. On the other hand, endoscopes also provide a magnified vision that enables the ability to change rapidly from a close-up to a wide angle view, just by going closer or by withdrawing the instrument. Further, it provides an all-round vision to the surgeon who can rotate angled endoscopes to visualize the deep and hidden structures. In this miniseminar, we are going to discuss, with the help of very nice quality surgical movies, endoscopic anatomic dissection images and videos, virtual reality objects and also augmented reality capability the current techniques for endoscopic middle ear dissection, and surgical management of several middle ear diseases, such as tympanic membrane perforations, cholesteatomas, ossicular chain reconstruction and also stapedotomies, all performed with endoscopes discussing and commenting the equipment needed, surgical indications, also showing the potential advantages and disadvantages of the procedures, postoperative care and results and some interesting tips and pearls regarding this new way to surgically manage middle ear diseases. Educational Objectives: 1) Learn and review the endoscopic anatomy of the middle ear, discussing anatomic landmarks. 2) Identify the actual indications and limitations of this minimally invasive approach. 3) Describe and demonstrate step-wise endoscopic middle ear approaches for several diseases of this area

Direct Anterior Approach Utilizing a Bikini Incision has Less Wound Related Complications in Patients with High BMI

Introduction: Direct anterior approach (DAA) total hip arthroplasty (THA) can be performed through a traditional vertical skin incision, situating the proximal incision at the hip flexion crease, or a horizontal (bikini) skin incision, situating the incision slightly distal and parallel to the hip flexion crease. The dissection beyond the subcutaneous layer is identical for both methods. Objective: The purpose of this study was to compare these approaches, performed by an experienced single surgeon, in terms of overall wound complications and patient-reported esthetics 6-months post-operatively. It was hypothesized that the bikini incision would result in less wound complications and improved cosmesis due to decreased applied tension from the hip flexion crease. Methods: A case-control retrospective study was conducted and 86 bikini DAA patients were matched 3:1 to 230 conventional DAA patients for gender, age, body mass index (BMI), and American Society of Anesthesiologists score. The outcomes evaluated included wound complications, acute periprosthetic joint infection, transfusion, length of surgery, and dysesthesia with an additional subset analysis for obese patients (BMI \u3e30kg/m2). Patients rated incision cosmesis 6 months post-operatively using a Patient Scar Assessment Scale and the Vancouver scar assessment scale. Results: Bikini patients had lower rates of delayed wound healing compared to conventional incision (2.3% vs. 6.1%; p=0.087). This difference was statistically significant (0% vs. 16.6%; p\u3c0.05) in obese patients with no difference in incision cosmesis in either analysis. Discussion: The bikini incision could offer safety benefits in selected patients (BMI \u3e30kg/m2) undergoing DAA THA by decreasing wound complications while preserving cosmesis

Current relevance of biomarkers in diagnosis of periprosthetic joint infection: an update.

With a significant rise in the number of arthroplasty procedures performed worldwide, the increasing revision burden posed by periprosthetic joint infection (PJI) is a matter of growing concern. In spite of various attempts to diagnose PJI, there are no defined tests that can be called a gold standard. Given the importance of early diagnosis in PJI, newer tests and biomarkers have been introduced to improve cumulative diagnostic accuracy. Novel biomarkers like calprotectin, lipocalcin, monocyte-to-lymphocyte ratio, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and platelet-to-mean platelet volume ratio have demonstrated a potential as diagnostic biomarkers for PJI. This article discusses the relevance of available and newly described diagnostic biomarkers to provide a perspective on the practical applicability in current medical practice, as well as highlights some recent advances in biomarkers for the diagnosis of PJI