Feasibility of perforator flaps in Day surgery. A retrospective study through a two-years' experience

BACKGROUND

Day surgery is developing and its popularity is increasing for a variety of reasons: economic constraints, changes in professional practices, a greater adhesion of the patient. In an era of progress in surgical procedures, pedicled-perforator flaps reducing donor site morbidity and avoiding micro-anastomosis could take their place in Day surgery if planned and managed by an experienced team.

METHODS

In the period January 2019 to January 2021, we performed perforator flaps for soft tissue coverage in ambulatory setting. The patients were included retrospectively and data were collected by reviewing the medical records. Major and minor complications were recorded.

RESULTS

The retrospective cohort included 32 surgical procedures in 32 patients. In all cases, perforator flaps were realized for resurfacing soft tissue defects consequent to oncodermatology surgery (84.3%), soft tissue sarcoma surgery (12.5%), invasive ductal breast carcinoma (3.1%). Major complications needing a surgical revision overcame 3/32 times (9.4%). In these cases, a failure requiring the drop off the flap overcame once. The average wound healing time was of 33 days (15-90) and the mean duration of follow-up was 9.6 months (1-22).

CONCLUSION

The low complication rate in our series suggests that this first experience on perforator flaps in outpatient surgery is promising in terms of safety and feasibility. Day surgery could be a practical option for this type of surgical procedures avoiding the conventional department's saturation and allowing the delivery of proper surgical cares.

Natural, biphasic calcium phosphate from fish bones for enamel remineralization and dentin tubules occlusion

OBJECTIVES

A calcium phosphate extracted from fish bones (CaP-N) was evaluated for enamel remineralization and dentinal tubules occlusion.

METHODS

CaP-N was characterized by assessing morphology by SEM, crystallinity by PXRD, and composition by ICP-OES. CaP-N morphology, crystallinity, ion release, and pH changes over time in neutral and acidic solutions were studied. CaP-N was then tested to assess remineralization and dentinal tubules occlusion on demineralized human enamel and dentin specimens (n = 6). Synthetic calcium phosphate in form of stoichiometric hydroxyapatite nanoparticles (CaP-S) and tap water were positive and negative controls, respectively. After treatment (brush every 12 h for 5d and storage in Dulbecco's modified PBS), specimens' morphology and surface composition were assessed (by SEM-EDS), while the viscoelastic behavior was evaluated with microindentation and DMA.

RESULTS

CaP-N consisted of rounded microparticles (200 nm - 1 µm) composed of 33 wt% hydroxyapatite and 67 wt% β-tricalcium phosphate. In acidic solution, CaP-N released calcium and phosphate ions thanks to the preferential β-tricalcium phosphate phase dissolution. Enamel remineralization was induced by CaP-N comparably to CaP-S, while CaP-N exhibited a superior dentinal tubule occlusion than CaP-S, forming mineral plugs and depositing new nanoparticles onto demineralized collagen. This behavior was attributed to its bigger particle size and increased solubility. DMA depth profiling and SEM showed an excellent interaction between the newly formed mineralized structures and the pristine tissue, particularly at the exposed collagen fibrils.

SIGNIFICANCE

CaP-N demonstrated very good remineralizing and occlusive activity in vitro, comparable to CaP-S, thus could be a promising circular economy alternative therapeutic agent for dentistry.

The star approach, a surgical approach for skin sparing mastectomy and central lumpectomies

When preservation of the nipple-areolar complex (NAC) is not possible in oncologic breast surgery, the traditional approaches are either a horizontal incision centered on the NAC resulting in visible scars and breast distortion, or a round block with risk of healing difficulties. To address these concerns, the authors propose a star approach technique for skin sparing mastectomies and lumpectomies of central breast tumors. During the oncologic surgery, the NAC is removed with four cutaneous extensions, which can be closed as a cross-shaped scar. The scarring is similar in size to the original NAC diameter and can easily be covered by the NAC reconstruction. This technique offers good exposure during surgery, a good aesthetic result with limited scarring, no breast deformity, correction of breast sagging, and high-quality healing.

Single-cell functional genomics reveals determinants of sensitivity and resistance to natural killer cells in blood cancers

Cancer cells can evade natural killer (NK) cell activity, thereby limiting anti-tumor immunity. To reveal genetic determinants of susceptibility to NK cell activity, we examined interacting NK cells and blood cancer cells using single-cell and genome-scale functional genomics screens. Interaction of NK and cancer cells induced distinct activation and type I interferon (IFN) states in both cell types depending on the cancer cell lineage and molecular phenotype, ranging from more sensitive myeloid to less sensitive B-lymphoid cancers. CRISPR screens in cancer cells uncovered genes regulating sensitivity and resistance to NK cell-mediated killing, including adhesion-related glycoproteins, protein fucosylation genes, and transcriptional regulators, in addition to confirming the importance of antigen presentation and death receptor signaling pathways. CRISPR screens with a single-cell transcriptomic readout provided insight into underlying mechanisms, including regulation of IFN-γ signaling in cancer cells and NK cell activation states. Our findings highlight the diversity of mechanisms influencing NK cell susceptibility across different cancers and provide a resource for NK cell-based therapies.

Stromal vascular fraction in the treatment of myositis

Muscle regeneration is a physiological process that converts satellite cells into mature myotubes under the influence of an inflammatory environment progressively replaced by an anti-inflammatory environment, with precise crosstalk between immune and muscular cells. If the succession of these phases is disturbed, the immune system can sometimes become auto-reactive, leading to chronic muscular inflammatory diseases, such as myositis. The triggers of these autoimmune myopathies remain mostly unknown, but the main mechanisms of pathogenesis are partially understood. They involve chronic inflammation, which could be associated with an auto-reactive immune response, and gradually with a decrease in the regenerative capacities of the muscle, leading to its degeneration, fibrosis and vascular architecture deterioration. Immunosuppressive treatments can block the first part of the process, but sometimes muscle remains weakened, or even still deteriorates, due to the exhaustion of its capacities. For patients refractory to immunosuppressive therapies, mesenchymal stem cells have shown interesting effects but their use is limited by their availability. Stromal vascular fraction, which can easily be extracted from adipose tissue, has shown good tolerance and possible therapeutic benefits in several degenerative and autoimmune diseases. However, despite the increasing use of stromal vascular fraction, the therapeutically active components within this heterogeneous cellular product are ill-defined and the mechanisms by which this therapy might be active remain insufficiently understood. We review herein the current knowledge on the mechanisms of action of stromal vascular fraction and hypothesise on how it could potentially respond to some of the unmet treatment needs of refractory myositis.

Surgical management of slightly or non-displaced corporal scaphoid fractures by retrograde percutaneous screw fixation through the anterior trapezium horn: A single-center retrospective French study of 33 patients between January 2015 and January 2019

INTRODUCTION

Percutaneous screw fixation has recently gained popularity as an alternative to conservative treatment to avoid prolonged immobilization. The placement of a screw in the central axis of the scaphoid has been shown to be biomechanically superior to its eccentricity. Still, it poses difficulties in performing percutaneous screw fixation via both palmar and dorsal approaches.

OBJECTIVE

We describe a palmar percutaneous screwing of corporal fractures of the scaphoid by a simple palmar transtrapezial approach allowing an optimal centering of the screw.

METHOD

We selected patients operated on by the same surgeon using the palmar transtrapezial approach between January 2015 and January 2019 based on the coding used for these fractures and the operative reports. In addition, pre- and postoperative data were collected from the patient's computer and paper records and by telephone contact with the patients.

RESULTS

Thirty-three patients were included. Percutaneous screw fixation of the scaphoid was performed under locoregional anesthesia in the operating room with one arm in the supine position on the arm table. No hyper-extension of the wrist was performed. The Kirchner guidewire passed through the anterior horn of the trapezium and then into the trapezium-scaphoid joint. A screw replaced it after satisfactory centering in the axis of the scaphoid. Management took place on average within 12 days after the trauma. 75.8% were A2 fractures, according to Herbert's classification. The average operating time was 16.63minutes, and in 91% of the cases, the patient was hospitalized for one day. The variation of the scapholunate angle on the preoperative profile radiographs with the angle defined by the axis of the scaphoid screw and the lunate postoperatively was on average 2.94°. One patient presented nonunion, and four showed an undersized screw with a screw overhang requiring revision surgery.

CONCLUSION

The transtrapezial approach to fixation of acute scaphoid fractures facilitates precise percutaneous screw placement in the central axis of the scaphoid. A study of long-term complications, including the degenerative impact on the scaphotrapezial joint, is needed to assess the safety of passage through the anterior horn of the trapezium.

Genome-scale functional genomics identify genes preferentially essential for multiple myeloma cells compared to other neoplasias

Clinical progress in multiple myeloma (MM), an incurable plasma cell (PC) neoplasia, has been driven by therapies that have limited applications beyond MM/PC neoplasias and do not target specific oncogenic mutations in MM. Instead, these agents target pathways critical for PC biology yet largely dispensable for malignant or normal cells of most other lineages. Here we systematically characterized the lineage-preferential molecular dependencies of MM through genome-scale clustered regularly interspaced short palindromic repeats (CRISPR) studies in 19 MM versus hundreds of non-MM lines and identified 116 genes whose disruption more significantly affects MM cell fitness compared with other malignancies. These genes, some known, others not previously linked to MM, encode transcription factors, chromatin modifiers, endoplasmic reticulum components, metabolic regulators or signaling molecules. Most of these genes are not among the top amplified, overexpressed or mutated in MM. Functional genomics approaches thus define new therapeutic targets in MM not readily identifiable by standard genomic, transcriptional or epigenetic profiling analyses.

Trends of Neutron Skins and Radii of Mirror Nuclei from First Principles

The neutron skin of atomic nuclei impacts the structure of neutron-rich nuclei, the equation of state of nucleonic matter, and the size of neutron stars. Here we predict the neutron skin of selected light- and medium-mass nuclei using coupled-cluster theory and the auxiliary field diffusion Monte Carlo method with two- and three-nucleon forces from chiral effective field theory. We find a linear correlation between the neutron skin and the isospin asymmetry in agreement with the liquid-drop model and compare with data. We also extract the linear relationship that describes the difference between neutron and proton radii of mirror nuclei and quantify the effect of charge symmetry breaking terms in the nuclear Hamiltonian. Our results for the mirror-difference charge radii and binding energies per nucleon agree with existing data.

Lenalidomide, bortezomib and dexamethasone induction therapy for the treatment of newly diagnosed multiple myeloma: a practical review

For patients with newly diagnosed multiple myeloma, survival outcomes continue to improve significantly: however, nearly all patients will relapse following induction treatment. Optimisation of induction therapy is essential to provide longer term disease control and the current standard of care for most patients incorporates an immunomodulatory agent and proteasome inhibitor, most commonly lenalidomide and bortezomib in combination with dexamethasone (RVD), with maintenance until progression. Historically there has been limited access to RVD as an induction strategy outside of the United States; fortunately, there is now increasing access worldwide. This review discusses the rationale for use of RVD as induction therapy and aims to provide guidance in prescribing this regimen in order to optimise efficacy while minimising the toxicities of treatment. We also highlight the increasing evidence for the utility of addition of a monoclonal antibody to the RVD backbone to deepen responses and potentially provide longer disease control.

[Breasts and congenital chest-wall deformities: Surgical strategy with 3D implants]

Computer-aided design and manufacturing of custom-made elastomer implants leads from a CT scan to fill in with precision, a congenital chest wall congenital deformity, both bone (pectus excavatum) and muscle (Poland Syndrome), resulting in a natural repositioning of the breasts. We report our 25 years' experience in 301 women (234 Pectus+64 Poland). Parietal correction must always be done in first intention. It is common to have to carry out a second stage in women with an additional mammaplasty especially in the presence of insufficient glandular volume or a fairly frequently associated tuberous breast.

Innervation of digital joints: an anatomical overview

INTRODUCTION

The innervation of the digital joints as well as the anatomical relationships of the articular branches is present in this anatomical work to determine the technical feasibility of a selective and efficient denervation of the digital joints.

MATERIALS AND METHODS

A study of 40 distal interphalangeal (DIP), 40 proximal interphalangeal (PIP), 50 metacarpophalangeal (MCP), 10 interphalangeal (IP) of the thumb, and 10 trapezo-metacarpophalangeal (TMC) joints was performed on ten hands. Under magnification and a proper surgical approach, we collected the course, the source origin, the number of articular nerve branches, and their caliber.

RESULTS

In total, 118 nerve branches arising from the proper palmar digital nerves were found on 10 DIP of each dissected long finger (n = 40). A total of 226 nerve branches were found on 10 PIPs of each long finger (n = 40), of which 204 branches (90.3%) had a palmar origin. Dorsal innervation was found for the ring and little finger, originating from the dorso-ulnar digital nerve. 212 branches were found on 10 MCP of long fingers (n = 40), including 87 branches of palmar origin (41.1%), 107 branches of dorsal origin (50.4%), and 18 branches of the motor branch of the ulnar nerve (8.5%). 42 articular branches directed to the TMC joint (n = 10) were found. 13 branches (31%) originated from the anterior sensory branch of the radial nerve, 13 branches (31%) originated from the lateral cutaneous nerve of the forearm, 5 branches (12%) originated from the palmar cutaneous branch of the median nerve, and 11 (26%) branches originated from the thenar branch of the median nerve. The involvement of the sensory anterior branch of the radial nerve was always present for the innervation of each TMC.

DISCUSSION AND CONCLUSION

Our research shows that finger joints receive their primary innervation from small branches of the digital nerves with the exception of the MCP joint and the TMC joint. To obtain an efficient and a selective digital denervation for articular pain relief, it is necessary to plan the best surgical approach and it is crucial to recognize the articular nervous branch localization and source.

Genome-scale screens identify factors regulating tumor cell responses to natural killer cells

To systematically define molecular features in human tumor cells that determine their degree of sensitivity to human allogeneic natural killer (NK) cells, we quantified the NK cell responsiveness of hundreds of molecularly annotated 'DNA-barcoded' solid tumor cell lines in multiplexed format and applied genome-scale CRISPR-based gene-editing screens in several solid tumor cell lines, to functionally interrogate which genes in tumor cells regulate the response to NK cells. In these orthogonal studies, NK cell-sensitive tumor cells tend to exhibit 'mesenchymal-like' transcriptional programs; high transcriptional signature for chromatin remodeling complexes; high levels of B7-H6 (NCR3LG1); and low levels of HLA-E/antigen presentation genes. Importantly, transcriptional signatures of NK cell-sensitive tumor cells correlate with immune checkpoint inhibitor (ICI) resistance in clinical samples. This study provides a comprehensive map of mechanisms regulating tumor cell responses to NK cells, with implications for future biomarker-driven applications of NK cell immunotherapies.

Abstract PO041: Landscape of molecular events regulating tumor cell responses to natural killer cells

Natural killer (NK) cells exhibit potent activity in pre-clinical models of diverse hematologic malignancies and solid tumors and infusion of high numbers of NK cells, either autologous or allogeneic, after their ex vivo expansion and activation, has been feasible and safe in clinical studies. To systematically define molecular features in human tumor cells which determine their degree of sensitivity to human allogeneic NK cells, we quantified the NK cell responsiveness of hundreds of molecularly-annotated “DNA-barcoded” solid tumor cell lines in multiplexed format (PRISM; Profiling Relative Inhibition Simultaneously in Mixtures approach), correlating cytotoxicity scores for each cell line with the CCLE transcriptional data (RNA-seq), to reveal genes that are associated with resistance or sensitivity to NK cells. In addition, we applied genome-scale CRISPR-based gene editing screens in several solid tumor cell lines to interrogate, at a functional level, which genes regulate tumor cell response to NK cells. Based on these orthogonal studies, NK sensitive tumor cells tend to exhibit high levels of the NK cell-activating ligand B7-H6 (NCR3LG1); low levels of the inhibitory ligand HLA-E; microsatellite instability (MSI) status; high transcriptional signature for chromatin remodeling complexes and low antigen presentation machinery genes. Treatment with an HDAC inhibitor reduced the sensitivity of SW620 colon cancer cells, increased antigen presentation machinery, including HLA-E, and reduced B7-H6. Importantly, we observe that transcriptional signatures of NK cell-sensitive tumor cells correlate with immune checkpoint inhibitor resistance in clinical samples. Strikingly, comprehensive analysis of the CCLE transcriptional signatures revealed that cell lines with mesenchymal-like program tend to be more sensitive to NK cells treatment, compared with cell lines of epithelial-like program. Indeed, mesenchymal tumors tend to have lower expression of antigen presentation machinery in both CCLE and TCGA, suggesting a link between these two machieneries. This study provides a comprehensive map of mechanisms regulating tumor cell responses to NK cells, with implications for future biomarker-driven applications of NK cell immunotherapies.

Citation Format: Michal Sheffer, Emily Lowry, Nicky Beelen, Minasri Borah, Suha Naffar-Abu Amara, Chris C. Mader, Jennifer Roth, Aviad Tsherniak, Olga Dashevsky, Sara Gandolfi, Samantha Bender, Jordan Bryan, Cong Zhu, Li Wang, Ricardo De-Matos Simoes, Channing Yu, Yiguo Hu, Olli Dufva, Marios Giannakis, Todd Golub, Rizwan Romee, Satu Mustjoki, Aedin C. Culhane, Lotte Wieten, Constantine S. Mitsiades. Landscape of molecular events regulating tumor cell responses to natural killer cells [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2020 Oct 19-20. Philadelphia (PA): AACR; Cancer Immunol Res 2021;9(2 Suppl):Abstract nr PO041.

Functional Genomics Identify Distinct and Overlapping Genes Mediating Resistance to Different Classes of Heterobifunctional Degraders of Oncoproteins

Heterobifunctional proteolysis-targeting chimeric compounds leverage the activity of E3 ligases to induce degradation of target oncoproteins and exhibit potent preclinical antitumor activity. To dissect the mechanisms regulating tumor cell sensitivity to different classes of pharmacological "degraders" of oncoproteins, we performed genome-scale CRISPR-Cas9-based gene editing studies. We observed that myeloma cell resistance to degraders of different targets (BET bromodomain proteins, CDK9) and operating through CRBN (degronimids) or VHL is primarily mediated by prevention of, rather than adaptation to, breakdown of the target oncoprotein; and this involves loss of function of the cognate E3 ligase or interactors/regulators of the respective cullin-RING ligase (CRL) complex. The substantial gene-level differences for resistance mechanisms to CRBN- versus VHL-based degraders explains mechanistically the lack of cross-resistance with sequential administration of these two degrader classes. Development of degraders leveraging more diverse E3 ligases/CRLs may facilitate sequential/alternating versus combined uses of these agents toward potentially delaying or preventing resistance.

Nostril Surgery: Indications, Surgical Procedures and Outcomes-A Systematic Review of Published Cases

INTRODUCTION

To achieve adequate nasal proportions, nostril surgery can be a complementary technique useful in facial surgery. To help surgeons with the decision to realize nostril surgery, we conducted a systematic review to summarize reported cases on surgical procedures with a specific interest on indications, surgical procedures and postoperative outcomes. A therapeutic algorithm is also proposed.

METHOD

We carried out this review in accordance with the PRISMA criteria. Twenty-two eligible studies were identified using Medical databases, including 1599 patients. A qualitative and quantitative analysis was carried out.

DISCUSSION

Excision techniques were realized on 728 patients (45.5%), followed by cinching sutures on 642 patients (40%) and combined techniques: excision techniques with flap advancement techniques in 189 cases (12%), excision techniques with flap advancement techniques and cinching suture in 40 patients (2.5%). When excessive alar flaring was present, alar wedge resection was preferred in the 92% of followed by alar and sill resection. Cinching sutures were realized when excessive alar flaring was associated with a vertical alar axis, in cases of wide alar base, of associated orthognathic surgery. When excessive alar flaring was associated with wide alar bases, indications changed basing on the associated deformities. In 795 patients, nostril surgery was conducted simultaneously with rhinoplasty.

CONCLUSION

Nostril surgery through excision techniques, cinching sutures or flaps advancement techniques, reveals good outcomes and can be complementary to rhinoplasty or orthognathic surgery. Through this systematic review, we tried to orient surgeons to find the best treatment for nostril base surgery.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Current antibody-based therapies for the treatment of multiple myeloma

Despite continued and considerable progress following the introduction of proteasome inhibitors and immunomodulatory agents, multiple myeloma (MM) remains an incurable disease, and new therapeutic strategies are urgently needed. Monoclonal antibodies represent a well-established targeted approach to the treatment of MM, with selective killing properties and limited off-target toxicity. Since their approval, the anti-CD38 agent daratumumab, the anti-SLAMF7 agent elotuzumab, and most recently the anti-CD38 agent isatuximab have led to pivotal improvements in the treatment of double-refractory MM; currently, they are on their way to becoming integral parts in the up-front care of patients who have newly diagnosed MM, with daratumumab already approved in this setting. Several other antibody-based strategies are undergoing clinical assessment in MM. Although the investigation of checkpoint inhibitors in MM has been halted, bispecific T-cell engagers and especially antibody-drug conjugates demonstrate encouraging efficacy and manageable toxicity in triple class-refractory MM. The accelerated approval of belantamab mafodotin represents an important milestone in antibody development; its ability to target B-cell maturation antigen (BCMA) in advanced disease is now established. Here, we present an overview of the currently available monoclonal antibody treatments in MM and discuss the clinical value, significant potential, and possible limitations of these immunotherapeutic approaches to driving deeper responses and achieving longer overall survival among patients with a challenging disease.

Lower limb perforator flaps: Current concept

Following a long period dominated by random fasciocutaneous flaps or muscle flaps, solutions to cover the lower limb have been largely diversified by the advent of so-called "perforator" flaps. Extended knowledge of vascular anatomy has propagated the development of this innovative procedure, in the objective of reducing morbidity. The existence of close to 400 perforator vessels in the body makes it possible to offer new flap perspectives for many defects, which were sometimes previously impossible to manage before except by free flap. For us, perforator flaps have become the current first-line solutions for small to medium size loss of substances. Understanding of vascular physiology and surgical experience are essential in choosing indications, detecting perforators, and modeling flaps to be optimally positioned in the reconstructive decisional algorithm. New skills are needed to master this type of reconstruction and limit failures, which implies a learning curve not only for flap design, perforator detection and surgical procedure, but also for monitoring and management of complications. In this manuscript, we outline the concepts and principles of the majority of the pedicled perforator flaps available for coverage of the lower limb, based on experience of more than 400 perforator flaps suitable for this localization.

Finger joint denervation in hand osteoarthritis: Indications, surgical techniques and outcomes. A systematic review of published cases

In cases of osteoarthritis with preserved motion, joint denervation can be an effective alternative to arthroplasty or arthrodesis to reduce joint-related pain. Although denervation is a standardized procedure for wrist osteoarthritis, it is used sparingly for finger joints. We conducted a systematic review to summarize reported cases of finger joint denervation in hand osteoarthritis with a specific focus on surgical procedures and postoperative outcomes. PubMed, Cochrane and Science Direct databases were searched from 1998 to 2019 and 13 relevant articles were selected. Three hundred and twenty-five denervations were conducted on 291 patients. Distal interphalangeal (DIP) joint denervation was performed through a dorsal approach; 83% of patients were satisfied with the surgery and complications occurred in 58%. Proximal interphalangeal (PIP) joint denervation was performed through a palmar approach; 90% of patients were satisfied with the surgery; complications were observed in 14%. Good results were observed in 95% of patients who underwent metacarpophalangeal (MCP) joint denervation; complications were observed in 26%; denervation was carried out with dorsal and palmar approaches in all cases. Denervation of the trapeziometacarpal (TMC) joint was achieved through the Wagner approach (61%), multiple incisions (26%), or dorsal approach (13%); satisfaction rate was 91%, with a 6% complication rate. Finger joint denervation in hand osteoarthritis is a simple and effective procedure, providing satisfactory pain relief. Good results are reported in all studies, especially for PIP and TMC joint denervation. Further investigations should be conducted on DIP and MCP joint denervation.

Vascularization of the superficial circumflex iliac perforator flap (SCIP flap): an anatomical study

INTRODUCTION

The superficial circumflex iliac artery perforator flap (SCIP) has gained widespread popularity as local or free flap to cover soft tissue defects. However, there are numerous anatomical variations in terms of size, location and reliability of its perforators This cadaveric study aimed to focus on the anatomical bases of this flap.

MATERIALS AND METHODS

A bilateral dissection of seven cadavers was performed to harvest 14 flaps. Superficial circumflex iliac artery parameters, number, length and diameters of perforators were measured. Correspondent perforasomes were highlighted through semi-selective injections.

RESULTS

The major perforator of the superficial branch had a mean caliber of 2.0 mm, and a mean length of 1.8 mm. The major perforator of the deep branch had a mean caliber of 2.1 mm and a mean length of 1.43 mm. The mean area of the superficial pattern perforasome was 178.6 cm² and the mean measured surface of the deep pattern perforasome was 156.2 cm². The descending branches of the deep branch anastomosing with the ascending branch of the lateral circumflex femoral artery were found in three cases.

CONCLUSION

Several anatomical variations were observed in this anatomical study, but major perforators supplying large perforasomes were always found.

The power of proteasome inhibition in multiple myeloma

INTRODUCTION

Proteasome inhibitors (PIs) are therapeutic backbones of multiple myeloma treatment, with PI-based therapies being standards of care throughout the treatment algorithm. Proteasome inhibition affects multiple critical signaling pathways in myeloma cells and interacts synergistically with mechanisms of action of other conventional and novel agents, resulting in substantial anti-myeloma activity and at least additive effects. Areas covered: This review summarizes the biologic effects of proteasome inhibition in myeloma and provides an overview of the importance of proteasome inhibition to the current treatment algorithm. It reviews key clinical data on three PIs, specifically bortezomib, carfilzomib, and ixazomib; assesses ongoing phase 3 trials with these agents; and looks ahead to the increasingly broad role of both approved PIs and PIs under investigation in the frontline and relapsed settings. Expert commentary: Progress to date with PIs in multiple myeloma has been impressive, but there remain unmet needs and challenges, as well as increasing opportunities to optimize the use of these agents. Understanding discrepancies between PIs in terms of efficacy and safety profile is a key goal of ongoing research, along with proteomics-based efforts to identify potential biomarkers of sensitivity and resistance, thereby enabling increasingly personalized treatment approaches in the future.

The evolving role of transplantation in multiple myeloma: the need for a heterogeneous approach to a heterogeneous disease

Autologous stem cell transplant (ASCT) is an established frontline standard of care for the younger, fitter patients with newly diagnosed multiple myeloma (NDMM) who are eligible for the procedure, and has contributed to improved overall survival. In the current era of novel therapies, the treatment landscape and prognosis have changed. The outstanding efficacy seen with regimens based on novel agents has led to a questioning of the frontline treatment paradigm with respect to ASCT. A key current question is whether to use transplant early or to collect stem cells early but save ASCT for salvage therapy. In this review, we evaluate the clinical data for each approach as well as the arguments in favor of early or delayed ASCT. We also consider the clinical/clonal heterogeneity of myeloma and review the evidence regarding which patient subgroups may benefit most from each approach. We summarize current treatment guidelines for transplant-eligible patients with NDMM and review the evolving role of minimal residual disease evaluation and its potential effect on the debate over early vs delayed ASCT. We conclude that frontline ASCT remains a standard of care for a substantial proportion of patients; however, delayed/salvage ASCT is increasingly being used in the context of highly active frontline regimens based on novel agents and the ongoing personalization of myeloma treatment.

Abstract 2834: Genomewide CRISPR studies of sequential treatment with CRBN-based degronimids: Insights into the molecular evolution of treatment resistance in myeloma and beyond

Degronimids are bifunctional agents in which a thalidomide-like moiety brings the E3 ligase CRBN close to proteins which bind to the second functionality of these compounds, leading to ubiquitination and proteasomal degradation of these latter proteins. Our groups and others have examined BET bromodomain (BRD)-containing proteins BRD2,3, and 4 (dBET6) or CDK9 (ZZ1-33, referred to herein as dCDK9). We documented that both dBET and dCDK9 compounds trigger rapid induction of multiple myeloma (MM) cell death in vitro. To dissect the mechanisms regulating the response vs. resistance of MM cells to degronimids, we performed genome-wide CRISPR/Cas9-based gene editing screens using lentiviral particles of a pooled sgRNA library (Brunello; ~70,000 sgRNAs against ~20,000 genes; 4 sgRNAs/gene; plus additional non-targeting control sgRNAs). In screens with both CRBN-mediated "degraders", we observed consistent and pronounced enrichment of sgRNAs for CRBN itself, and also other upstream components or regulators of the complex that regulates CRBN function (e.g. DDB1, CAND1), E2 ubiquitin conjugating enzymes (e.g. UBE2G1) and multiple members of the signalosome complex (COPS7A, COPS7B, GPS1, et.c.). These results indicate that a primary mechanism of degronimid-resistance relates not to adaptation to the degradation of their respective targets, but to via loss of function (LOF) of CRBN or its positive regulators, to prevent degradation of the degronimid target(s). Also, we observed that dCDK9-resistant MM.1S cells which established from our CRISPR screen, upon more extensive treatment with either dCDK9 or dBET led to further enrichment of the CRBN sgRNA-containing tumor cells, with significant decrease in the fraction of the population with sgRNAs for other hits. These observations imply that LOF for positive regulators of CRBN activity may provide protection in short-term, but the role of several of these genes for MM cell proliferation/survival may limit the longer-term fitness of these populations, allowing cells with CRBN LOF to outcompete other potential forms of resistance. This finding may also indirectly explain why clinical resistance to thalidomide or its derivatives, CRBN-mediated "degraders of IKZF1/IKF3, are reported to involve LOF of CRBN, rather than most of its regulators of CRBN. Our CRISPR studies document the concordance in mechanisms of resistance to "degronimids" targeting different proteins for degradation; and how time-course analyses in these CRISPR screens can reveal the dynamics between sub-populations of tumor cells harboring sgRNA-mediated LOF for different candidate genes.

Citation Format: Ryosuke Shirasaki, Sara Gandolfi, Ricardo De Matos Simoes, Geoffrey Matthews, Sondra Downey, Olga Dashevsky, Tang Huihui, Michal Sheffer, Eugen Dhimolea, Megan Bariteau, Jeffrey Sorrel, Nick Kwiatkowski, Thinghu Zhang, Nathanael Gray, Constantine Mitsiades. Genomewide CRISPR studies of sequential treatment with CRBN-based degronimids: Insights into the molecular evolution of treatment resistance in myeloma and beyond [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2834.

The proteasome and proteasome inhibitors in multiple myeloma

Proteasome inhibitors are one of the most important classes of agents to have emerged for the treatment of multiple myeloma in the past two decades, and now form one of the backbones of treatment. Three agents in this class have been approved by the United States Food and Drug Administration-the first-in-class compound bortezomib, the second-generation agent carfilzomib, and the first oral proteasome inhibitor, ixazomib. The success of this class of agents is due to the exquisite sensitivity of myeloma cells to the inhibition of the 26S proteasome, which plays a critical role in the pathogenesis and proliferation of the disease. Proteasome inhibition results in multiple downstream effects, including the inhibition of NF-κB signaling, the accumulation of misfolded and unfolded proteins, resulting in endoplasmic reticulum stress and leading to the unfolded protein response, the downregulation of growth factor receptors, suppression of adhesion molecule expression, and inhibition of angiogenesis; resistance to proteasome inhibition may arise through cellular responses mediating these downstream effects. These multiple biologic consequences of proteasome inhibition result in synergistic or additive activity with other chemotherapeutic and targeted agents for myeloma, and proteasome inhibitor-based combination regimens have become established as a cornerstone of therapy throughout the myeloma treatment algorithm, incorporating agents from the other key classes of antimyeloma agents, including the immunomodulatory drugs, monoclonal antibodies, and histone deacetylase inhibitors. This review gives an overview of the critical role of the proteasome in myeloma and the characteristics of the different proteasome inhibitors and provides a comprehensive summary of key clinical efficacy and safety data with the currently approved proteasome inhibitors.

Properties of Nuclei up to A=16 using Local Chiral Interactions

We report accurate quantum Monte Carlo calculations of nuclei up to A=16 based on local chiral two- and three-nucleon interactions up to next-to-next-to-leading order. We examine the theoretical uncertainties associated with the chiral expansion and the cutoff in the theory, as well as the associated operator choices in the three-nucleon interactions. While in light nuclei the cutoff variation and systematic uncertainties are rather small, in ^{16}O these can be significant for large coordinate-space cutoffs. Overall, we show that chiral interactions constructed to reproduce properties of very light systems and nucleon-nucleon scattering give an excellent description of binding energies, charge radii, and form factors for all these nuclei, including open-shell systems in A=6 and 12.

Ground-State Properties of Unitary Bosons: From Clusters to Matter

The properties of cold Bose gases at unitarity have been extensively investigated in the last few years both theoretically and experimentally. In this Letter we use a family of interactions tuned to two-body unitarity and very weak three-body binding to demonstrate the universal properties of both clusters and matter. We determine the universal properties of finite clusters up to 60 particles and, for the first time, explicitly demonstrate the saturation of energy and density with particle number and compare with bulk properties. At saturation in the bulk we determine the energy, density, two- and three-body contacts, and the condensate fraction. We find that uniform matter is more bound than three-body clusters by nearly 2 orders of magnitude, the two-body contact is very large in absolute terms, and yet the condensate fraction is also very large, greater than 90%. Equilibrium properties of these systems may be experimentally accessible through rapid quenching of weakly interacting boson superfluids.

Abstract LB-118: Characterization of lineage vs. context-dependent essential genes in multiple myeloma using CRISPR-Cas9 genome editing

Multiple Myeloma (MM) remains incurable in part due to an incomplete understanding of the genes critically responsible for MM cell survival and proliferation. We reasoned that CRISPR/Cas9-based functional genomics could identify genes essential for survival or proliferation of MM cells and define candidate therapeutic targets. We transduced Cas9-expressing RPMI-8226 and MM.1S cells with lentiviral genome-scale GeCKO pooled libraries of sgRNAs. After culture of these cell lines for 2-12 weeks without treatment we identified, based on next generation sequencing, genes with significantly depleted sgRNAs (4-6 sgRNAs/gene, >2-fold average depletion, FDR<0.05, using MAGECK algorithm) in Cas9+ cells compared to initial sgRNA plasmid pools, baseline cultures, or isogenic parental Cas9-negative cells. These results were confirmed for each cell line with a 2nd independent genome-wide analysis and with a focused sgRNA library containing a subset of candidates defined by the genome-wide analyses. We compared these results with data from our in-house or publicly available CRISPR/Cas9 gene editing studies, involving a total of 175 cell lines from other hematologic malignancies and solid tumors. We next integrated our functional data for these genes with their: a) Achilles Heel shRNA data; b) gene expression (RNASeq); c) gene copy number status; d) mutation status; e) proximity to superenhancers; and f) altered expression in MM cells co-cultured with bone marrow stromal cells. We applied a series of statistical tests (e.g. Wilcoxon rank) to identify genes with significantly higher rank in sgRNA or shRNA depletion in MM vs. non-MM lines and stringently identified 50+ candidate genes with preferential dependency in MM. Prominent examples included: transcription factors (e.g. IRF4, CCND2, MAF, NFKB1, NFKB2, RELA, RELB); other NF-κB-related genes (e.g. IKBKB); PIM2; regulators of protein homeostasis; and several other known or biologically plausible dependencies which are under further evaluation. In >90% of MM patients, the candidate MM-preferential essential genes are not mutated. Some of these genes are overexpressed in MM vs. non-MM cell lines (CCLE dataset) or patient-derived samples (Broad/MMRF vs. TCGA datasets); induced by BMSC co-culture; proximal to superenhancers; or correlating with clinical outcome. However, these molecular results were not sufficient, collectively or individually, to identify this cohort of MM-preferential essential genes independently of the CRISPR functional data. Targeting lineage-specific dependencies (e.g. ER or AR in breast or prostate Ca, respectively) has provided major clinical benefit in some tumors; while context-specific dependencies are a cornerstone of molecularly-guided individualized treatments. Therefore, by identifying lineage- and context-dependent essential genes for MM, our functional genomic studies in molecularly annotated MM vs. non-MM cell lines provide an attractive framework towards designing novel therapies for MM.

Citation Format: Geoffrey M. Matthews, Ricardo de Matos Simoes, Yiguo Hu, Michal Sheffer, Olga Dashevsky, Eugen Dhimolea, Paul J. Hengeveld, Brian J. Glassner, Sara Gandolfi, Megan A. Bariteau, Quinlan Sievers, Benjamin L. Ebert, Franciska Vazquez, Aedin Culhane, Constantine S. Mitsiades. Characterization of lineage vs. context-dependent essential genes in multiple myeloma using CRISPR-Cas9 genome editing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-118. doi:10.1158/1538-7445.AM2017-LB-118

Electromagnetic Response of ^{12}C: A First-Principles Calculation

The longitudinal and transverse electromagnetic response functions of ^{12}C are computed in a "first-principles" Green's function Monte Carlo calculation, based on realistic two- and three-nucleon interactions and associated one- and two-body currents. We find excellent agreement between theory and experiment and, in particular, no evidence for the quenching of the measured versus calculated longitudinal response. This is further corroborated by a reanalysis of the Coulomb sum rule, in which the contributions from the low-lying J^{π}=2^{+}, 0_{2}^{+} (Hoyle), and 4^{+} states in ^{12}C are accounted for explicitly in evaluating the total inelastic strength.

NF-κB dysregulation in multiple myeloma

The nuclear factor-κB (NF-κB) transcription factor family plays critical roles in the pathophysiology of hematologic neoplasias, including multiple myeloma. The current review examines the roles that this transcription factor system plays in multiple myeloma cells and the nonmalignant accessory cells of the local microenvironment; as well as the evidence indicating that a large proportion of myeloma patients harbor genomic lesions which perturb diverse genes regulating the activity of NF-κB. This article also discusses the therapeutic targeting of the NF-κB pathway using proteasome inhibitors, a pharmacological class that has become a cornerstone in the therapeutic management of myeloma; and reviews some of the future challenges and opportunities for NF-κB-related research in myeloma.

Chiral Three-Nucleon Interactions in Light Nuclei, Neutron-α Scattering, and Neutron Matter

We present quantum Monte Carlo calculations of light nuclei, neutron-α scattering, and neutron matter using local two- and three-nucleon (3N) interactions derived from chiral effective field theory up to next-to-next-to-leading order (N(2)LO). The two undetermined 3N low-energy couplings are fit to the (4)He binding energy and, for the first time, to the spin-orbit splitting in the neutron-α P-wave phase shifts. Furthermore, we investigate different choices of local 3N-operator structures and find that chiral interactions at N(2)LO are able to simultaneously reproduce the properties of A=3,4,5 systems and of neutron matter, in contrast to commonly used phenomenological 3N interactions.