Bifunctional DEGS2 has higher hydroxylase activity toward substrates with very-long-chain fatty acids in the production of phytosphingosine ceramides.

Phytosphingosine (PHS) is a sphingolipid component present mainly in epithelial tissues, including the epidermis and those lining the digestive tract. DEGS2 is a bifunctional enzyme that produces ceramides (CERs) containing PHS (PHS-CERs) via hydroxylation and sphingosine-CERs via desaturation, using dihydrosphingosine-CERs as substrates. Until now, the role of DEGS2 in permeability barrier functioning, its contribution to PHS-CER production, and the mechanism that differentiates between these two activities have been unknown. Here, we analyzed the barrier functioning of the epidermis, esophagus, and anterior stomach of Degs2 KO mice and found that there were no differences between Degs2 KO and WT mice, indicating normal permeability barriers in the KO mice. In the epidermis, esophagus, and anterior stomach of Degs2 KO mice, PHS-CER levels were greatly reduced relative to WT mice, but PHS-CERs were still present. We obtained similar results for DEGS2 KO human keratinocytes. These results indicate that although DEGS2 plays a major role in PHS-CER production, another synthesis pathway exists as well. Next, we examined the fatty acid (FA) composition of PHS-CERs in various mouse tissues and found that PHS-CER species containing very-long-chain FAs (≥C21) were more abundant than those containing long-chain FAs (C11-C20). A cell-based assay system revealed that the desaturase and hydroxylase activities of DEGS2 toward substrates with different FA chain lengths differed and that its hydroxylase activity was higher toward substrates containing very-long-chain FAs. Collectively, our findings contribute to the elucidation of the molecular mechanism of PHS-CER production.

Usefulness of the Three-step Simple Binostril Approach in Endoscopic Endonasal Transsphenoidal Surgery.

We describe a three-step, simple binostril approach to endoscopic endonasal transsphenoidal surgery in cases of sellar/parasellar lesions. In the first step, the mucosa of the lower third of the ethmoid bulla on the outside was coagulated with monopolar microdissection needle and opened to create space on the outside of the middle turbinate. The middle turbinate was moved outward using this space, and the natural ostium of the sphenoid sinus could be confirmed easily. In the second step, a less than 10 mm incision was made from the right natural ostium of the sphenoid sinus to the right nasal septal mucosa. The anterior wall of the sphenoid sinus was removed to free the sphenoid sinus. In the third step, the instrument was inserted through the left nostril using a hole connected to the natural ostium of the sphenoid sinus to reach the sellar floor via both nostrils. It took longer for the trainee than for the instructor to reach the sellar floor in the first four cases. However, there was no significant difference in the approach time after the fifth case. Approach-related postoperative complications were observed in 52 cases of sellar/parasellar lesions performed. This approach was considered to provide sufficient space and was simple and less burdensome to the patient.

Usefulness and problems of Y-Stent and T-Stent assisted coiling for unruptured cerebral aneurysms.

INTRODUCTION: We are going to discuss about usefulness and problems of Y-stent and T-stent assisted coiling for unruptured cerebral aneurysms. METHODS: A retrospective review was performed to identify patients who were treated using Y-stent or T-stent assisted coiling (Y-SAC, T-SAC) for 25 unruptured cerebral aneurysms from April 2017 to September 2021. Fifteen cases were treated using Y-SAC, 10 were done using T-SAC. Only a case was treated with Low-profile Visualized Intraluminal Support (LVIS; MicroVention TRUMO, Aliso Viejo, California, USA) and Neuroform ATLAS (Striker, Kalamazoo, Michigan, USA), Others were done with two Neuroform ATLAS stents. RESULTS: Y-SAC and T-SAC were succeeded in all cases. In two cases that were treated using Y-SAC, ischemic complications were observed. A patient received additional embolization because subarachnoid hemorrhage (SAH) was appeared after discharge. On follow-up imaging, complete occlusion (CO) was confirmed in all cases. CONCLUSION: The position of deployment of stents was the most important issue. In particular, the second stent should be deployed as to contact the first stent, as possible. The case that the position of the second stent was shifted, and neck was not covered was observed. In the cases that are treated by using T-SAC, microcatheter must be navigated to distal position as possible. In that point, Y-SAC is more applicable. The familiarization of Y-SAC or T-SAC will expand the indication of endovascular treatment for unruptured cerebral aneurysms.

Successful use of an LVIS device to treat unruptured distal aneurysm of the superior cerebellar artery at a vascular bifurcation.

Background: Aneurysms of the distal superior cerebellar artery (SCA) account for only a small proportion of all cerebral aneurysms. Reports of the use of flow diverters (FDs) started to appear in 2013. We obtained good results from placement of a low-profile visualized intraluminal support device (LVIS) to treat unruptured distal aneurysm of the SCA at a vascular bifurcation. Case Description: A 65-year-old man presented at our hospital with sudden peripheral facial nerve palsy and suspected subarachnoid hemorrhage. Investigational cerebral angiography revealed an aneurysm at the bifurcation of the caudal and rostral trunks of the SCA. An LVIS was placed with the aim of obtaining flow diversion, and cerebral angiography 6 months after this procedure showed disappearance of aneurysm with preservation of the distal SCA. Conclusion: Twelve cases of the use of FDs to treat aneurysms of the SCA have been reported previously. However, none of those reports described FD use to treat an aneurysm at a vascular bifurcation, as in the present case. Our results suggested that LVIS placement with the aim of obtaining flow diversion may be useful for the treatment of aneurysms at such sites.

Usefulness of endoscope-assisted surgery under exoscopic view in skull base surgery: A technical note.

BACKGROUND: The use of the exoscope has been increasing in the field of neurosurgery, as it can set the visual axis freely, enabling the surgeon to operate in a comfortable posture. Although endoscope-assisted surgery for compensation of insufficient surgical field is useful under the microscope, we report that using an endoscope in exoscopic surgery is safer and more useful. METHODS: The exoscope used was ORBEYE. All surgical procedures were performed exoscopically from the beginning of the surgery. When endoscopic observation was required during the operation, the endoscope was inserted under observation by an exoscope. The exoscopic screen was 4K-3D and endoscopic screen was 4K-2D, the operation was performed while observing both screens at the same time. The endoscope was held manually or by a mechanical holder. RESULTS: Twenty-two cases, including 14 requiring microvascular decompression (MVD) and eight requiring tumor removal, were performed by endoscopic-assisted exoscopic surgery. The endoscope could be inserted safely because its relationship with the surrounding structure could be observed under the exoscope, and the operator could observe both screens without moving the head. Fourteen of 22 patients required additional endoscopic treatment. Satisfactory two-handed operation was performed in 13 cases. Symptomatology disappeared in all cases of MVD, and sufficient tumor resection was achieved. CONCLUSION: Exoscopic surgery provides excellent surgical view that is not inferior to conventional microsurgery. As a large space can be secured between the scope and the surgical field, it is safer and easier to manipulate the endoscope under the exoscope.

Synthesis, Crystal Structure, and Photoluminescent Properties of 3,3',4,4'-Tetraethyl-5,5'-divinyl-2,2'-bipyrrole Derivatives.

Photoluminescent divinylbipyrroles were synthesized from 3,3',4,4'-tetraetyl-2,2'-bipyrrole-5,5'-dicarboxaldehyde and activated methylene compounds via aldol condensation. For mechanistic clarity, molecular structures of Meldrum's acid- and 1,3-dimethylbarbituric acid-derived divinylbipyrroles were determined by single-crystal X-ray diffraction. Photoluminescent properties of the synthesized divinylbipyrroles in dichloromethane were found to be dependent on the presence of electron withdrawing groups at the vinylic terminal. The divinylbipyrroles derived from malononitrile, Meldrum's acid, and 1,3-dimethylbarbituric acid showed fluorescent peaks at 553, 576, and 602 nm respectively. Computational studies indicated that the alkyl substituents on the bipyrrole 3 and 3' positions increased energy level of the highest occupied molecular orbital (HOMO) compared to the unsubstituted derivatives and provided rationale for the bathochromic shift of the ultraviolet-visible (UV-Vis) spectra compared to the previously reported analogs.