Seiji Komatsu

The Neutral Self-Assembling Peptide Hydrogel SPG-178 as a Topical Hemostatic Agent

Conventional self-assembling peptide hydrogels are effective as topical hemostatic agents. However, there is a possibility to harm living tissues due to their low pH. The aim of the present study was to demonstrate the efficacy of SPG-178, a neutral self-assembling peptide hydrogel, as a topical hemostatic agent. First, we measured the bleeding duration of incisions made on rat livers after application of SPG-178 (1.0% w/v), SPG-178 (1.5% w/v), RADA16 (1.0% w/v), and saline (n = 12/group). Second, we observed the bleeding surfaces by transmission electron microscopy immediately after hemostasis. Third, we measured the elastic and viscous responses (G′ and G″, respectively) of the hydrogels using a rheometer. Our results showed that bleeding duration was significantly shorter in the SPG-178 group than in the RADA16 group and that there were no significant differences in transmission electron microscopy findings between the groups. The greater the G′ value of a hydrogel, the shorter was the bleeding duration. We concluded that SPG-178 is more effective and has several advantages: it is non-biological, transparent, nonadherent, and neutral and can be sterilized by autoclaving.

Modification of Fe–Ni Invar alloys by high-energy ion beams

Abstract Measurements of temperature dependence of AC-susceptibility were made in Fe–30.2at.%Ni Invar alloy before and after 100 MeV Xe ion irradiation up to the dose of 10 14 ions/cm 2 . Measurements were performed at various angles θ between the direction of the ion beam and the external AC-magnetic field. It was found that in partially irradiated area, locally ferromagnetic parts exist at temperatures above the Curie temperature of the body where high-energy ions did not penetrate. The easy axis of the locally ferromagnetic parts was determined to be parallel to the beam direction. Those locally ferromagnetic parts can be considered to be in thin needle-like shape. This type of modification has a possibility of applications for perpendicular high-density memory and giant magneto-resistance materials.

Evaluation of the Microvascular Research Center Training Program for Assessing Microsurgical Skills in Trainee Surgeons

Background We established the Microvascular Research Center Training Program (MRCP) to help trainee surgeons acquire and develop microsurgical skills. Medical students were recruited to undergo the MRCP to assess the effectiveness of the MRCP for trainee surgeons. Methods Twenty-two medical students with no prior microsurgical experience, who completed the course from 2005 to 2012, were included. The MRCP comprises 5 stages of training, each with specific passing requirements. Stages 1 and 2 involve anastomosing silicone tubes and blood vessels of chicken carcasses, respectively, within 20 minutes. Stage 3 involves anastomosing the femoral artery and vein of live rats with a 1-day patency rate of >80%. Stage 4 requires replantation of free superficial inferior epigastric artery flaps in rats with a 7-day success rate of >80%. Stage 5 involves successful completion of one case of rat replantation/transplantation. We calculated the passing rate for each stage and recorded the number of anastomoses required to pass stages 3 and 4. Results The passing rates were 100% (22/22) for stages 1 and 2, 86.4% (19/22) for stage 3, 59.1% (13/22) for stage 4, and 55.0% (11/20) for stage 5. The number of anastomoses performed was 17.2±12.2 in stage 3 and 11.3±8.1 in stage 4. Conclusions Majority of the medical students who undertook the MRCP acquired basic microsurgical skills. Thus, we conclude that the MRCP is an effective microsurgery training program for trainee surgeons.

Vascularized peripheral nerve grafting promotes myelination of regrowing optic nerve.

We investigated whether the use of vascularized peripheral nerve grafts on the optic nerve stump enhances axonal regeneration of retinal ganglion cells compared with isolated nonvascularized grafts. The rat median nerve was microsurgically sutured with its supplying artery and vein to the optic nerve stump. The number of retinal ganglion cells with regenerating axons was evaluated by retrograde labeling into the grafted peripheral nerve, and the myelination of the regenerating axon fibers was examined by electron microscopy. The number of retinal ganglion cells with regenerating axons was significantly higher in the vascularized graft than in the nonvascularized graft. The ratio of myelinated axon fibers was also increased in vascularized grafts. Thus, grafting with their supplying arteries and veins to an injured nerve stump represents a promising strategy to accelerate axonal regeneration from neurons of the central nervous system.

Pedicled buccal fat pad for the augmentation of facial depression deformity: A case report

Rationale: Tissue augmentation of facial depression deformities can be achieved by volume replacement with autologous fat injection, dermal filler injection, etc. Here, we report a case of tissue augmentation of a facial depression deformity using a pedicled buccal fat pad (BFP). Patient concerns: A 64-year-old woman was referred with a chief complaint of facial depression deformity. Diagnoses: Her molars had been removed at another hospital 12 years prior to this referral, and the patient suffered from a left cheek depression deformity as a sequela of a postextraction infection. Interventions: An incision was made in the left gingivobuccal sulcus under local anesthesia, and BFP was carefully excised from its normal location. The subcutaneous scar tissue was dissected, and a pocket was created via the same mucosal incision. BFP was then pushed into the pocket. Outcomes: The depression deformity immediately disappeared postoperatively. The transplanted BFP remained unabsorbed and soft 43 months postoperatively. The patient did not have any complications. Lessons: This novel procedure has 2 advantages. First, the pedicled BFP is a vascularized tissue and is not absorbed postoperatively; control of contour is easy, and only 1 treatment session is required. Complications associated with fat necrosis can be avoided. Second, only a single intraoral incision is required; the risk of donor-site morbidity is very low, and scar formation does not occur on exposed skin. Third, this procedure can be performed without special instruments and equipment. The main disadvantages are limited rotation arc and volume of pedicled BFP. Despite its limited application, this procedure is simple and useful, with low invasiveness.

S-shaped Wound Closure Technique for Dumbbell-shaped Keloids

Summary: Dog-ear collection, Z-plasty, and W-plasty are often performed for excision of dumbbell-shaped keloids; however, these procedures require additional incisions or excision of normal skin. Thus, an S-shaped wound closure technique was performed. The keloid lesions were extralesionally excised above the deep fascia, and the wound edges were shifted in opposite directions along the major axis to form an S-shape. The incision was closed by applying deep fascial sutures, subcutaneous sutures, and superficial sutures. Postoperative external beam radiation therapy was started within 6 hours after surgery at a dose of 20 Gy applied in 4 fractions. All wounds were covered with silicone-gel sheeting and fixed with tape after suture removal. No intralesional corticosteroid injection or oral tranilast was administered. Corticosteroid tape was applied in cases with suspected postoperative recurrence. Scoring was performed using the Manchester Scar Scale. A total of 8 lesions were treated. Temporary erythema and scar elevation were observed in 2 chest lesions; however, both were flattened and turned white using corticosteroid tape. Other than these 2 lesions, there was no recurrence or complication. The mean score improved from 15.8 to 7.2. The S-shaped wound closure technique has 3 advantages. First, no additional incision or excision is required, and additional scarring and keloid recurrence can be avoided. Second, aesthetic results are good, and noticeably long and zigzag-shaped scars can be avoided. Third, dispersion of tension on the scar can be expected. Although the S-shaped wound closure technique has limited application, it is a useful option for keloid treatment.

Plotting dermal sutures: An easy dermal suture technique

1 Hiroshi Matsumoto, MD Yoshihiro Kimata, MD, PhD Seiji Komatsu, MD, PhD Kumiko Matsumoto, MD Min Zaw Aung, MBBS, MMedSc (Surgery) Department of Plastic and Reconstructive Surgery Graduate School of Medicine, Dentistry, and Pharmaceutical Science University of Okayama Okayama, Japan Sir: W performing dermal sutures, we aim to achieve a satisfactory postoperative scar from an aesthetic perspective and reduce surgical site infection and other postoperative complications.1–3 Although the usefulness of dermal sutures is widely recognized, some residents and general surgeons are still reluctant to use dermal sutures due to concerns regarding the time needed to master this unfamiliar technique. Therefore, we designed a plotting dermal suture (PDS) method, which can be easily applied to appropriately perform dermal suturing. With this technique, we believe that even inexperienced surgeons can make dermal sutures in a quick and easy manner.

Modification of lattice structure and magnetic properties of Fe-Rh alloys by energetic electron irradiation

In order to modify the lattice structure and magnetic properties, we irradiate Fe-50at.%Rh alloys with 8 MeV electrons at room temperature. Effects of irradiation are investigated by using Superconducting QUantum Interference Device (SQUID) and X-Ray Diffractometer (XRD). Although the crystal structure is not changed by the irradiation and remains the B2 structure, the lattice parameter increases by about 0.1–0.3 % and the antiferromagnetic(AF)-ferromagnetic(FM) transition temperature decreases by 3–18 deg. with increasing the electron fluence. The present result shows that energetic electron irradiation can be used for the precise control of AF-FM transition temperature of Fe-50at.%Rh alloy.