[Contractile proteins and nonerythroid spectrin in the oogenesis of the clawed toad]. / Sokratimye belki i neéritroidnyi spektrin v oogeneze shportsevoi liagushki.

Distribution of contractile proteins, actin and myosin, and spectrin was studied in oogenesis of X. laevis. These proteins are present already at the previtellogenic stages, where they are diffusely distributed. During vitellogenesis actin and myosin are distributed in the animal region in a fibril-like way, while in the vegetal one they are concentrated around the yolk platelets. In the mature oocyte, distribution of actin and myosin again becomes diffuse. Spectrin forms in the vitellogenic oocyte a network all over the cytoplasm, while in the full-grown oocyte it is localized mostly in the subcortex of the animal region and disappears during oocyte maturation. All these proteins are present in the nuclei of oocytes. Changes in distribution of actin, myosin and spectrin during oocyte maturation are discussed with reference to the cortical contractility, spatial distribution of yolk platelets and regional sensitivity to cytochalasin B.

Development of horizontal tooth wear in maxillary anterior teeth from five to 18 years of age.

Sizes of horizontal wear facets of maxillary anterior teeth were studied longitudinally from the primary dentition at age five to the young adult dentition at the age of 18 years. By a planimetric method, we calculated the wear areas on dental casts taken at the ages of five, ten, 14, and 18 years from the dentition of 39 healthy, orthodontically untreated subjects with good morphological occlusion. For young adults, we also studied the association between the amount of wear and reported parafunctions, maximal bite force, salivary buffer capacity, salivary flow rate, and some cephalometric variables. Size of wear facets on all anterior teeth increased with age. Significant correlations were found between the total wear areas of the six anterior primary teeth at five years of age and those of their permanent successors at age 14 (r = 0.44) and 18 (r = 0.39). For an individual, tooth wear at five years of age was, however, of low predictive value for tooth wear in young adulthood, whereas tooth wear at 14 years of age predicted it well (r = 0.89). Highest correlations between tooth wear and background factors at 18 years of age were found for maximal anterior bite force (r = 0.44) and for the size of the gonial angle (r = -0.31). Wear of anterior teeth was not associated with reported parafunctions in young adulthood.

A radiological study of degenerative vascular changes in the external carotid region and carotid bifurcation.

In a series of 79 autopsies performed on subjects aged from 18 to 95 years occlusions in the external carotid, maxillary and inferior alveolar arteries were rare: only two cases were found in the maxillary and one in the inferior alveolar arteries. Tortuosity of the arteries increased with age, being most extensive in the external carotid and least in the inferior alveolar artery. Variations in the diameter of the maxillary artery occurred in 11 persons (14%), the incidence increasing with age. The youngest person showing such changes was aged 55 years. The average diameter of the arterial lumen of the inferior alveolar artery decreased with advancing age. This narrowing of the lumen also correlated with the loss of teeth. Calcified atherosclerotic plaques in the carotid bifurcation were present in 59% of the cases studied. In persons aged over 60 years a correlation was found between the carotid calcifications and coronary artery disease.