Yasuyuki Hiratsuka

Regeneration of the vocal fold using autologous mesenchymal stem cells

The aim of this study was to regenerate the injured vocal fold by means of selective cultured autologous mesenchymal stem cells (MSCs). Eight adult beagle dogs were used for this experiment. Selective incubation of MSCs from bone marrow was done. These MSCs were submitted to 3-dimensional incubation in 1% hydrochloric acid atelocollagen. Three-dimensional incubated MSCs were injected into the left vocal fold, and atelocollagen only was injected into the right vocal fold of the same dog as a control. Four days after injection, the posterior parts of the vocal folds were incised. The regeneration of the vocal fold was estimated by morphological and histologic evaluations. Our results showed that 3-dimensional incubated MSCs were useful in the regeneration of the injured vocal fold. This study shows that damaged tissues such as an injured vocal fold would be able to be regenerated by tissue engineering.

Transplantation of bone marrow stromal cells into the cochlea of chinchillas.

This study aimed to evaluate the potential of bone marrow stromal cells for treatment of inner ear diseases. Autologous marrow cells labeled with DiI were implanted into the inner ear of five gentamicin-treated chinchillas. Histological analysis 3 weeks later revealed robust survival of grafted marrow cells in multiple regions within the cochlea. Marrow cells implanted in the basal turn of the cochlea migrated as far as the apical end or into the spiral ligament of the cochlea. Some grafted cells expressed a neuronal or glial cell marker, indicating their ability to differentiate into neuronal or glial cells. Survival, migrational mobility and differentiation of autologous marrow cells in damaged cochlea suggest their potential as transplants for treatment of various degenerative inner ear diseases.

Basic fibroblast growth factor combined with atelocollagen for closing chronic tympanic membrane perforations in 87 patients.

Objective: To present the clinical results of closing chronic tympanic membrane (TM) perforations using basic fibroblast growth factor (bFGF) combined with an atelocollagen/silicone bilayer membrane patch. Study Design: Closure of TM perforations in 87 patients was attempted using bFGF, which is thought to promote the regeneration of TM tissues by facilitating the growth of fibroblasts and collagen fibers. Methods: Under an operating microscope, the margin of the perforation was trimmed, and a piece of an atelocollagen/silicone bilayer membrane was placed in the perforation with the silicon layer facing outward and then infiltrated with 0.1 ml of trafermin. Data obtained from patient records included patient age, perforation size, and duration of treatment, with a focus on hearing improvement and complete TM closure. Results: The mean perforation size before treatment was 14.4%. Complete closure of the TM perforation was achieved in 80 patients (92.0%), whereas pinholes remained in 5 patients (8.7%), and small perforations were observed in 2 patients (2.3%). In the patients with complete closure, the TM perforations closed after an average 1.8 treatments, and hearing improved by 13.6 dB. Conclusion: This study demonstrated that bFGF combined with atelocollagen is effective for the conservative treatment of TM perforation.

Recurrent laryngeal nerve regeneration by tissue engineering

The recurrent laryngeal nerve (RLN) does not regenerate well after it has been cut, and no current surgical methods achieve functional regeneration. Here, we evaluate the functional regeneration of the RLN after reconstruction using a biodegradable nerve conduit or an autologous nerve graft. The nerve conduit was made of a polyglycolic acid (PGA) tube coated with collagen. A 10-mm gap in the resected nerve was bridged by a PGA tube in 6 adult beagle dogs (group 1) and by an autologous nerve graft in 3 dogs (group 2). Fiberscopic observation revealed functional regeneration of the RLN in 4 of the 6 dogs in group 1. No regeneration of the RLN was observed in any dog in group 2. We also tested for axonal transport, and measured the compound muscle action potential. The RLN can be functionally regenerated with a PGA tube, which may act as a scaffold for the growth of regenerating axons.

Cricoid Regeneration Using in Situ Tissue Engineering in Canine Larynx for the Treatment of Subglottic Stenosis

The purpose of the present study was to evaluate the efficacy of cricoid regeneration via in situ tissue engineering in a canine larynx for the treatment of subglottic stenosis. As the tissue scaffold, a Marlex mesh tube coated by collagen sponge was used for a rigid airway framework and for tissue regrowth around the tube. On 5 dogs, the larynx was exposed and the anterior third of the cricoid cartilage was resected. The tube was anastomosed to the lower edge of the thyroid cartilage and to the first tracheal cartilage. By postoperative endoscopic examination at 3 to 7 months, no airway obstruction was observed in any of the dogs. There was granulation tissue in 2 dogs and slight mesh exposure in 1 dog, but they were asymptomatic. Confluent regeneration of the epithelium over the scaffold and good incorporation of the scaffold mesh into the host tissue were observed after surgery.

Negative-pressure pulmonary edema after resection of mediastinum thyroid goiter.

Negative-pressure pulmonary edema (NPPE) is an uncommon but life-threatening complication of acute or chronic upper airway obstruction; however, there are few reports of NPPE after giant goiter resection. We report a case with severe NPPE induced by the resection of a mediastinum thyroid goiter. The patient was successfully treated by non-invasive positive airway ventilation (NPPV).

Nerve‐Muscle Transplantation to the Paraglottic Space after Resection of Recurrent Laryngeal Nerve

Objective: To evaluate a new method of nerve‐muscle transplantation (NMT) to the paraglottic space after resection of the recurrent laryngeal nerve (RLN) during surgery for thyroid cancer.

Association of chromium exposure with multiple primary cancers in the nasal cavity.

A 56-year-old man who had worked at a chromate factory for 13 years developed squamous cell carcinoma of the left nasal cavity 11 years after retirement. He received intra-arterial chemotherapy, followed by surgery. Two years later, an adenocarcinoma was identified in the same nasal cavity just above the previous surgical region. He underwent medial maxillectomy in combination with postoperative irradiation. He has been disease free for 5 years after the second surgery. Microsatellite markers were examined in the second tumor specimen as a possible factor for carcinogenesis; however, replication errors were not observed in any of four loci (D2S123, D3S1067, TP53, D18S474) tested. The present case seems to have resulted from long-term exposure to chromium and, to our knowledge, is the first reported case with multiple primary cancers in the nasal cavity associated with chromium exposure.

Clinical Study of Surgically Treated Cases of Primary Hyperparathyroidism.

Thirty patients with primary hyperparathyroidism (PHPT), who were all surgically treated with a parathyroidectomy, were retrospectively studied. Ultrasonography was the most useful preoperative imaging. Pathological findings revealed 28 adenomas, 1 hyperplasia, and 1 carcinoma. In all cases, only one swollen gland was removed, and values of serum calcium and parathyroid hormone were normalized after surgical treatment. There were no significant postoperative problems. The suggested treatment for PHPT is the extirpation of one swollen gland, which is detected with preoperative imagings.

Maxillary Sinus Mucoceles without a History of Surgery or Trauma.

Maxillary sinus mucoceles without a history of previous surgery or trauma are extremely rare. If these mucoceles are accompanied by bony destruction, then the differential diagnosis includes tumorous lesions. We report here two such cases of maxillary sinus mucoceles. In both cases, a CT scan showed a homogeneous mass causing expansion of the maxillary sinuses and bony destruction. Aspiration from the affected maxillary sinuses showed a thick yellowish fluid, which suggested that they were mucoceles. The findings of the Caldwell-Luc operation with an antrostomy coincide with the diagnosis of mucoceles, and no further tumorous lesions were observed by histological examination.