Yasutoshi Suzuki

The mechanism of epidermal hyperpigmentation in café-au-lait macules of neurofibromatosis type 1 (von Recklinghausen's disease) may be associated with dermal fibroblast-derived stem cell factor and hepatocyte growth factor

Summary Background The mechanism of the accentuated melanization in café‐au‐lait macules (CALMs) in patients with neurofibromatosis type 1 (NF1; von Recklinghausens disease) has not been elucidated.

Effects of all-trans retinoic acid on melanogenesis in pigmented skin equivalents and monolayer culture of melanocytes

The effects of all-trans retinoic acid (RA) on melanogenesis and the mechanism of its action in topical treatment have not been elucidated. The purpose of this study was to determine the effects of RA on melanogenesis in the pigmented skin equivalent as well as in monolayer culture of melanocytes, and to determine whether RA, hydroquinone (HQ), and hydrocortisone (HC) show synergistic depigmenting effects in combined treatments of each other. The suppressing effect of RA on melanogenesis was not observed in pigmented skin equivalents and monolayer culture of murine and human melanocytes, although HQ showed strong inhibition of melanogenesis. The synergistic effects between RA, HQ, and HC were not particularly seen. The results suggested that RA neither has direct inhibitory effects on melanogenesis of melanocytes, nor influences the cell-cell interactions between melanocytes, keratinocytes and fibroblasts, such as paracrine actions with regard to melanin production. The role of RA in bleaching treatments appears to be in other specific actions, such as promotion of keratinocytes proliferation and acceleration of epidermal turnover.

Effects of subepithelial fibroblasts on epithelial differentiation in human skin and oral mucosa: heterotypically recombined organotypic culture model.

The stratified squamous epithelia differ regionally in their patterns of morphogenesis and differentiation. Although some reports suggested that the adult epithelial phenotype is an intrinsic property of the epithelium, there is increasing evidence that subepithelial connective tissue can modify the phenotypic expression of the epithelium. The aim of this study was to elucidate whether the differentiation of cutaneous and oral epithelia is influenced by underlying mesenchymal tissues. Three normal skin samples and three normal buccal mucosa samples were used for the experiments. Skin equivalents were constructed in four ways, depending on the combinations of keratinocytes (cutaneous or mucosal keratinocytes) and fibroblasts (dermal or mucosal fibroblasts), and the effects of subepithelial fibroblasts on the differentiation of oral and cutaneous keratinocytes were studied with histological examinations and immunohistochemical analyses with anti-cytokeratin (keratins 10 and 13) antibodies. For each experiment, three paired skin equivalents were constructed by using single parent keratinocyte and fibroblast sources for each group; consequently, nine (3 × 3) organotypic cultures per group were constructed and studied. The oral and cutaneous epithelial cells maintained their intrinsic keratin expression. The keratin expression patterns in oral and cutaneous epithelia of skin equivalents were generally similar to their original patterns but were partly modified exogenously by the topologically different fibroblasts. The mucosal keratinocytes were more differentiated and expressed keratin 10 when cocultured with dermal fibroblasts, and the expression patterns of keratin 13 in cutaneous keratinocytes cocultured with mucosal fibroblasts were different from those in keratinocytes cocultured with cutaneous fibroblasts. The results suggested that the epithelial phenotype and keratin expression could be extrinsically modified by mesenchymal fibroblasts. In epithelial differentiation, however, the intrinsic control by epithelial cells may still be stronger than extrinsic regulation by mesenchymal fibroblasts.

Comparison of bacteria-retaining ability of absorbent wound dressings

Fibrous materials in some modern absorbent wound dressings have the ability to sequester and retain bacteria; however, this ability varies according to the nature of the fibres. We studied the bacterial retention capacity of alginate and carboxymethylcellulose dressings, using an infected skin ulcer model on the backs of rats. Wound surfaces were inoculated with either Staphylococcus aureus or Pseudomonas aeruginosa at a concentration of 1·5 × 106 colony‐forming units per wound. AQUACEL®; Hydrofiber®;, Kaltostat®; or Sorbsan®; were applied to the contaminated wounds for 12 h. Each dressing was then divided into two pieces. Total viable bacterial count within the dressing was calculated using one piece, and bacterial count released from the dressing into physiological saline was determined using the other piece, enabling bacterial retention rate to be calculated. Bacterial counts in tissue were also determined. Each dressing was tested on each of 10 wounds contaminated with each bacterium. Statistical analyses were performed using one‐way analysis of variance (ANOVA) for replicated measures combined with Duncans multiple comparison test. AQUACEL®; Hydrofiber®; dressing was most effective in its ability to retain both Staphylococcus aureus and Pseudomonas aeruginosa (p < 0·05). Bacterial counts in tissue showed no significant change with respect to pathogen or the type of dressing used. It can be concluded that the bacterial retaining ability of AQUACEL®; Hydrofiber®; dressing was found to be significantly higher than that of alginate dressings in an infected animal wound model.

Blood Gas Analysis of the Jejunum in the Supercharge Technique: To What Degree Does Circulation Improve?

Background: The supercharge technique has become widely prevalent in the field of esophageal reconstruction. Despite the logical advantages with this technique, the actual degree of its effect on the blood circulation is not clear. There may be cases in which the supercharge technique is not necessary for survival of the jejunum. To decide whether or not the supercharge technique is indicated, it is crucial to know how effective it is in improving blood flow to the jejunum. Methods: The effect of the additional vessel anastomosis in the pedicled jejunal transfer was evaluated by blood gas analysis of the venous blood in the mesenteric vein. In 27 patients undergoing pedicled jejunal transfer with additional vessel anastomosis using the internal mammary vessels for reconstruction of the thoracic esophagus, intraoperative blood sampling was performed three times: before anastomosis, after venous anastomosis, and after venous and arterial anastomosis. Results: The venous partial pressure of oxygen showed little increase after the venous anastomosis (mean, 115.7 percent; p = 0.0022). In contrast, venous partial pressure of oxygen increased markedly after the arterial and venous anastomosis in most of the patients (mean, 177.8 percent; p < 0.0001). Similarly, venous partial pressure of carbon dioxide, after both anastomoses, decreased to a lower level than before the additional anastomosis in most patients (mean, 93.1 percent; p = 0.035). Conclusion: The authors conclude that the additional anastomosis of both the artery and the vein is recommended if it is possible.

Development of an experimental model of infected skin ulcer.

A model of infected skin ulceration could prove useful in assessing the clinical effectiveness of antimicrobial ointments and dressings. However, no such models have been previously established. Three types of wound were induced in rats: full‐thickness wounds covered with gauze, burn wounds and wounds resulting from mechanical trauma. Wounds were inoculated with S. aureus or P. aeruginosa. Persistent infected wounds were observed only in full‐thickness wounds covered with gauze. In a second experiment, colonies of P. aeruginosa or S. aureus were counted within 15 × 15 mm full‐thickness wounds covered with gauze. Wounds were inoculated with 1·0 × 106 colony‐forming units (CFU) of P. aeruginosa or S. aureus and then sealed to ensure an enclosed environment. Tissue bacterial counts exceeded 106 CFU/g from the next day until day 9 after infection. Bacterial counts exceeded 108 CFU/ml in wound exudate collected between days 1 and 7. We have developed a model of wound infection in which persistence of infection can be achieved for 9 days following ulceration due to the application of gauze to the base of a full‐thickness wound.

Construction of pigmented skin equivalent and its application to the study of congenital disorders of pigmentation

We have constructed a pigmented skin equivalent and used it to study the hyperpigmentation seen in café-au-lait macules to elucidate whether the pigmented skin equivalent could be used as a model of congenital hyperpigmentary disorders. When we used fibroblasts derived from café-au-lait macules of neurofibromatosis type 1, the amount of pigment was significantly greater than in models using cells derived from normal skin. Quantities of pigment were not seen when keratinocytes derived from solitary café-au-lait macules were used, a possible reason being that keratinocytes on the skin equivalent are in a proliferating condition and are not well-differentiated enough to act on other cells. Our results suggested that our pigmented skin equivalent is useful for the study of congenital hyperpigmentary disorders, although insufficient differentiation of keratinocytes might be a disadvantage.

Epidermal hyperpigmentation in non-syndromic solitary cafe-au-lait macules may be associated with increased secretion of endothelin-1 by lesional keratinocytes.

To clarify the mechanism of accentuated melanisation in non-syndromic solitary cafe-au-lait macules we used an enzyme-linked immunosorbent assay (ELISA) to measure the concentration of melanogenic cytokines secreted by cultured keratinocytes and fibroblasts derived from the skins of the macules and compared them with those derived from normal people. Endothelin-1 (ET-1) was significantly increased in cultured keratinocytes in the macules compared with the normals. In contrast, the secretion of other cytokines secreted by keratinocytes or fibroblasts did not differ between the groups. It may be that the increased secretion of ET-1 by epidermal keratinocytes has a role in the accentuated epidermal melanisation seen in non-syndromic macules.

A Temporoparietal Fascia Pocket Method in Elevation of Reconstructed Auricle for Microtia.

Background: In two-stage procedures for reconstruction of microtia, an axial flap of temporoparietal fascia is widely used to cover the costal cartilage blocks placed behind the framework. Although a temporoparietal fascia flap is undoubtedly reliable, use of the flap is associated with some morbidity and comes at the expense of the option for salvage surgery. Methods: The authors devised a simplified procedure for covering the cartilage blocks by creating a pocket in the postauricular temporoparietal fascia. In this procedure, the constructed auricle is elevated from the head superficially to the temporoparietal fascia, and a pocket is created under the temporoparietal fascia and the capsule of the auricle framework. Then, cartilage blocks are inserted into the pocket and fixed. A total of 38 reconstructed ears in 38 patients with microtia ranging in age from 9 to 19 years were elevated using the authors’ method from 2002 to 2014 and followed for at least 5 months. To evaluate the long-term stability of the method, two-way analysis of variance (p < 0.05) was carried out to analyze the effect on the projection angles of the method (an axial temporoparietal fascia flap method versus a temporoparietal fascia pocket method) over long-term follow-up. Results: Good projection of the auricles and creation of well-defined temporoauricular sulci were achieved. Furthermore, the sulci had a tendency to hold their steep profile over a long period. Conclusions: The temporoparietal fascia pocket method is simple but produces superior results. Moreover, pocket creation is less invasive and has the benefit of sparing temporoparietal fascia flap elevation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Successful Treatment With Lymphovenous Anastomosis for Lower ExtremityEdema Secondary to Lipiodol Lymphangiography

Background: Chylothorax is one of the complications after thoracic surgery and treated by conservative or surgical means. Lipiodol lymphangiography is one of the options and it causes obliteration of chylous leak by inflammatory manner. In this article, we describe a case of lymphedema of the bilateral lower extremities occurs after lipiodol lymphangiography and it is treated successfully by lymphovenous anastomosis. Case presentation: A 67-year-old man presented with refractory chylothorax after subtotal esophagectomy and thoracic lymph node dissection. His chylothorax developed 4-month later of subtotal esophagectomy and was refractory to the conservative treatment (i.e. tube thoracostomy). He was referred to our department to treat chylothorax. We chose lipiodol lymphangiography as the treatment. Lymphatic duct of left foot was detected with indocyanine green and exposed to inject lipiodol into lymphatic duct directly. Chylothorax improved immediately after lipiodol lymphangiography and his edema of right lower extremity emerged 22-month later of lipiodol lymphangiography. We considered that his lower extremity edema was caused by lipiodol lymphangiography and performed lymphovenous anastomosis. Lymphovenous anastomosis was performed at the proximal of right thigh and the dorsum of the foot. At six-month later of lymphovenous anastomosis, we revealed that his right lower extremity had become thinner significantly, nevertheless laterality remained. Conclusion: To our best knowledge, this is the first report of lymphedema of the bilateral lower extremities after lipiodol lymphangiography for chylothorax. Lymphovenous anastomosis is a treatment option for such condition.