A novel omnidirectional tin-alloyed ring retractor for craniotomy in neurosurgery: technical note.

In neurosurgical operations, proper craniotomy using retractors is necessary. Various surgical instruments are used for this purpose, including standard retractors and multipurpose head frame retractor systems. However, the conventional multipurpose head frame system is often not optimal for use in some craniotomies and postures because of its size and complexity of setting. We have invented a new omnidirectional tin-alloyed (ODT) ring retractor for craniotomy with malleability and shape memory characteristics to resolve these issues. It is principally elliptical in shape, approximately 30 × 20 cm in diameter, and sufficiently firm. Accordingly, this ODT ring can retract the surgical field in all directions. Here, we report our experiences of 281 neurosurgical craniotomies using this ODT ring retractor system in various craniotomy sites and postures. Our novel ODT ring retractor is useful because of its low profile, multidirectional retractability, and less obstructiveness with its malleability. It could be used with pediatric patients where strong traction is not desirable.

Molecular Characteristics of DNA-Alkylating PI Polyamides Targeting RUNX Transcription Factors.

The runt-related transcription factor (RUNX) family has been associated with cancer development. The binding of RUNX family members to specific DNA sequences is hypothesized to promote the expression of downstream genes and cause cancer proliferation. On the basis of this proposed mechanism of cancer growth, we developed conjugate 1, which inhibits the binding of RUNX to its target DNA. Conjugate 1 is a DNA-alkylating pyrrole-imidazole (PI) polyamide conjugate containing chlorambucil as an anticancer agent. Conjugate 1 was reported to have a marked anticancer effect in mouse models of acute myeloid leukemia. Although the effectiveness of 1 has been demonstrated in vivo, the detailed mechanism by which it alkylates DNA is unknown. Here, we chemically elucidated the molecular characteristics of conjugate 1 to confirm its potential as a RUNX-inhibiting drug. We also generated an alternative conjugate 2, which targets the same DNA sequence, by replacing one pyrrole with ß-alanine. Comparison of the characteristics of conjugates 1 and 2 suggested that reaction selectivity and binding affinity to the RUNX-binding sequence were improved by the introduction of ß-alanine. These findings indicate the possibility of DNA-alkylating PI polyamides as candidates for cancer chemotherapeutics.

Orientation preferences of hairpin pyrrole-imidazole polyamides toward mCGG site.

Hairpin pyrrole-imidazole (Py-Im) polyamides are promising medium-sized molecules that bind sequence-specifically to the minor groove of B-form DNA. Here, we synthesized a series of hairpin Py-Im polyamides and explored their binding affinities and orientation preferences to methylated DNA with the mCGG target sequence. Thermal denaturation assays revealed that the five hairpin Py-Im polyamides, which were anticipated to recognize mCGG in a forward orientation, bind to nontarget DNA, GGmC, in a reverse orientation. Therefore, we designed five Py-Im polyamides that could recognize mCGG in a reverse orientation. We found that the two Py-Im polyamides containing Im/ß pairs preferentially bound to mCGG in a reverse orientation. The reverse binding Py-Im polyamide successfully inhibited TET1 binding on the methylated DNA. Taken together, this study illustrated the importance of designing reverse binding Py-Im polyamides for the target sequence, mCGG, which paved the way for Py-Im polyamides that can be used with otherwise difficult to access DNA with CG sequences.

Deciphering the genomic targets of alkylating polyamide conjugates using high-throughput sequencing.

Chemically engineered small molecules targeting specific genomic sequences play an important role in drug development research. Pyrrole-imidazole polyamides (PIPs) are a group of molecules that can bind to the DNA minor-groove and can be engineered to target specific sequences. Their biological effects rely primarily on their selective DNA binding. However, the binding mechanism of PIPs at the chromatinized genome level is poorly understood. Herein, we report a method using high-throughput sequencing to identify the DNA-alkylating sites of PIP-indole-seco-CBI conjugates. High-throughput sequencing analysis of conjugate 2: showed highly similar DNA-alkylating sites on synthetic oligos (histone-free DNA) and on human genomes (chromatinized DNA context). To our knowledge, this is the first report identifying alkylation sites across genomic DNA by alkylating PIP conjugates using high-throughput sequencing.

Genome-Wide Assessment of the Binding Effects of Artificial Transcriptional Activators by High-Throughput Sequencing.

One of the major goals in DNA-based personalized medicine is the development of sequence-specific small molecules to target the genome. SAHA-PIPs belong to such class of small molecule. In the context of the complex eukaryotic genome, the differential biological effects of SAHA-PIPs are unclear. This question can be addressed by identifying the binding regions across the genome; however, it is a challenge to enrich small-molecule-bound DNA without chemical crosslinking. Here, we developed a method that employs high-throughput sequencing to map the binding area of small molecules throughout the chromatinized human genome. Analysis of the sequenced data confirmed the presence of specific binding sites for SAHA-PIPs from the enriched sequence reads. Mapping the binding sites and enriched regions on the human genome clarifies the reason for the distinct biological effects of SAHA-PIP. This approach will be useful for identifying the function of other small molecules on a large scale.

Sequence-specific DNA binding by long hairpin pyrrole-imidazole polyamides containing an 8-amino-3,6-dioxaoctanoic acid unit.

With the aim of improving aqueous solubility, we designed and synthesized five N-methylpyrrole (Py)-N-methylimidazole (Im) polyamides capable of recognizing 9-bp sequences. Their DNA-binding affinities and sequence specificities were evaluated by SPR and Bind-n-Seq analyses. The design of polyamide 1 was based on a conventional model, with three consecutive Py or Im rings separated by a ß-alanine to match the curvature and twist of long DNA helices. Polyamides 2 and 3 contained an 8-amino-3,6-dioxaoctanoic acid (AO) unit, which has previously only been used as a linker within linear Py-Im polyamides or between Py-Im hairpin motifs for tandem hairpin. It is demonstrated herein that AO also functions as a linker element that can extend to 2-bp in hairpin motifs. Notably, although the AO-containing unit can fail to bind the expected sequence, polyamide 4, which has two AO units facing each other in a hairpin form, successfully showed the expected motif and a KD value of 16nM was recorded. Polyamide 5, containing a ß-alanine-ß-alanine unit instead of the AO of polyamide 2, was synthesized for comparison. The aqueous solubilities and nuclear localization of three of the polyamides were also examined. The results suggest the possibility of applying the AO unit in the core of Py-Im polyamide compounds.

Synthesis and biological evaluation of a targeted DNA-binding transcriptional activator with HDAC8 inhibitory activity.

Development of multifunctional transcriptional activators is of increasing importance as they could trigger complicated gene networks. Recently, we developed a differential gene activating multifunctional small molecule SAHA-PIP (Sδ) by conjugating a histone deacetylase (HDAC) inhibitor, SAHA, to a selective DNA-binding pyrrole-imidazole polyamide (PIP). Epigenetic activity of Sδ was attributed to the active metal-binding (-NHOH) domain of SAHA. We synthesized a derivative of Sδ, called Jδ to evaluate the role of surface recognition domain (-phenyl) of SAHA in Sδ-mediated transcriptional activation. In vitro studies revealed that Jδ displayed potent inhibitory activity against HDAC8. Jδ retained the pluripotency gene-inducing ability of Sδ when used alone and in combination with Sδ; a notable increase in the pluripotency gene expression was observed. Interestingly, Jδ significantly induced the expression of HDAC8-controlled Otx2 and Lhx1. Our results suggest that the epigenetic activity of our multifunctional molecule could be altered to improve its efficiency as a transcriptional activator for intricate gene network(s).

Anticancer Activities of DNA-Alkylating Pyrrole-Imidazole Polyamide Analogs Targeting RUNX Transcription Factors against p53-Mutated Pancreatic Cancer PANC-1 Cells.

The runt-related transcription factor (RUNX) family is known to play important roles in the progression of cancer. Conjugate 1, which covalently binds to the RUNX-binding sequences, was reported to inhibit the binding of RUNX proteins to their target sites and suppress cancer growth. Here, we evaluated the anticancer effects of 1 and its analogs 2-4 against p53-mutated PANC-1 pancreatic cancer cells. We found that they possessed different DNA-alkylating properties in vitro. And conjugates 1-3 were shown to have anticancer effects by inducing apoptosis in PANC-1 cells. Furthermore, conjugates 2 and 3 suppressed cancer growth in PANC-1 xenograft mice, with activity equivalent to a 50-fold dose of gemcitabine. Especially, 3 showed the highest alkylation efficiency, specificity, and better anticancer effects against pancreatic cancer than 1 in vivo without significant body weight loss. Our results revealed the potential of our compounds as new candidates for cancer therapy.

Development of programmable small DNA-binding molecules with epigenetic activity for induction of core pluripotency genes.

Epigenetic modifications that govern the gene expression are often overlooked with the design of artificial genetic switches. N-Methylpyrrole-N-methylimidazole (PI) hairpin polyamides are programmable small DNA binding molecules that have been studied in the context of gene regulation. Recently, we synthesized a library of compounds by conjugating PI polyamides with SAHA, a chromatin-modifier. Among these novel compounds, PI polyamide-SAHA conjugate 1 was shown to epigenetically activate pluripotency genes in mouse embryonic fibroblasts. Here, we report the synthesis of the derivatives of conjugate 1 and demonstrate that these epigenetically active molecules could be developed to improve the induction of pluripotency factors.

A case of pediatric paraspinal arteriovenous fistula with multiple fistulas.

Paraspinal arteriovenous fistula (AVF) is a rare vascular malformation. This is the first described case of a pediatric paraspinal AVF along nonvertebral segmental nerve with multiple fistulas. An 8 months-old girl was found to have a continuous murmur on the back on chest auscultation. Enhanced computed tomography revealed a segmental nerve AVF of the right thoracic spine. Selective angiography of the right T8 and T9 intercostal arteries demonstrated a high flow fistula at the level of the neural foramen, with drainage to the epidural and azygos veins. The fistulas point was visualized using Volume rendering(VR) and Minimum Intensity Projection(MIP) images. Endovascular treatment from the right T8 and T9 feeding arteries was provided using coils and n-butyl-2-cyanoacrylate(NBCA). Postembolization angiography demonstrated complete occlusion of the fistulas. The postoperative course was uneventful. We discuss the first case of a pediatric paraspinal AVF along nonvertebral segmental nerve with double holes of fistulas with literature review.

Video-assisted esophagectomy using a port-free organ retractor for the prevention of laryngeal nerve paralysis.

INTRODUCTION: Recurrent laryngeal nerve (RLN) paralysis is a major complication of esophageal cancer surgery. The free jaw clip (FJ clip) was developed as an organ-retracting device, and it can also reduce the number of ports required during surgery. Here, we describe a new technique for lymphadenectomy along the left RLN using the FJ clip. MATERIALS AND SURGICAL TECHNIQUE: After the middle and lower mediastinal lymph nodes were dissected, the upper esophagus and other tissues, including the lymph nodes and left RLN, were retracted by cutting the tracheal arteries between the esophagus and trachea and then pulling the upper esophagus to the dorsal side with the FJ clip. The esophagus was transected at the upper mediastinum, and the proximal esophagus was drawn by the FJ clip. This technique helped provide a good field of view during lymphadenectomy along the left RLN. The data of nine consecutive patients who underwent video-assisted esophagectomy in the left lateral decubitus position by the same surgeon were reviewed. Postoperative left RLN paralysis occurred in only one patient in whom the RLN could not be preserved. DISCUSSION: Given the excellent short-term outcomes with respect to left RLN paralysis, lymphadenectomy along the left RLN using the FJ clip was safe and feasible.

Transvenous embolization for craniocervical junction epidural arteriovenous fistula with a pial feeder aneurysm.

Arteriovenous fistulas at the craniocervical junction are rare vascular malformations with frequent hemorrhagic presentations, which may have a concurrent pial feeder aneurysm. A 65-year-old man presented with subarachnoid hemorrhage and angiography showed an epidural arteriovenous fistula at the C-2 level with an anterior spinal feeder aneurysm without perimedullary venous drainage. Transarterial coil embolization of the ruptured aneurysm and partial Onyx embolization of the shunt led to thrombosis of the aneurysm. However, three years later angiography showed an increased shunt flow and recurrence of the aneurysm. Transvenous embolization of the shunt using coils and Onyx yielded complete obliteration of the shunt, thus leading to occlusion of the aneurysm. This case demonstrates that partial transarterial embolization of arteriovenous fistula leaves a risk of rebleeding, whereas complete obliteration of the shunt with a transvenous approach can lead to disappearance of the flow-related aneurysm without embolization of the aneurysm itself.

Omnidirectional Malleable Ring Retractor: New Approach to Retraction During Carotid Endarterectomy.

OBJECTIVE: To resolve problems with retraction instruments in order to obtain shallow and flat operative field in procedures such as carotid endarterectomy, we developed a new malleable tin alloy omnidirectional retraction supporting (ORS) ring. METHODS: The new ORS ring has an ellipse-shaped (major axis: 275 mm; minor axis: 192 mm) bar frame (4 mm × 6 mm). The bar has 22 equidistant outward protrusions (length, 12 mm; diameter, 2.5 mm). The frame is made of tin alloy with approximately 1% silver, which provides sufficient malleability to fit different cervical surgical approaches. Rubber bands ending with hooks are attached around the protrusions. The new ORS ring can be placed closer to the skin surface, and skin incision edges are horizontally retracted by the hooks attached in the desired direction. The hooks are repositioned in a stepwise fashion at deeper layers of the surgical wound following dissection for carotid artery exposure. RESULTS: The tin alloy ORS ring was used in 30 carotid endarterectomies. As this ring could be closely positioned in all cases, the real depth of the operative fields (with all instruments in place) was reduced by the omnidirectional horizontal retraction without interference with surgical manipulations. Working on the distal internal carotid artery, such as putting a tacking suture in place and arteriotomy closure, could be easily performed. CONCLUSIONS: The newly developed malleable tin alloy ORS ring can be a valuable instrument for the easy performance of surgery for cervical carotid lesions. Considering its advantages, it is better than conventional retractors and existing stainless steel ORS rings.

Novel Malleable Continuous Suction Tube Made of Ultrathin Stainless-Steel Foil Enclosed Between 2 Ultrafine Mesh Layers: Technical Note.

BACKGROUND: Bloodless dry fields are indispensable for successful and safe neurosurgical operations using microscopes. Appropriate irrigation and suction systems are needed to obtain clear surgical fields. We invented a novel malleable continuous suction tube to address this need. METHODS: We developed a malleable tube (MT) made of ultrathin stainless-steel foil (≈5 µm in thickness, 3.0 mm in diameter, 15 cm in length) contained between ultrafine stainless-steel wire mesh (50 µm in diameter) woven tubes. The MT was applied in an intraoperative continuous fluid suction system, connecting it to a conventional vacuum system through a device. RESULTS: The MT can be placed at any part of the operative field, preferably close to its edges, without disturbing surgeon manipulation. This continuous suction system has been tested in neurosurgical operations and has shown excellent potential for maintaining the operative field clear and dry without any side effect or trauma on adjacent tissues. CONCLUSIONS: The newly developed malleable suction tube is effective for microsurgery.

The Availability of a Tin-Alloyed Omnidirectional Retractor-Supporting Ring for Ventriculoperitoneal Shunt Laparotomy.

OBJECTIVE: We report the availability of a newly developed, malleable, tin-alloyed omnidirectional retractor-supporting (OD) ring for steady and safe ventriculoperitoneal (VP) shunt laparotomy. METHODS: The OD ring is principally circular in shape, 15 cm in diameter, and is sufficiently malleable to be fitted to the abdominal wall. There are 22 outward protrusions 12 mm in length that are welded to the outside of the ring at regular intervals. The OD ring with twisted rubber bands attached around the protrusions is placed on the abdominal wall surrounding the skin incision. Then the edge is omnidirectionally retracted with blunt minihooks attached to the rubber bands. In our hospital from January 2016 to February 2017, 15 consecutive patients underwent a VP shunt procedure using the OD ring. RESULTS: In a VP shunt procedure, our malleable, tin-alloyed OD ring could be smoothly placed on various types of abdominal walls. Moreover, our OD ring system provided a wider and shallower operative field allowing omnidirectional retraction during small laparotomy. Additionally, the OD ring system did not interfere with our surgical manipulations. CONCLUSIONS: Our newly developed retraction system with a malleable, tin-alloyed OD ring and minihooks may allow safe and steady small laparotomy for VP shunt.

Identification of a small molecule that turns ON the pluripotency gene circuitry in human fibroblasts.

A nontransgenic approach to reprogram mouse somatic cells into induced pluripotent stem cells using only small molecules got achieved to propose a potential clinical-friendly cellular reprogramming strategy. Consequently, the screening and identification of small molecules capable of inducing pluripotency genes in human cells are increasingly a focus of research. Because cellular reprogramming is multifactorial in nature, there is a need for versatile small molecules capable of modulating the complicated gene networks associated with pluripotency. We have developed a targeting small molecule called SAHA-PIP comprising the histone deacetylase inhibitor SAHA and the sequence-specific DNA binding pyrrole-imidazole polyamides for modulating distinct gene networks. Here, we report the identification of a SAHA-PIP termed Ì that could trigger genome-wide epigenetic reprogramming and turn ON the typically conserved core pluripotency gene network. Through independent lines of evidence, we report for the first time a synthetic small molecule inducer that target and activate the OCT-3/4 regulated pluripotency genes in human dermal fibroblasts.

Targeted suppression of EVI1 oncogene expression by sequence-specific pyrrole-imidazole polyamide.

Human ectopic viral integration site 1 (EVI1) is an oncogenic transcription factor known to play a critical role in many aggressive forms of cancer. Its selective modulation is thought to alter the cancer-specific gene regulatory networks. Pyrrole-imidazole polyamides (PIPs) are a class of small DNA binders that can be designed to target any destined DNA sequence. Herein, we report a sequence-specific pyrrole-imidazole polyamide, PIP1, which can target specific base pairs of the REL/ELK1 binding site in the EVI1 minimal promoter. The designed PIP1 significantly inhibited EVI1 in MDA-MB-231 cells. Whole-transcriptome analysis confirmed that PIP1 affected a fraction of EVI1-mediated gene regulation. In vitro assays suggested that this polyamide can also effectively inhibit breast cancer cell migration. Taken together, these results suggest that EVI1-targeted PIP1 is an effective transcriptional regulator in cancer cells.

Distinct DNA-based epigenetic switches trigger transcriptional activation of silent genes in human dermal fibroblasts.

The influential role of the epigenome in orchestrating genome-wide transcriptional activation instigates the demand for the artificial genetic switches with distinct DNA sequence recognition. Recently, we developed a novel class of epigenetically active small molecules called SAHA-PIPs by conjugating selective DNA binding pyrrole-imidazole polyamides (PIPs) with the histone deacetylase inhibitor SAHA. Screening studies revealed that certain SAHA-PIPs trigger targeted transcriptional activation of pluripotency and germ cell genes in mouse and human fibroblasts, respectively. Through microarray studies and functional analysis, here we demonstrate for the first time the remarkable ability of thirty-two different SAHA-PIPs to trigger the transcriptional activation of exclusive clusters of genes and noncoding RNAs. QRT-PCR validated the microarray data, and some SAHA-PIPs activated therapeutically significant genes like KSR2. Based on the aforementioned results, we propose the potential use of SAHA-PIPs as reagents capable of targeted transcriptional activation.

Therapeutic effects of gelatin-resorcin-formal glue in the treatment of postoperative fistula following a low anterior resection: report of a case.

Postoperative fistulas are among the most difficult and distressing of surgical problems. We describe a case of a discharging fistula that developed after low anterior resection and was successfully treated with a new biologic adhesive agent, gelatin-resorcin-formal glue. To our knowledge, this is the first reported case of a postoperative fistula after colorectal surgery successfully treated with gelatin-resorcin-formal glue. In conclusion, gelatin-resorcin-formal glue is useful for uncontrollable postoperative fistula.