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The quenching rate constants of the excited triplet state of Rose Bengal (RB) by oxygen (k(obs)) were measured in ethylene glycol (EG) at different temperatures using nanosecond laser flash photolysis. Although a plot of the quenching rate constant k(obs) for RB triplet state vs oxygen concentration is linear at 20 degrees C, the oxygen dependence of k(obs) does not exhibit linearity but upward curvature at high temperatures from 130 to 140 degrees C. The upward curvature at high temperatures is not well-described by a kinetic scheme first postulated by Gijzeman et al., which is characterized by exciplex formation and a unimolecular dissociation of the exciplex to products, but instead by a more comprehensive mechanism involving a bimolecular dissociation in addition to a unimolecular one. The measurements of the oxygen dependence of k(obs) for RB triplet state at different temperatures yielded a reaction enthalpy for the exciplex formation of 150 kJ mol(-1). Due to the large exothermic reaction enthalpy, equilibrium was obtained for the exciplex at 20 degrees C even at low oxygen concentration and the bimolecular quenching by oxygen became the major dissociation process. The equilibrium attainment and bimolecular dissociation provide a linear oxygen dependence of k(obs) to all outward appearances. Therefore, linearity does not always mean that exciplex dissociation proceeds solely through a unimolecular mechanism.

A 54-year-old male presented with the complaint of a painful sore on the left side of his tongue. Our examination found an ulcer 15 x 20 mm in size on the left edge of the tongue, with peripheral indurations. The lesion was diagnosed histopathologically as squamous cell carcinoma (T2N0M0). Consequently, the lesion was surgical removed and radical neck dissection was performed. Four months after the operation, two unusual cyst-like lesions were identified in the parapharyngeal space by CT and MRI. A biopsy specimen revealed recurrent carcinoma with a cyst-like structure. The route of the tumor metastasis into the parapharyngeal space was obscured, but it was speculated that the excessive lymph accumulation was due to a lymphatic occlusion caused by the surgical procedure, proliferation of the metastatic carcinoma, or stagnation and accumulation of tissue fluid caused by parapharyngeal invasion by the recurrent lesion.

In this study, a unique fiber system in the subectodermal mesenchyme of the chick limb bud was visualized immunohistochemically with the use of a novel monoclonal antibody termed "FB1." This antibody stained a subset of extracellular fibers in the embryonic mesenchyme. Among the fibers visualized, those running perpendicularly to the limb bud ectoderm became progressively prominent in their thickness and length, and organized into a parallel array in the subectodermal region. This fiber system was distinct from that of major collagens, fibronectin, or tenascin. A molecule immunoprecipitated with FB1 comigrated with JB3 antigen, or chicken fibrillin-2. The fibers visualized immunohistochemically by FB1 and JB3 were indistinguishable from each other, and ultrastructurally appeared to be bundles composed of tubular-like microfibrils that originated directly from the ectodermal basal lamina. They lacked the amorphous deposits that are characteristic of elastin. A similar array of subectodermal fibers was also found in the developing axilla and some truncal regions, again well before the development of a definitive dermis. These findings suggest that a parallel array of subectodermal FB1-positive fibers constitutes a precocious fiber system in the presumptive dermis prior to the substantial formation of collagenous fibers. These fibers could be developmentally linked to oxytalan fibers, which are known to be present in the papillary dermis in mature cutaneous tissue.

The embryonic epicardium is formed by the spreading of cells derived from the extracardiac proepicardial organ over the myocardial surface after transfer to the dorsal side of the myocardium via a bridge of villous projections. Using whole-heart immunostaining for keratin, we found that the chronology and pattern of epicardial formation in the chick was basically identical to that reported previously in the quail. However, discrete epicardial islands were observed on the ventrolateral surface of the atrioventricular canal as well as in two previously reported areas. Closer examination by scanning electron microscopy demonstrated the presence of isolated, sparsely distributed epicardial cell clusters on both the dorsal and ventral surfaces of the myocardium. These cells showed a surface morphology similar to that of the epicardial cells at the advancing edge of the spreading epicardial sheet and possessed numerous well-developed filopodia, suggesting active motility. These clusters are probably seeded onto the myocardium by vesicular transport from proepicardial villi, and our findings suggest that the resulting small, localised patches of epicardial cells might accelerate, supplement and tune the epicardial formation mediated by radial spreading of the epicardial sheet in the chick embryonic heart.

We experienced a family in whom sleep apnea syndrome (SAS) was recognized in six members and habitual snoring in seven members among 26 subjects of four generations. In all members with snoring, the disorder was noticed before the age of 20. Hypercapnic response study showed normal findings, and ultrafast magnetic resonance image of the upper airway revealed that the obstruction of the upper airway occurred at the velopharyngeal portion during apneic episodes in all SAS-afflicted subjects. In this family, the similar craniofacial structural abnormalities were thought to cause the aggregated occurrences of the disorders at young ages, and obesity was regarded as a contributor for the aggravated symptoms.

In the developing chick heart, endothelial cells in the atrioventricular canal (AV) undergo a series of morphological changes and transform into cushion mesenchymal cells. In the present scanning electron microscopic study, we examined the abluminal surface features of the AV endothelium through an artificial window in the myocardial wall. The AV endothelial cell at stages 12 or earlier had a smooth, flattened basal surface with only a few blebs. In the successive stages, the abluminal surface exhibited remarkable changes; 1) the number of blebs increased, 2) elongated microvillous projections emerged, and 3) a thick filopodium, or a migratory appendage developed. It appeared, however, that these changes do not occur synchronously within the entire AV endothelium but were initially observed mostly in the proximity of the endothelial "crease" which was a limited invagination of the endothelial sheet towards the underlying acellular matrix. In addition, even in the proximity of the crease, endothelial cells with flattened basal surfaces were also observed next to endothelial cells that showed apparent morphological indications of transition into mesenchymal cells. These findings suggest that AV endothelial cells are possibly heterogeneous in the competency of transformation into mesenchymal cells and such heterogeneity would be important for maintaining the continuity of the AV endothelium.

Background: Reconstruction of facial bone fractures complicated by frontal sinus destruction must seal off the cranial cavity from the upper respiratory tract to avoid ascending infections of the intracranial contents., Methods: We used a bipedicled galeopericranial flap for reconstruction of the extradural and subcutaneous spaces of the frontal region, which were infected with methicillin-resistant Staphylococcus aureus (MRSA) following unsuccessful coverage of the anterior cranial base with an anteriorly based pericranial flap., Results: The patient healed uneventfully without infection., Conclusion: Because a bipedicled galeopericranial flap has abundant blood supply, it can be used to cover a wide segment of the anterior cranial base. This is the first report of the application of a bipedicled galeopericranial flap for wide reconstruction of the anterior cranial base.

Several lines of recent evidence have suggested that transferrin plays a significant role in tissue interaction or morphogenesis at early stages of embryo development. In the present study, an anti-chicken transferrin antibody was produced and its basic characteristics were clarified as a basis for use in further studies. An antiserum termed Toraji 3 was raised against chicken transferrin and purified into IgG and ligand-affinity-purified fractions. These three preparations of the antibody gave an intense immunohistochemical signal in visceral yolk sac and developing liver, both of which are known to be major producers of transferrin in early development. In immunoblot analysis, these three preparations detected 70-kDa transferrin, whereas the ligand-affinity-purified preparation showed higher specificity. It was also demonstrated by enzyme-linked immunosorbent assay and immunoblotting that Toraji 3 antibody bound preferentially to chicken transferrin and showed a negligible binding to human transferrin.