Squamous cell carcinoma of the lip. A retrospective study of 146 patients.

BACKGROUND: Squamous cell carcinoma of the lip (SCCL) accounts for 90% of all tumours of the oral cavity. We present a series of 146 patients with SCCL studied in our hospital. OBJECTIVE: To evaluate and identify the primary tumour parameters related to local and lymph node recurrence. METHODS: We retrospectively analysed the clinical characteristics, surgical procedures and tumour recurrences of the 146 patients diagnosed with SCCL in Hospital Universitario Fundación Alcorcón (Spain). RESULTS: A total of 122 of the 146 patients (91.7%) showed tumour stage ≤ T1N0M0 at diagnosis, and 11 (8.3%) showed stage >T1N0M0. Local recurrences were observed in 11 of the 146 patients (7.5%), and five patients (3.4%) developed lymph node metastases during follow-up. Kaplan-Meier survival analysis showed an increased tumour size to imply a greater risk of local recurrence (P = 0.025). The probability of local recurrence over the 24 months of follow-up was 1% for tumour stages ≤ T1N0M0 and 20% for stages ≥ T1N0M0. There appears to be a greater tendency towards local relapse in male patients, in smokers, patients living in rural areas, in lower lip tumours and in those patients showing infiltration at physical exploration. Eleven patients (8%) died during follow-up, although in only two of them (18%), SCCL was the cause of death. CONCLUSION: The low tumour stage of our patients may explain the few local and lymph node disease recurrences seen in our study. We have shown tumour size to be directly related to the probability of local recurrence.

Organelle distribution in chick neuroepithelial cells: effects of colchicine and cytochalasin B.

The intracellular distribution of mitochondria, cytoplasmic inclusions and rough endoplasmic reticulum cisternae of chick neuroepithelial cells was investigated at neurulation stages 6, 8, 10 and 12. These neuroepithelial cells were subdivided into three zones: apical, median and basal and the distribution percentages of distribution of these organelles were obtained. Mitochondrial distribution was related to the energy supply that mitochondria provide for apical microfilament contraction. Cytoplasmic inclusions were distributed preferentially in the apical zone of the neuroepithelial cells during the four stages. Rough endoplasmic reticulum cisternae were homogeneously distributed in the three zones at stages 10 and 12, but at stages 6 and 8 there are more elevated percentages of rough endoplasmic reticulum in the apical zones than in the other zones. Experimental treatments with colchicine and cytochalasin B does not modify the patterns of mitochondria and rough endoplasmic reticulum cisternae but alters the distribution of cytoplasmic inclusions. Finally, there is a correlation in the normal neurulating neuroepithelial cells between the distributions of mitochondria and rough endoplasmic reticulum distribution and between the distributions of mitochondria and cytoplasmic inclusions distribution. This relationship is retained in the treated neuroepithelial cells.

Differential Behavior Between Isolated and Aggregated Rabbit Auricular Chondrocytes on Plastic Surfaces.

A knowledge of the behavior of chondrocytes in culture is relevant for tissue engineering. Chondrocytes dedifferentiate to a fibroblast-like phenotype on plastic surfaces. Dedifferentiation is reversible if these cells are then cultured in suspension. In this report a description is given of how when chondrocyte aggregates formed in suspension are next seeded on plastic, most of them attach as round or polygonal cells. This morphological differentiation, with synthesis of type II collagen, is stable for long culture periods. This simple method can be of use as a model for studies of chondrocyte behavior on plastic. The results indicate that in addition to culture conditions, such as cell isolation method or cell density, chondrocyte behavior on plastic depends on the presence of aggregates.

Effects of extracellular matrix on the morphology and behaviour of rabbit auricular chondrocytes in culture.

Isolated chondrocytes dedifferentiate to a fibroblast-like shape on plastic substrata and proliferate extensively, but rarely form nodules. However, when dissociation is not complete and some cartilage remnants are included in the culture, proliferation decreases and cells grow in a reticular pattern with numerous nodules, which occasionally form small cartilage-like fragments. In an attempt to reproduce this stable chondrogenic state, we added a cartilage protein extract, a sugar extract, and hyaluronan to the medium of previously dedifferentiated chondrocytes. When protein extract was added, many cartilaginous nodules appeared. Hyaluronan produced changes in cell phenotype and behaviour, but not nodule formation. Protein extract has positive effects on the differentiation of previously proliferated chondrocytes and permits nodule formation and the extensive production of type-II collagen. A comparison with incompletely dissociated chondrocyte cultures suggests that the presence of some living cells anchored to their natural extracellular matrix provides some important additional factors for the phenotypical stability of chondrocytes on plastic surfaces. In order to elucidate if it is possible that the incidence of apoptosis is related to the results, we also characterized the molecular traits of apoptosis.

Intracellular distribution of yolk droplets, lipid bodies and Golgi apparatus in the chick neuroepithelial cells during neurulation.

Vitelline and lipidic inclusions which are present in the neuroepithelial cells during chick embryo neurulation show a typical intracellular localization in the apical zone of the cell. In the same cellular zone the Golgi apparatus can be seen during the successive stages of neurulation. These patterns of inclusion and organelle polarity during chick embryo neurulation may be related to active consumption of the reserves contained in inclusions during this morphogenetic process. Such an active consumption would imply a close relationship between the vitelline and lipidic inclusions and the Golgi apparatus. On the other hand, the apical position of the Golgi apparatus in the neuroepithelial cells reveals the remarkable apicobasal polarity of these cells which remains unchanged during chick embryo neurulation.

Delamination of neuroepithelium and nonneural ectoderm and its relation to the convergence step in chick neurulation.

We have analysed the characteristics of the neuroectoderm-nonneural ectoderm meeting point at several axial levels in relation to the mechanics of neurulation in each level. The results show wide differences at cephalic and somitic levels. At cephalic levels, where convergence plays an important role, the delamination process appears at the beginning of the convergence step. This phenomenon produces a major isolation of the basal lamina, forming a space between this structure and the epithelial sheet in whose basal surface a new basal lamina begins to form. This cavity contains abundant extracellular matrix stained with ruthenium red (RR) and tannic acid (TA), and its increase in volume correlates with the progressive convergence of neural folds. At somitic levels, where the convergence is not important, delamination involves the progressive formation of a half-moon-shaped cavity. This structure appears between a dorsal attachment point, in the tip of neuroectodermal wall, and a ventral attachment point which coincides with the point of bending that determines the bilateral furrow, if it exists. In this small cavity, delamination is not related to an isolation of basal lamina. The RR-staining of the extracellular matrix in this cavity is scarce and the volume increase is smaller than in the cephalic region. These results are discussed in terms of neural fold convergence and neural tube closure.