Masaki Yazawa

Basic studies on the clinical applications of platelet-rich plasma.

Platelets, which contain many growth factors such as platelet-derived growth factor (PDGF) and transforming growth factor-β (TGF-β), are being used in clinical applications as platelet-rich plasma (PRP). Only a few studies, however, have been conducted on the growth factors present in PRP and on the clinical applications using the drug delivery system (DDS). For the purpose of clinical application, we first modified the PRP preparation method and assessed the amounts of growth factors contained in the human platelet concentrates. Furthermore, we assessed fibrin glue as a DDS of platelet concentrates. Platelet precipitations were made by twice centrifuging human whole blood. The precipitated platelet was resuspended to yield the platelet concentrates. The growth factor concentrations were measured. Fibrin glue sheets containing this platelet concentrate were implanted in rabbit pinna and samples were obtained for immunostaining (anti-PDGF antibody) to assess the use of PRP over time using the fibrin glue as the DDS. The mean concentration of growth factors present in the platelet concentrates was three times or greater than that of conventional PRP. Furthermore, the results indicated that when the platelet concentrate was used with fibrin glue as a carrier, the contents were released over a period of about 1 week. This raises the possibility that this system may be useful in clinical applications.

Basic studies on the bone formation ability by platelet rich plasma in rabbits

Purpose:Platelets, which contain many growth factors, such as platelet-derived growth factor (PDGF) and transforming growth factor-β (TGF-β), can be obtained in high concentrations by centrifugal separation and are being used as platelet-rich plasma (PRP) in clinical applications. The authors evaluated the bone formation ability by PRP in rabbits. Materials and Methods:In experiment 1, the authors made platelet precipitations from the whole blood obtained from rabbits. Each precipitated platelet was resuspended in fibrin glue. The glue was applied to a 1-mm wide slit defect of the same rabbit mandible. After 1 week, the authors observed the histologic appearances. In experiment 2, the fibrin glue containing the precipitated platelet was applied to a bicortical defect of a rabbit cranium with β-tricalcium phosphate (β-TCP) granules as artificial bone material. After 1 week, 1 month, and 2 months, the authors observed the radiologic and histologic appearances. Results and Conclusions:In both experiments, a prosperous bone formation was observed from the beginning more in the group treated with PRP than in the group untreated. In experiment 2, gradual appearances of the bone formation were observed in the bubble of β-TCP. In application with artificial bone materials, bone formations by PRP were suitably observed.

Stem cell self-renewal factors Bmi1 and HMGA2 in head and neck squamous cell carcinoma: clues for diagnosis

Head and neck squamous cell carcinoma (HNSCC) includes both morphological and functional cellular heterogeneity, as would be expected if it arose from dysregulated stem or progenitor cells as opposed to the simple clonal expansion of a mutated cell; however, stemness molecule expression levels and distribution in HNSCC remain unclear. To clarify this, stemness molecule expressions were determined in HNSCC, as well as their properties and prognosis. Two proto-oncogenic chromatin regulators, Bmi-1 and high-mobility-group A2 (Hmga2), were identified in 12 pair cases of HNSCC tumor regions by comparison with their non-cancerous background tissues using cDNA microarray. Both Bmi-1 and Hmga2 are known to promote stem cell self-renewal by negatively regulating the expressions of Ink4a and Arf tumor suppressors. Despite similar targets, Bmi-1 protein was expressed in an early cancerous region and HMGA2 protein was expressed in a region showing more progression. Similarly, Bmi1 expression had no significance with regard to overall survival (P=0.67), whereas HMGA2 expression was associated with decreased overall survival (P=0.05). Quantitative real-time reverse transcription polymerase chain reaction analyses also correlated with protein levels. These findings suggest that Bmi-1 is an early detection marker to distinguish cancerous from non-cancerous regions, whereas HMGA2 is presumed to be a tumor prognosis marker. Among our HNSCC analyses, these stemness molecules expressed fewer primitive rare cells in the tumor than all other cells in the tumor. HNSCC cells with high expression of stemness molecules partly behave like stem cells.

Evaluation of Bone Volume After Secondary Bone Grafting in Unilateral Alveolar Cleft Using Computer-Aided Engineering

The purpose of this study was to evaluate the initial defect and the outcome of bone grafts for unilateral alveolar cleft. To determine the absorption of the bone graft in patients with unilateral cleft, computer-aided engineering (CAE) with multi-detector row computed tomography (MDCT) was used. MDCT scans of 29 patients were taken immediately preoperatively and at 1 month and 6 months postoperatively. The patients underwent bone grafting between 8 and 14 years of age using iliac crest bone grafts. Three-dimensional models were created in each period, and the defect at the alveolar cleft and volume of the bone graft were determined in each patient using CAE. Cleft volume and success of alveolar bone grafting were significantly correlated (P < .01). Alveolar clefts with cleft palate required more bone volume than those without cleft palate (P < .01), but the resorption rate did not significantly differ between alveolar clefts with and without cleft palate (0.48 ± 0.14 and 0.49 ± 0.18, respectively; P =.93). In conclusion, three-dimensional reconstruction of bone grafts using CAE based on MDCT provides a valuable objective assessment of graft volume.

Primary dural closure and anterior cranial base reconstruction using pericranial and nasoseptal multi-layered flaps in endoscopic-assisted skull base surgery

IntroductionDural and anterior cranial base reconstruction is essential in the surgical resection of a craniofacial tumor that extends from the paranasal sinuses to the subdural space. Watertight reconstruction of vascularized tissue is essential to prevent postoperative liquorrhea, especially under conditions that prevent wound healing (e.g., postoperative irradiation therapy).MethodWe successfully treated two cases of olfactory neuroblastoma by endoscopic-assisted craniotomy with primary dural closure and anterior cranial base reconstruction using a multi-layered flap technique. Dural defects were closed using temporal fascia or fascia lata in a conventional fashion, immediately after detaching the subdural tumor, in order to isolate and prevent contamination of subdural components and cerebrospinal fluid (CSF) from the tumor and nasal sinuses. Tumor removal and anterior cranial base reconstruction were performed without any concern of CSF contamination after dural closure by craniotomy and endoscopic endonasal approach (EEA). Vascularized pericranial flaps (PCF) and nasoseptal flaps (NSF) were used simultaneously as doubled-over layers for reconstruction.ResultsThe tumor was completely removed macroscopically and the anterior cranial base was reconstructed in both cases. CSF leak and postoperative meningitis were absent. Postoperative and irradiation therapy courses were successful and uneventful.ConclusionsThis multi-layered anterior cranial base reconstruction consisted of three layers: a fascia for dural plasty and double-layered PCF and NSF. This surgical reconstruction technique is suitable to treat craniofacial tumors extending into the subdural space through the anterior cranial base dura mater.

Influence of vascularized transplant bed on fat grafting

Recent advances in regenerative medicine have opened up the option of materials used for transplantation. However, only a few studies have examined the take of transplanted tissues. We attempted to establish a functional bed for transplanted tissues using growth factors. A cylinder‐type silicone substrate (spacer) was coated with a photoreactive gelatin containing basic fibroblast growth factor. This spacer was transplanted into the dorsal subdermal layer in a rabbit. After 2 and 4 weeks, the capsule formed around the spacer was histologically assessed for use as a transplant bed. In addition, after 2–4 weeks of spacer grafting, autologous fat was transplanted into the capsule. After 4 more weeks, the grafted fat was assessed immunohistochemically to evaluate the capsule as a functional bed for transplantation. In the groups pretreated with growth factors, proliferation of blood vessels was observed in the capsules. After fat grafting, a pattern of overall necrosis was observed in controls. However, good proliferation of blood vessels and favorable fat take were observed in the groups pretreated with growth factors. Necrosis, however, was found at the center of the grafted fat. We conclude that a vascularized transplant bed was useful for promoting take of the grafted fat.

Is surgical intervention safe and effective in the treatment of myasthenic blepharoptosis? A multicenter survey in Japan

neurological centers constituting the Japan MG Registry Study Group. All of the patients were interviewed about the clinical features of their MG and whether they had undergone blepharoptosis surgery. A total of 19 patients (2.8%; 7 men, 12 women; mean age: 65.7 years) had undergone blepharoptosis surgery, and were further evaluated by using a questionnaire. Questions regarding the timing of the surgery (relative to MG onset), the ease of eyelid opening [over both the short term ( ≤ 1 year) and long term (>1 year), postoperatively], aesthetic outcome (scarring), overall satisfaction with the surgery, and any noted complications. Three-point Likert scales were used to assess the ease of eyelid opening (much easier, easier, worse), scarring (very minimal, minimal, visible), and overall satisfaction with the surgery (very satisfied, satisfied, dissatisfied). To evaluate scarring, the patients answered the questionnaires with their attending neurologists in the out-patient clinics. The actual surgeons were not present to help in obtaining unbiased opinions from the patients. All clinical information was collected after the patients had provided written Dear Sir, Myasthenia gravis (MG) is an antibodymediated, neuromuscular transmission disorder. Its clinical manifestations range from ocular myasthenia, which can be visually disabling, to myasthenic crisis, with patients experiencing life-threatening respiratory insufficiencies [1] . Several effective medical treatments are available for the ocular symptoms of MG [2–6] ; however, physicians often struggle to treat patients with longstanding blepharoptosis [7–9] . Moreover, although blepharoptosis surgery is occasionally applied in such cases [10, 11] , the indications and clinical effectiveness of blepharoptosis surgery for MG patients remains unclear. In the present study, we retrospectively investigated the clinical features of blepharoptosis surgery by interviewing 19 Japanese patients with MG.

Surgical creation of a Cupid's bow using W-plasty in patients after cleft lip surgery

The three-dimensional contour of the Cupids bow is extremely important from a cosmetic standpoint, and many patients with bilateral or unilateral cleft lip require revision or reconstruction of the Cupids bow.A number of surgical techniques have been reported for creating the Cupids bow, among which the methods of Gillies and Onizuka are the most widely known. In the methods of Gillies and Onizuka, the dog-ear can result in excessive volume in the vermilion notch, raising the trough in the Cupids bow and leading to regression during the post-surgical period. We have improved upon these techniques using the W-plasty and have obtained satisfactory results that preserve the white skin roll. In our method, the left and right prominence of the Cupids bow is created through an incision of the white lip, while the central trough is created through a curvilinear incision of the vermilion mucosa. At the two sites of the white lip tissue and the curvilinear incision of the central vermilion tissue, the white skin roll is preserved as much as possible. In patients where the Gillies method had been used, the Cupids bow tended to be flattened gradually after surgery. We report on the details of our method and the case reports using the technique.

Surgical treatment for medically refractory myasthenic blepharoptosis

Purpose Currently, only a few reports have recommended surgery as a suitable treatment for blepharoptosis associated with myasthenia gravis. The present study aims to introduce our surgical criteria, surgical options, outcomes, and precautions for medically refractory myasthenic blepharoptosis. Patients and methods Eight patients who failed to respond to at least 2 years of medical treatment and who underwent blepharoptosis surgery, from January 2008 to December 2011, were enrolled in this study. Medical records, photographs, and questionnaire results regarding postoperative status were evaluated. Of the eleven procedures performed, four involved frontal suspension, four involved external levator advancement, one involved nonincisional transconjunctival levator advancement, and two involved subbrow blepharoplasty with orbicularis oculi muscle tucking. The margin reflex distance improved postoperatively in seven patients. Results Seven patients had very minimal scarring, and one had minimal scarring. Five patients showed no eyelid asymmetry, one had subtle asymmetry, and two had obvious asymmetry. Seven patients were very satisfied, and one patient was satisfied with the overall result. Postoperative complications included mild lid lag with incomplete eyelid closure, prolonged scar redness, and worsened heterophoria. No patient experienced postoperative exposure keratitis or recurrent blepharoptosis during the study period. Conclusion Our results indicate that blepharoptosis surgery is effective for patients with myasthenia gravis, especially those with residual blepharoptosis despite multiple sessions of medical treatments. We recommend that neurologists and surgeons collaborate more systematically and discuss comprehensive treatment plans to increase the quality of life for patients with myasthenia gravis.

Usefulness of Choline-PET for the detection of residual hemangiopericytoma in the skull base: comparison with FDG-PET

BackgroundCholine is a new PET tracer that is useful for the detection of malignant tumor. Choline is a precursor of the biosynthesis of phosphatidylcholine, a major phospholipid in the cell membrane of eukaryotic cells. Malignant tumors have an elevated level of phosphatidylcholine in cell membrane. Thus, choline is a marker of tumor malignancy.MethodThe patient was a 51-year-old man with repeated recurrent hemangiopericytoma in the skull base. We performed Choline-PET in this patient after various treatments and compared findings with those of FDG-PET.ResultsCholine accumulated in this tumor, but FDG did not accumulate. We diagnosed this tumor as residual hemangiopericytoma and performed the resection of the residual tumor. FDG-PET is not appropriate for skull base tumor detection because uptake in the brain is very strong.ConclusionWe emphasize the usefulness of Choline-PET for the detection of residual hemangiopericytoma in the skull base after various treatments, compared with FDG-PET.