Efficient cell transplantation combining injectable hydrogels with control release of growth factors.

INTRODUCTION: The objective of this study is to investigate the effect of gelatin microspheres incorporating growth factors on the therapeutic efficacy in cell transplantation. The strength of this study is to combine gelatin hydrogel microspheres incorporating basic fibroblast growth factor and platelet growth factor mixture (GM/GF) with bioabsorbable injectable hydrogels (iGel) for transplantation of adipose-derived stem cells (ASCs). METHODS: The rats ASCs suspended in various solutions were transplanted in masseter muscle. Rats were euthanized 2, 7, 14 days after injection for measurement of the number of ASCs retention in the muscle and morphological evaluation of muscle fibers and the inflammation of the injected tissue by histologic and immunofluorescent stain. RESULTS: Following the injection into the skeletal muscle, the GM/GF allowed the growth factors to release at the injection site over one week. When ASCs were transplanted into skeletal muscle using iGel incorporating GM/GF (iGel+GM/GF), the number of cells grafted was significantly high compared with other control groups. Moreover, for the groups to which GM/GF was added, the cells transplanted survived, and the Myo-D expression of a myoblast marker was observed at the region of cells transplanted. CONCLUSIONS: The growth factors released for a long time likely enhance the proliferative and differentiative capacity of cells. The simple combination with iGel and GM/GF allowed ASCs to enhance their survival at the injected site and consequently achieve improved therapeutic efficacy in cell transplantation.

Endoscopic soft palate augmentation using injectable materials in dogs to ameliorate velopharyngeal insufficiency.

BACKGROUND: Velopharyngeal structure augmentation methods are used as alternatives to pharyngeal flap operations. Recently, we investigated the sites of velopharyngeal structure augmentation in dogs and reported that the most effective injection location is the soft palate. However, there have been no reports regarding the optimal materials for implantation or injection. In this study, we aimed to investigate the injectable materials used in soft palate augmentation in dogs to ameliorate velopharyngeal insufficiency (VPI). METHODS: Endoscopic soft palate augmentation (ESPA) was performed in dogs using purified sodium hyaluronate, atelocollagen, or autogenic fat tissue. ESPA is an original technique developed by our group, and this is the first report of its performance. Moreover, we assessed the amount of nasal air leakage during inspiration at rest and during expiration under the rebreathing system at 1, 2, 3, 4, 5, and 6 months after injection of these materials. RESULTS: The amount of nasal air leakage during expiration under the rebreathing system was significantly decreased in all dogs injected with the ESPA materials, but neither apnea nor hypopnea was observed. CONCLUSIONS: We investigated the optimal materials for use in ESPA, such as purified sodium hyaluronate, atelocollagen, or autogenic fat tissue. We found that all of them reduced nasal air leakage and only autogenic fat tissue showed significant histologic differences in dogs at 6 months. This technique may also be useful for the treatment of patients with VPI.

The Behaviors of the Levator Veli Palatine Muscle Between 2 Surgical Conditions in Dog: The Comparison of Furlow and Pushback Methods.

OBJECTIVE: This study was conducted to compare the velopharyngeal function among the beagle dogs which the levator veli palatini (LVP) muscles construction has been experimentally changed. METHODS: Four groups of LVP muscle reconstruction were made (normal LVP, cut LVP, end-to-end sutured LVP, and overlapped-sutured LVP at the midline). Levator veli palatini contraction was induced by electrical stimulation or a hypercapnia condition to analyze the strength of the velopharyngeal closure using balloon with a blood pressure meter, and the electromyogram in those operated beagle dogs. RESULTS: Under a hypercapnia condition, the velopharyngeal function did not differ significantly among the 4 groups in the terms of velopharyngeal pressure. The strongest closure was shown at the overlapped sutured LVP group by electrical stimulation. CONCLUSION: The reconstruction of overlapped sutured LVP showed the most effective closure. This study suggested that the palatoplasty should be conducted along the overlapped LVP (like Furlow method).

Hemi-tongue Allograft Transplantation in Dogs.

BACKGROUND: When complete recovery of tongue function following tumor excision is desired, reestablishment of the complex movements of the tongue is necessary. However, currently available methods for recovery of tongue function, such as flap surgery or prosthesis insertion, are inadequate. In the current study, we investigated the effects of transplantations of tongue allografts. METHODS: Hemi-tongue allotransplantation procedures were performed with 8 pairs of sex-blind and unrelated beagle dogs. In each donor, the right side of the tongue, including the lingual and hypoglossal nerves, extrinsic muscles of the tongue, mucous membrane of the oral floor, lingual artery, and vein were exposed. A vascularized transplantation method was used with manual anastomosis of the blood vessels and nerves. RESULTS: Survival of the grafted tongue was only noted in 1 dog that died 5 days after transplantation. We suspected that the death was due to nutritional deficiency or dehydration, rather than hyperacute rejection of the transplant or technical failure of the microsurgical anastomosis. The grafted tongue was partially connected to the side of the recipient tongue, and lymphocyte infiltration was observed in this dog. CONCLUSIONS: Postoperative management is difficult in dogs. Even if tongue allograft including nerves and extrinsic muscles is performed, it seems to take a long time before the tongue recovers its functions. Furthermore, expansive tongue allograft was too invasive a treatment for animals. If we want to adapt this procedure to humans, the first trial in a human will be done without animal experiments, as was the case with face transplantations.

Ion chromatography for determination of nitrite and nitrate in seawater using monolithic ODS columns.

A fast and highly sensitive ion chromatographic method using monolithic ODS columns was developed for the determination of nitrite (NO2-) and nitrate (NO3-) in seawater. Two monolithic ODS columns (50 mm x 4.6 mm i.d. + 100 mm x 4.6 mm i.d.) connected in series were coated and equilibrated with 5 mM cetyltrimethylammonium chloride (CTAC) aqueous solution. The column efficiency with 0.5 M NaCl as the mobile phase did not decrease in spite of the increase in flow rate of the mobile phase. Thus, good chromatograms were obtained within 3 minutes for NO2- and NO3 in artificial seawater without interferences by coexisting ions. The detection limit (S/N = 3) with UV detection at 225 nm was 0.8 and 1.6 microg/L for NO2- and NO3-, respectively. The characteristics of the monolithic CTA(+)-coated ODS columns were discussed. The present method was successfully applied to the fast and sensitive determination of NO2- and NO3- in real seawater samples.