Publications by authors named "Hidekazu Yoshizawa"

Background: Oncoplastic lower eyelid reconstruction is a challenging task due to the complicated structure of the eyelid and requirement of high operative accuracy. Poorly treated defects result in ectropion and ptosis which may lead to keratitis and corneal ulceration. Previous related studies do not include a detailed comparison of the common reconstructive methods of the lower eyelid in terms of results and complication rates.

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Purpose: Diffusional kurtosis imaging (DKI) enables sensitive measurement of tissue microstructure by quantifying the non-Gaussian diffusion of water. Although DKI is widely applied in many situations, histological correlation with DKI analysis is lacking. The purpose of this study was to determine the relationship between DKI metrics and neurite density measured using confocal microscopy of a cleared mouse brain.

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Axonal regeneration relies on support from proliferating host Schwann cells (SCs), and previous studies on acellular nerve allografts (ANGs) suggest that axons can regenerate into ANGs within a limited distance. Numerous studies have demonstrated that the supplementation of ANGs with exogenous factors, such as cultured SCs, stem cells, and growth factors, promote nerve regeneration in ANGs. However, there are several problems associated with their utilization.

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Background: Losing the ability to speak severely affects the quality of life, and patients who have undergone laryngectomy tend to become depressed, which may lead to social withdrawal. Recently, with advancements in chemoradiotherapy and with alternative perspectives on postoperative quality of life, larynx preservation has been pursued; however, the selection of candidates and the optimal reconstructive procedure remain controversial. In this study, we retrospectively reviewed our experience with free jejunal graft for larynx-preserving cervical esophagectomy (LPCE), focusing on microvascular reconstruction.

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Introduction: Lid loading using gold weights has been commonly used to treat paralytic lagophthalmos (PL); however, the procedure has a relatively high complication rate and the availability of these plates varies among social circumstances. We used a levator lengthening (LL) technique, which originally elongated the levator aponeurosis by inserting a fascia graft between the edge of the levator aponeurosis and the tarsal plate. However, because this procedure tends to result in a wide residual lagophthalmos, we changed the graft material from fascia to conchal cartilage.

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Background: Frey syndrome (FS) or depressive deformity (DD) occurring after parotidectomy significantly reduces a patient's quality of life. However, there seems to be no effective treatment strategy against these complications. In this study, we report our experience of using platysma muscle flap (PMF) to prevent the development of FS and DD after parotidectomy, and evaluate its effect subjectively and objectively.

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Introduction: There are two main methods to treat lower-lip deformity (LLD) in facial paralysis. The first method is surgical intervention on the side of the paralysis, and the second involves denervating the depressor muscles on the healthy side. It is sometimes difficult for patients to ethically accept the denervating healthy tissue; therefore, we performed the T-shape double fascia graft (TSDFG), which reportedly restores symmetry.

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During surgery, peripheral nerves are often seen to follow unpredictable paths because of previous surgeries and/or compression caused by a tumor. Iatrogenic nerve injury is a serious complication that must be avoided, and preoperative evaluation of nerve paths is important for preventing it. In this study, transcutaneous electrical nerve stimulation (TENS) was used for an in-depth analysis of peripheral nerve paths.

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Soft tissue defects or skin ulcers associated with tendon or bone exposure located distally on the extremities are always difficult to treat. The introduction of the vacuum-assisted closure (VAC) and dermal templates has led to major changes in ulcer treatment strategies. However, it is necessary to find an alternative method to treat these defects when VAC is not available.

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Article Synopsis
  • Myoepithelial carcinoma is a rare type of tumor mainly found in major salivary glands and can be challenging to identify as benign or malignant due to varied clinical behaviors and histological features.
  • A case study of a 55-year-old woman highlights the significant size of her myoepithelial carcinoma (10.5 kg), which she avoided treating for 3 years, raising the initial consideration for neoadjuvant therapy before surgery.
  • After careful evaluation of the tumor's low-grade characteristics, the surgical team opted for excision, successfully reconstructing the skin defect using adjacent tissue without further complications, and the patient has remained free of recurrence or metastasis for 2 years.
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Distally based radial artery perforator flap (DBRAPF) is useful for hand defects; however, the location of the perforator varies among individuals. Preoperative evaluation has been a problematic issue when performing this flap. A 64-year-old man developed squamous cell carcinoma on an old burn scar at the dorsal thumb and was referred to our clinic for further treatment.

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Lengthening temporalis myoplasty, reported by Daniel Labbé in 1997, is a unique and definite facial reanimation procedure that involves moving the whole temporal muscle anteroinferiorly and inserting its tendon directly into the nasolabial fold. In the present article, we report our experience in the use of his modified method of the procedure, which preserves the zygomatic arch by transecting the coronoid process through the nasolabial fold incision. We also describe our cadaveric study that aimed to elucidate a secure approach for coronoid process transection.

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Our previous research showed that poly(vinyl alcohol) (PVA) nanoparticles incorporating DNA with hydrogen bonds obtained by high hydrostatic pressurization are able to deliver DNA without any significant cytotoxicity. To enhance transfection efficiency of PVA/DNA nanoparticles, we describe a novel method to prepare PVA/DNA nanoparticles encapsulating nanoscaled hydroxyapatites (HAps) prepared by high hydrostatic pressurization (980 MPa), which is designed to facilitate endosomal escape induced by dissolving HAps in an endosome. Scanning electron microscopic observation and dynamic light scattering measurement revealed that HAps were significantly encapsulated in PVA/HAp/DNA nanoparticles.

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A novel micromixer with simple construction and excellent mixing performance is developed. The micromixer is composed of two stainless steel tubes with different diameters: one is an outer tube and another is an inner tube which fits in the outer tube. In this micromixer, one reactant fluid flows in the mixing zone from the inner tube and the other flows from the outer tube.

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We demonstrate a simple, unique method for preparing microcapsules with holes in their shells. Cross-linked polymelamine microcapsules are prepared by the phase-separation method. The holey shell of each microcapsule is synthesized on the surface of an oil-in-water (O/W) emulsion droplet where a water-soluble polymeric surfactant and an oil-soluble surfactant are competitively adsorbed.

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In order to investigate the effect of pressure on the tertiary structure of plasmid DNA having the supercoiled and relaxed forms, the solution of plasmid DNA was hydrostatically pressurized at different atmosphere and 40 degrees C for various times. For dynamic light scattering (DLS) measurement of the pressurized plasmid DNA, the hydrodynamic diameters of the super-coiled and relaxed plasmid DNA were decreased with increasing pressure. Also, at constant pressure, a long period of pressure treatment effectively induced the decrease in plasmid DNA.

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Poly(vinyl alcohol) (PVA) hydrogels interacting with DNA mediated by hydrogen bonds (PVA/DNA hydrogel) were developed using ultra-high pressure (UHP) technology. The goal was to create a new method of gene delivery by controlled release of DNA. Mixed solutions of DNA and PVA at various concentrations were pressurized at 10,000 atmospheres at 37 degrees C for 10 min.

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Various water-soluble polymers were used to examine an alternative emulsifier for poly(ethylene-alt-maleic anhydride), used in the preparation of crosslinked polyurea microcapsules. Microcapsules were successfully prepared by using the water-soluble polymers with large molecular weight alternating copolymers, namely poly(olefin-maleic anhydride), poly(olefin-maleic acid), and poly(acrylic acid). On the other hand, no microcapsule resulted from olefin-maleic acid with small molecular weight alternating copolymers.

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We introduced newly biodegradable polymer surfactant to poly(D,L-lactide) microspheres for exhibiting precisely controlled release rate of antitumor agent. We newly designed biodegradable polymer surfactant, poly(ethyleneoxide monooleate)-block-poly(D,L-lactide); (MOPEO-PLA), which has a biocompatible, oil-soluble and compatible with polylactide matrices. Polylactide (PLA) microspheres with MOPEO-PLA enclosing Irinotecan hydrochloride (CPT-11) was successfully fabricated by solvent evaporation method via O/O emulsion.

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In this paper, we report a novel synthesis of poly(ethylene oxide monooleate-block-DL-lactide) (MOPEO-PLA) in the presence of stannous 2-ethylhexanoate catalyst. By utilizing the surfactant property and the reactive double bond of the amphiphilic MOPEO-PLA, various characteristics of PLA microspheres, such as surface and internal structure, surface morphology, release property, and so on, may potentially be controlled. MOPEO-PLA was found to be hydrophobic enough to prevent loss by dissolution into aqueous solution, which is often a problem for MOPEO.

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In order to reduce the initial burst from polylactide (PLA) microspheres enclosing an antitumor agent, we prepared the microspheres with a smooth surface by varying solvent evaporation conditions such as operating temperature and pressure. PLA microspheres enclosing irinotecan hydrochloride (CPT) were prepared using the O/O emulsion system for solvent evaporation. The mean diameter and enclosing efficiency were almost constant because they were independent of solvent evaporation conditions.

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