Apoptotic cell fragments locally activate tingible body macrophages in the germinal center.

Germinal centers (GCs) that form within lymphoid follicles during antibody responses are sites of massive cell death. Tingible body macrophages (TBMs) are tasked with apoptotic cell clearance to prevent secondary necrosis and autoimmune activation by intracellular self antigens. We show by multiple redundant and complementary methods that TBMs derive from a lymph node-resident, CD169-lineage, CSF1R-blockade-resistant precursor that is prepositioned in the follicle. Non-migratory TBMs use cytoplasmic processes to chase and capture migrating dead cell fragments using a "lazy" search strategy. Follicular macrophages activated by the presence of nearby apoptotic cells can mature into TBMs in the absence of GCs. Single-cell transcriptomics identified a TBM cell cluster in immunized lymph nodes which upregulated genes involved in apoptotic cell clearance. Thus, apoptotic B cells in early GCs trigger activation and maturation of follicular macrophages into classical TBMs to clear apoptotic debris and prevent antibody-mediated autoimmune diseases.

Lymph Node Mesenchymal and Endothelial Stromal Cells Cooperate via the RANK-RANKL Cytokine Axis to Shape the Sinusoidal Macrophage Niche.

Tissue-resident macrophages are receptive to specific signals concentrated in cellular niches that direct their cell differentiation and maintenance genetic programs. Here, we found that deficiency of the cytokine RANKL in lymphoid tissue organizers and marginal reticular stromal cells of lymph nodes resulted in the loss of the CD169+ sinusoidal macrophages (SMs) comprising the subcapsular and the medullary subtypes. Subcapsular SM differentiation was impaired in mice with targeted RANK deficiency in SMs. Temporally controlled RANK removal in lymphatic endothelial cells (LECs) revealed that lymphatic RANK activation during embryogenesis and shortly after birth was required for the differentiation of both SM subtypes. Moreover, RANK expression by LECs was necessary for SM restoration after inflammation-induced cell loss. Thus, cooperation between mesenchymal cells and LECs shapes a niche environment that supports SM differentiation and reconstitution after inflammation.

CD169+ macrophages in lymph node and spleen critically depend on dual RANK and LTbetaR signaling.

CD169+ macrophages reside in lymph node (LN) and spleen and play an important role in the immune defense against pathogens. As resident macrophages, they are responsive to environmental cues to shape their tissue-specific identity. We have previously shown that LN CD169+ macrophages require RANKL for formation of their niche and their differentiation. Here, we demonstrate that they are also dependent on direct lymphotoxin beta (LTß) receptor (R) signaling. In the absence or the reduced expression of either RANK or LTßR, their differentiation is perturbed, generating myeloid cells expressing SIGN-R1 in LNs. Conditions of combined haploinsufficiencies of RANK and LTßR revealed that both receptors contribute equally to LN CD169+ macrophage differentiation. In the spleen, the Cd169-directed ablation of either receptor results in a selective loss of marginal metallophilic macrophages (MMMs). Using a RANKL reporter mouse, we identify splenic marginal zone stromal cells as a source of RANKL and demonstrate that it participates in MMM differentiation. The loss of MMMs had no effect on the splenic B cell compartments but compromised viral capture and the expansion of virus-specific CD8+ T cells. Taken together, the data provide evidence that CD169+ macrophage differentiation in LN and spleen requires dual signals from LTßR and RANK with implications for the immune response.

DC-SIGN(+) Macrophages Control the Induction of Transplantation Tolerance.

Tissue effector cells of the monocyte lineage can differentiate into different cell types with specific cell function depending on their environment. The phenotype, developmental requirements, and functional mechanisms of immune protective macrophages that mediate the induction of transplantation tolerance remain elusive. Here, we demonstrate that costimulatory blockade favored accumulation of DC-SIGN-expressing macrophages that inhibited CD8(+) T cell immunity and promoted CD4(+)Foxp3(+) Treg cell expansion in numbers. Mechanistically, that simultaneous DC-SIGN engagement by fucosylated ligands and TLR4 signaling was required for production of immunoregulatory IL-10 associated with prolonged allograft survival. Deletion of DC-SIGN-expressing macrophages in vivo, interfering with their CSF1-dependent development, or preventing the DC-SIGN signaling pathway abrogated tolerance. Together, the results provide new insights into the tolerogenic effects of costimulatory blockade and identify DC-SIGN(+) suppressive macrophages as crucial mediators of immunological tolerance with the concomitant therapeutic implications in the clinic.

Is Proximal Triangular Fixation Better than the Conventional Method in Adult Spinal Deformity Surgery?

In adult spinal deformity (ASD) surgery, one of the key factors working to prevent proximal junctional kyphosis is the proximal anchor. The aim of this study was to compare clinical and radiographic outcomes of triangular fixation with conventional fixation as proximal anchoring techniques in ASD surgery. We retrospectively evaluated 54 patients who underwent corrective spinal fusion for ASD. Fourteen patients underwent proximal triangular fixation (Group T; average 74.6 years), and 40 patients underwent the conventional method (Group C; average 70.5 years). Clinical and radiographic outcomes were assessed using visual analogue scale (VAS) values for back pain and the Oswestry disability index (ODI). Radiographic evaluation was also collected preoperatively and postoperatively. Surgical times and intraoperative blood loss of the two groups were not significantly different (493 vs 490 min, 1,260 vs 1,173 mL). Clinical outcomes such as VAS and ODI were comparable in the two groups. Proximal junctional kyphosis in group T was slightly lower than that of group C (28.5% vs 47.5%, p=0.491). However, based on radiology, proximal screw pullout occurred significantly less frequently in the triangular fixation group than the conventional group (0.0% vs 22.5%, p=0.049). Clinical outcomes in the two groups were not significantly different.

Retrospective Cohort Study of Early versus Delayed Ballon Kyphoplasty Intervention for Osteoporotic Vertebral Fracture Treatment.

Objectives: To investigate the outcomes of early balloon kyphoplasty (BKP) intervention compared with late intervention for osteoporotic vertebral fracture (OVF). Background: Osteoporotic vertebral fracture can lead to kyphotic deformity, severe back pain, depression, and disturbances in activities of daily living (ADL). Balloon kyphoplasty has been widely utilized to treat symptomatic OVFs and has proven to be a very effective surgical option for this condition. Furthermore, BKP is relatively a safe and effective method due to its reduced acrylic cement leakage and greater kyphosis correction. Materials and Methods: A retrospective cohort study was conducted at our hospital for patients who underwent BKP for osteoporotic vertebral fractures in the time frame between January 2020 and December 2022. Ninety-nine patients were included in this study, and they were classified into two groups: in total, 36 patients underwent early BKP intervention (EI) at <4 weeks, and 63 patients underwent late BKP intervention (LI) at ≥4 weeks. We performed a clinical, radiological and statistical comparative evaluation for the both groups with a mean follow-up of one year. Results: Adjacent segmental fractures were more frequently observed in the LI group compared to the EI group (33.3% vs. 13.9%, p = 0.034). There was a significant improvement in postoperative vertebral angles in both groups (p = 0.036). The cement volume injected was 7.42 mL in the EI, compared with 6.3 mL in the LI (p = 0.007). The mean surgery time was shorter in the EI, at 30.2 min, compared with 37.1 min for the LI, presenting a significant difference (p = 0.0004). There was no statistical difference in the pain visual analog scale (VAS) between the two groups (p = 0.711), and there was no statistical difference in cement leakage (p = 0.192). Conclusions/Level of Evidence: Early BKP for OVF treatment may achieve better outcomes and fewer adjacent segmental fractures than delayed intervention.

A Novel Technique for Basilar Invagination Treatment in a Patient with Klippel-Feil Syndrome: A Clinical Example and Brief Literature Review.

Objectives and Background: To present a novel technique of treatment for a patient with basilar invagination. Basilar invagination (BI) is a congenital condition that can compress the cervicomedullary junction, leading to neurological deficits. Severe cases require surgical intervention, but there is debate over the choice of approach. The anterior approach allows direct decompression but carries high complication rates, while the posterior approach provides indirect decompression and offers good stability with fewer complications. Materials and Methods: A 15-year-old boy with severe myelopathy presented to our hospital with neck pain, bilateral upper limb muscle weakness, and hand numbness persisting for 4 years. Additionally, he experienced increased numbness and gait disturbance three months before his visit. On examination, he exhibited hyperreflexia in both upper and lower limbs, muscle weakness in the bilateral upper limbs (MMT 4), bilateral hypoesthesia below the elbow and in both legs, mild urinary and bowel incontinence, and a spastic gait. Radiographs revealed severe basilar invagination (BI). Preoperative images showed severe BI and that the spinal cord was severely compressed with odontoid process. Results: The patient underwent posterior surgery with the C-arm free technique. All screws including occipital screws were inserted into the adequate position under navigation guidance. Reduction was achieved with skull rotation and distraction. A follow-up at one year showed the following results: Manual muscle testing results and sensory function tests showed almost full recovery, with bilateral arm recovery (MMT 5) and smooth walking. The cervical Japanese Orthopedic Association score of the patient improved from 9/17 to 16/17. Postoperative images showed excellent spinal cord decompression, and no major or severe complications had occurred. Conclusions: Basilar invagination alongside Klippel-Feil syndrome represents a relatively uncommon condition. Utilizing a posterior approach for treating reducible BI with a C-arm-free technique proved to be a safe method in addressing severe myelopathy. This novel navigation technique yields excellent outcomes for patients with BI.

Identification of small compounds that inhibit multiple myeloma proliferation by targeting c-Maf transcriptional activity.

Multiple myeloma displays the clonal B cell expansion and the overproduction of monoclonal immunoglobulins. Genetic translocations at 14q32, particularly with partners like 16q23, lead to the dysregulation of oncogene expression, including the significant enhancement of c-Maf. This aberrant expression of c-Maf has prompted research into strategies for targeting this transcription factor as a potential therapeutic avenue for multiple myeloma treatment. In this study, we introduce a screening pipeline to test small compounds for their ability to inhibit c-Maf. Using a luciferase indicator driven by the Ccl8 gene promoter, we identified two small compounds that inhibit transcriptional activity of c-Maf. These molecules impede the proliferation of c-Maf-expressing myeloma cells, and repress the expression of c-Maf target genes such as ITGB7 and CCR1. Importantly, these molecules target c-Maf-expressing multiple myeloma cells, but not c-Maf-negative myeloma cells, showing potential for tailoring therapeutic intervention. In conclusion, our screening pipeline is effective to explore leads for a novel c-Maf inhibitor for multiple myeloma therapy.

A high-sensitivity ELISA for detection of human FGF18 in culture supernatants from tumor cell lines.

Fibroblast growth factor 18 (FGF18) is elevated in several human cancers, such as gastrointestinal and ovarian cancers, and stimulates the proliferation of tumor cells. This suggests that FGF18 may be a promising candidate biomarker in cancer patients. However, the lack of a high-sensitivity enzyme-linked immunosorbent assay (ELISA) does not permit testing of this possibility. In this study, we generated monoclonal antibodies against human FGF18 and developed a high-sensitivity ELISA to measure human FGF18 at concentrations as low as 10 pg/mL. Of the eight tumor cell lines investigated, we detected human FGF18 in culture supernatants from four tumor cell lines, including HeLa, OVCAR-3, BxPC-3, and SW620 cells, albeit the production levels were relatively low in the latter two cell lines. Moreover, the in-house ELISA could detect murine FGF18 in sera from mice overexpressing murine Fgf18 in hepatocytes, although the sensitivity in detecting murine FGF18 was relatively low. This FGF18 ELISA could be a valuable tool to validate FGF18 as a potential biomarker for cancer patients and to test the contribution of FGF18 for various disease models invivo and in vitro.

Enforced viral replication activates adaptive immunity and is essential for the control of a cytopathic virus.

The innate immune system limits viral replication via type I interferon and also induces the presentation of viral antigens to cells of the adaptive immune response. Using infection of mice with vesicular stomatitis virus, we analyzed how the innate immune system inhibits viral propagation but still allows the presentation of antigen to cells of the adaptive immune response. We found that expression of the gene encoding the inhibitory protein Usp18 in metallophilic macrophages led to lower type I interferon responsiveness, thereby allowing locally restricted replication of virus. This was essential for the induction of adaptive antiviral immune responses and, therefore, for preventing the fatal outcome of infection. In conclusion, we found that enforced viral replication in marginal zone macrophages was an immunological mechanism that ensured the production of sufficient antigen for effective activation of the adaptive immune response.

Dectin-2 is a direct receptor for mannose-capped lipoarabinomannan of mycobacteria.

Mycobacteria possess various immunomodulatory molecules on the cell wall. Mannose-capped lipoarabinomannan (Man-LAM), a major lipoglycan of Mycobacterium tuberculosis, has long been known to have both inhibitory and stimulatory effects on host immunity. However, the direct Man-LAM receptor that explains its pleiotropic activities has not been clearly identified. Here, we report that a C-type lectin receptor Dectin-2 (gene symbol Clec4n) is a direct receptor for Man-LAM. Man-LAM activated bone-marrow-derived dendritic cells (BMDCs) to produce pro- and anti-inflammatory cytokines, whereas it was completely abrogated in Clec4n(-/-) BMDCs. Man-LAM promoted antigen-specific T cell responses through Dectin-2 on DCs. Furthermore, Man-LAM induced experimental autoimmune encephalitis (EAE) as an adjuvant in mice, whereas Clec4n(-/-) mice were resistant. Upon mycobacterial infection, Clec4n(-/-) mice showed augmented lung pathology. These results demonstrate that Dectin-2 contributes to host immunity against mycobacterial infection through the recognition of Man-LAM.

The clinical role of preoperative fulcrum-bending and supine side-bending radiographs on the prediction of curve correction in adolescent idiopathic scoliosis.

PURPOSE: Preoperative curve assessment is important in adolescent idiopathic scoliosis (AIS). Our objective is to clarify the role of side-bending radiographs (SBR) and fulcrum-bending radiographs (FBR) in predicting postoperative Cobb angle in nonstructural and structural curves. METHODS: Twenty-five consecutive patients with AIS who underwent correction surgery were included. The Cobb angles of structural and nonstructural curves were determined. Cobb angles were measured based on pre- and postoperative standing anteroposterior radiographs of the whole spine. The Cobb angles of SBR and FBR were measured preoperatively. The difference between the Cobb angle at each bending and the preoperative Cobb angle was defined as the predicted correction angle, whereas the difference between the preoperative Cobb angle and postoperative Cobb angle was defined as the surgical correction angle. The correction index was calculated by dividing the surgical correction angle by the predicted correction angle. The difference between the predicted correction angle and surgical correction angle was defined as the prediction error. We compared SBR and FBR for both structural and nonstructural curves in these terms. RESULTS: For both curves, the predicted correction angle of FBR was significantly higher than that of SBR, and the correction index of FBR was significantly lower than that of SBR. Patients with a correction index close to 1 and small prediction error had undergone FBR in the structural curve and SBR in the nonstructural curve. CONCLUSION: FBR is predictive of postoperative correction angle of the structural curve, whereas SBR is predictive of postoperative correction angle of the nonstructural curve.

Development of a Retro-Odontoid pseudotumor in the absence of atlantoaxial instability or rheumatoid arthritis Post-Laminoplasty: case report.

A retro-odontoid pseudotumor (ROP) is commonly associated with atlantoaxial instability (AAI) or rheumatoid arthritis (RA). However, we describe a patient with ROP in the absence of AAI or RA. An 81-year-old man who did not have a history of trauma to the head and neck admitted with neck pain, right upper extremity numbness, lower limb weakness, and walking disturbance. He had a history of C2 dome and C3-7 laminoplasty 10 years ago. Magnetic resonance imaging revealed a retro-odontoid mass with cervical cord compression. Dynamic radiography did not show signs of AAI. He underwent C1 laminectomy without fixation for the ROP. We speculated that the load on C1 and C2 increased because of the progression of kyphosis from C2 to C7 with increases in range of motion, which in turn caused change in the biomechanics of the cervical spine, leading to recurrent partial tear and degradation of the transverse ligament that induced formation of the ROP. Spinal surgeons should keep this complication in mind and inform patients about this potential postoperative complication.

Utility of desflurane as an anesthetic in motor-evoked potentials in spine surgery and the facilitating effect in tetanic stimulation of bilateral median nerves.

Although desflurane is a safe and controllable inhalation anesthetic used in spinal surgery, to our knowledge, there have been no reports of successful motor-evoked potential (MEP) recordings under general anesthesia with desflurane alone. A high desflurane concentration may reduce the risk of intraoperative awareness but can also reduce the success of MEP recording. Therefore, we aimed to evaluate the reliability of MEP monitoring and investigate whether tetanic stimulation can augment MEP amplitude under general anesthesia with high-concentration desflurane during spinal surgery. We prospectively evaluated 46 patients who were scheduled to undergo lumbar surgery at a single center between 2018 and 2020. Anesthesia was maintained with an end-tidal concentration of 4% desflurane and remifentanil. Compound muscle action potentials were recorded bilaterally from the abductor pollicis brevis, abductor hallucis, tibialis anterior, gastrocnemius, and quadriceps. For post-tetanic MEPs (p-MEPs), tetanic stimulation was applied to the median nerves (p-MEPm) and tibial nerves (p-MEPt) separately before transcranial stimulation. The average success rates for conventional MEP (c-MEP), p-MEPm, and p-MEPt were 77.9%, 80%, and 79.3%, respectively. The p-MEPm amplitudes were significantly higher than the c-MEP amplitudes in all muscles (P < 0.05), whereas the p-MEPt amplitudes were not significantly different from the c-MEP amplitudes. The MEP recording success rates for the gastrocnemius and quadriceps were inadequate. However, bilateral median nerve tetanic stimulation can effectively augment MEPs safely under general anesthesia with high-concentration desflurane in patients who undergo spinal surgery.

New Spinal Shortening Technique for Tethered Cord Syndrome: A Technical Note.

Background and Objectives: To present a new spinal shortening technique for tethered cord syndrome. Tethered cord syndrome (TCS) is a debilitating condition leading to progressive neurological decline. Surgical detethering for TCS is the gold standard of treatment. However, symptomatic retethering of TCS has been reported in 5%-50% of patients after initial release. To solve this problem, posterior spinal shortening osteotomy has been reported. This technique has risks of massive blood loss and neurological deterioration. The authors hereby report a new safe spinal shortening technique for tethered cord syndrome. Materials and Methods: A 31-year-old man with gait disturbance was referred to our hospital. After the delivery of treatment, he underwent surgical untethering of the spinal cord in another hospital. He had hyperreflexia of the Achilles tendon reflex and bilateral muscle weakness of the legs (MMT 3-4). He also had urinary and bowel incontinence, and total sensory loss below L5. An anteroposterior lumbar radiogram indicated partial laminectomy of L3 and L4. Lumbar MRI showed retethering of spinal cord. Results: The patient underwent a new spinal shortening technique for tethered cord syndrome under the guidance of O-arm navigation. First, from the anterior approach, disectomy from T12 to L3 was performed. Second, from the posterior approach, Ponte osteotomy was performed from T12 to L3, shortening the spinal column by 15 mm. The patient was successfully treated surgically. Postoperative lumbar MRI showed that the tension of the spinal cord was released. Manual muscle testing results and the sensory function of the left leg had recovered almost fully upon final follow-up at one year. Conclusions: A retethered spinal cord after initial untethering is difficult to treat. This new spinal shortening technique can represent another good option to release the tension of the spinal cord.

Comparison of C-Arm-Free Oblique Lumbar Interbody Fusion L5-S1 (OLIF51) with Transforaminal Lumbar Interbody Fusion L5-S1 (TLIF51) for Adult Spinal Deformity.

Background and Objectives: Adult spinal deformity (ASD) surgery, L5-S1 lordosis is very important factor. The main objective of the research is to retrospectively compare symptomatic presentation and radiological presentation in the sequelae of oblique lumbar inter-body spinal fusion at L5-S1 (OLIF51) and transforaminal lumbar interbody fusion (TLIF) for ASD. Materials and Methods: We retrospectively evaluated 54 patients who underwent corrective spinal fusion for ASD between October 2019 and January 2021. Thirteen patients underwent OLIF51 (average 74.6 years old, group O) and 41 patients underwent TLIF51 (average 70.5 years old, group T). Mean follow-up period was 23.9 months for group O and 28.9 months for group T, ranging from 12 to 43 months. Clinical and radiographic outcomes are assessed using values including visual analogue scale (VAS) for back pain and Oswestry disability index (ODI). Radiographic evaluation was also collected preoperatively and at 6, 12, and 24 months postoperatively. Results: Surgical time in group O was less than that in group T (356 min vs. 492 min, p = 0.003). However, intraoperative blood loss of both groups were not significantly different (1016 mL vs. 1252 mL, p = 0.274). Changes in VAS and ODI were similar in both groups. L5-S1 angle gain and L5-S1 height gain in group O were significantly better than those of group T (9.4° vs. 1.6°, p = 0.0001, 4.2 mm vs. 0.8 mm, p = 0.0002). Conclusions: Clinical outcomes were not significantly different in both groups, but surgical time in OLIF51 was significantly less than that in TLIF51. The radiographic outcomes showed that OLIF51 created more L5-S1 lordosis and L5-S1 disc height compared with TLIF 51.

Fully Endoscopic Spine Separation Surgery in Metastatic Disease-Case Series, Technical Notes, and Preliminary Findings.

Objective: This report aims to describe the surgical methodology and potential effectiveness of endoscopic separation surgery (ESS) in patients with metastatic spine disease. This concept may reduce the invasiveness of the procedure, which can potentially speed up the wound healing process and, thus, the possibility of faster application of radiotherapy. Materials and Methods: In this study, separation surgery for preparing patients for stereotactic body radiotherapy (SBRT) was performed with fully endoscopic spine surgery (FESS) followed by percutaneous screw fixation (PSF). Results: Three patients with metastatic spine disease in the thoracic spine were treated with fully endoscopic spine separation surgery. The first case resulted in the progression of paresis symptoms that resulted in disqualification from further oncological treatment. The remaining two patients achieved satisfactory clinical and radiological effects and were referred for additional radiotherapy. Conclusions: With advancements in medical technology, such as endoscopic visualization, and new tools for coagulation, we can treat more and more spine diseases. Until now, spine metastasis was not an indication for the use of endoscopy. This method is very technically challenging and risky, especially at such an early stage of application, due to variations in the patient's condition, morphological diversity, and the nature of metastatic lesions in the spine. Further trials are needed to determine whether this new approach to treating patients with spine metastases is a promising breakthrough or a dead end.

A C-Arm-Free Minimally Invasive Technique for Spinal Surgery: Cervical and Thoracic Spine.

Background and Objectives: C-arm-free MIS techniques can offer significantly reduced rates of postoperative complications such as inadequate decompression, blood loss, and instrumentation misplacement. Another advantageous long-term aspect is the notably diminished exposure to radiation, which is known to cause malignant changes. This study emphasizes that, in some cases of spinal conditions that require a procedural intervention, C-arm-free MIS techniques hold stronger indications than open surgeries guided by image intensifiers. Materials and Methods: This study includes a retrospective analysis and review of various cervical and thoracic spinal procedures, performed in our hospital, applying C-arm-free techniques. The course of this study explains the basic steps of the procedures and demonstrates postoperative and intraoperative results. For anterior cervical surgery, we performed OPLL resection, while for posterior cervical surgery, we performed posterior fossa decompression for Chiari malformation, minimally invasive cervical pedicle screw fixation (MICEPS), and modified Goel technique with C1 lateral mass screw for atlantoaxial subluxation. Regarding the thoracic spine, we performed anterior correction for Lenke type 5 scoliosis and transdiscal screw fixation for diffuse idiopathic skeletal hyperostosis fractures. Results: C-arm-free techniques are safe procedures that provide precise and high-quality postoperative results by offering sufficient spine alignment and adequate decompression depending on the case. Navigation can offer significant assistance in the absence of normal anatomical landmarks, yet the surgeon should always appraise the quality of the information received from the software. Conclusions: Navigated C-arm-free techniques are safe and precise procedures implemented in the treatment of surgically demanding conditions. They can significantly increase accuracy while decreasing operative time. They represent the advancement in the field of spine surgery and are hailed as the future of the same.

Our C-Arm-Free Minimally Invasive Technique for Spinal Surgery: The Thoracolumbar and Lumbar Spine-Based on Our Experiences.

Background and Objectives: The implementation of intraoperative imaging in the procedures performed under the guidance of the same finds its history dating back to the early 1990s. This practice was abandoned due to many deficits and practicality. Later, fluoroscopy-dependent techniques were developed and have been used even in the present time, albeit with several disadvantages. With the recent advancement of several complex surgical techniques, which demand higher accuracy and are in conjunction with the existence of radiation exposure hazard, C-arm-free techniques were introduced. In this review study, we aim to demonstrate the various types of these techniques performed in our hospital. Materials and Methods: We have retrospectively analyzed and collected imaging data of C-arm-free, minimally invasive techniques performed in our hospital. The basic steps of the procedures are described, following with a discussion, along with the literature of findings, enlisting the merits and demerits. Results: MIS techniques of the thoracolumbar and lumbar spine that do not require the use of the C-arm can offer excellent results with high precision. However, several disadvantages may prevail in certain circumstances such as the navigation accuracy problem where in the possibility of perioperative complications comes a high morbidity rate. Conclusions: The accustomedness of performing these techniques requires a steep learning curve. The increase in accuracy and the decrease in radiation exposure in complex spinal surgery can overcome the burden hazards and can prove to be cost-effective.

Antibody Screening System Using a Herpes Simplex Virus (HSV)-Based Probe To Identify a Novel Target for Receptor-Retargeted Oncolytic HSVs.

Herpes simplex virus (HSV) is a promising tool for developing oncolytic virotherapy. We recently reported a platform for receptor-retargeted oncolytic HSVs that incorporates single-chain antibodies (scFvs) into envelope glycoprotein D (gD) to mediate virus entry via tumor-associated antigens. Therefore, it would be useful to develop an efficient system that can screen antibodies that might mediate HSV entry when they are incorporated as scFvs into gD. We created an HSV-based screening probe by the genetic fusion of a gD mutant with ablated binding capability to the authentic HSV entry receptors and the antibody-binding C domain of streptococcal protein G. This engineered virus failed to enter cells through authentic receptors. In contrast, when this virus was conjugated with an antibody specific to an antigen on the cell membrane, it specifically entered cells expressing the cognate antigen. This virus was used as a probe to identify antibodies that mediate virus entry via recognition of certain molecules on the cell membrane other than authentic receptors. Using this method, we identified an antibody specific to epiregulin (EREG), which has been investigated mainly as a secreted growth factor and not necessarily for its precursor that is expressed in a transmembrane form. We constructed an scFv from the anti-EREG antibody for insertion into the retargeted HSV platform and found that the recombinant virus entered cells specifically through EREG expressed by the cells. This novel antibody-screening system may contribute to the discovery of unique and unexpected molecules that might be used for the entry of receptor-retargeted oncolytic HSVs.IMPORTANCE The tropism of the cellular entry of HSV is dependent on the binding of the envelope gD to one of its authentic receptors. This can be fully retargeted to other receptors by inserting scFvs into gD with appropriate modifications. In theory, upon binding to the engineered gD, receptors other than authentic receptors should induce a conformational change in the gD, which activates downstream mechanisms required for viral entry. However, prerequisite factors for receptors to be used as targets of a retargeted virus remain poorly understood, and it is difficult to predict which molecules might be suitable for our retargeted HSV construct. Our HSV-based probe will allow unbiased screening of antibody-antigen pairs that mediate virus entry and might be a useful tool to identify suitable pairs for our construct and to enhance our understanding of virus-cell interactions during infection by HSV and possibly other viruses.