[Ultrastructural morphometric study of sex dimorphism in cells of the ductus granulosus of the submandibular glands of mice]. / Estudo morfométrico ultra-estrutural do dimorfismo sexual em células de ductos granulosos de glândulas submandibulares de camundongos.

The sexual dimorphism in the secretory cell of the granular convolated tubule of mouse submandibular gland was morphometrically studied in light and electronic microscope level. In semithin sections (0.5 micron) the nuclear volume (Bach, 1963) and the fractions of cellular volume occupied by the nucleus and by cytoplasm were determined (Chalkley, 1943). In twenty electronmicrographs per animal with a final magnification of x 15.000, using the Weibel's et al. (1966) multiproposition test system, were obtained relatives morphometrics data, which multiplied by the cytoplasmatic volume provided us the respective absolute values. The results showed a presence of a sexual dimorphism at subcellular level. The secretory cell of the male is higher and exhibit a greater volume when compared with that cells of the female. In the male that cells are characterized by a higher total volume of the endoplasmic reticulum, Golgi complex and secretory granules. The secretory granules and the condensation vacuoles size are more developed in male cells. The female secretory granular cells exhibit a greater absolute number of the condensation vacuoles and secretory granules, as well as, a higher mitochondria total volume and surface.

Ultrastructure of the exocrine pancreas in the snake Waglerophis merremii (Wagler).

Three types of serozymogenic cells were found in the secretory compartment of the snake exocrine pancreas. Type I cell was the most common and presented a well-developed granular endoplasmic reticulum arranged in cisternal and vesicular forms. The cisternal form was located predominantly in the basal regions of the cell and the vesicular form was found in the supranuclear regions of the cell next to a prominent Golgi complex. Mature secretory granules were seen at the cell apex. The cytoplasmic matrix of the Type II cells was electron dense but had only poorly-developed organelles. Secretory granules were rare. The cytoplasmic matrix of the Type III cells was electron lucent and the granular endoplasmic reticulum in the cisternal form was located predominantly in the supranuclear region, whereas the vesicular form was randomly distributed throughout the cytoplasm. The nucleus appeared pale due to the fine dispersion of the chromatin; the nucleolus was prominent. Centroacinar and intermediate cells were also examined.

Ultrastructure of the secretory compartment of the Rana catesbeiana exocrine pancreas.

In the Rana catesbeiana exocrine pancreas 2 types of serozimogenic cells could be observed. They were called light and dark cells. The light cells were observed in a greater number and presented the GER cisterns predominantly located in the basal region of the cell and the vesicular forms of the GER mainly in the supranuclear region. The Golgi complex was well developed and the secretory granules were grouped in the cell apex. The mitochondrion were distributed by the cytoplasm and the nucleous appeared in the basal region of the cell and presented a pale and vesiculous profile that made the nucleolus evident. The dark cells were observed in smaller quantity and in this cell occurred a predominance of GER vesicles. The cytoplasmic matrix presented an electron-dense appearance and a large quantity of free ribosomes. The Golgi complex is poorly developed, the secretory granules and the mitochondria are scarce. We could observe besides the light and dark cells, the centroacinar and the intermediate cells. The centroacinar cells lay in the luminal border of the acinar cells. They presented an electron-lucent cytoplasmic matrix where could be noted a few GER profiles and the secretory granules were absent. The intermediate cells showed, intermingled within the same cell, the zimogenic and the endocrine-like alfa and beta Langerhans granules.

Histological study on the prenatal development of the cheek-teeth of rabbits (Oryctolagus cuniculus).

The prenatal development of cheek-teeth of rabbits was studied by histological methods. Females from 15 to 30 days of gestation were sacrificed and their fetuses were collected and decapitated. The heads were fixed in buffered neutral formalin and paraffin embedded. Sagittal and frontal sections of 7 mu were obtained and stained with hematoxylin-eosin. The first tooth-germs observed were the m3 and m3, in the animal of 16 days of fetal life. One day after the m4 and m4 are observed in the bud stage. The last teeth to initiate development in the fetal rabbits are the M3 and M3 at 30 days. Only the m3, m4, m3 and m4 start cementogenesis in the prenatal stage.

Histological study on the postnatal development and sequence of eruption of the mandibular cheek-teeth of rabbits (Oryctolagus cuniculus).

The postnatal development and sequence of eruption of mandibular cheek teeth of rabbits were studied by histological methods. Hemi-mandibles were dissected and sectioned in longitudinal sections of 7 mu and stained with hematoxylin-eosin and Masson's trichrome. The presence of two mandibular deciduous molars which are replaced by corresponding premolars and of three mandibular permanent monofisary molars was confirmed. Eruption of deciduous molars of the mandible begins at 4 days after birth and of the mandibular permanent molars at 9 days, while that of mandibular premolars occurs at 23 days, replacing the mandibular deciduous molars which have exfoliated. At 32 days all the mandibular permanent cheek-teeth are erupted. At birth the mandibular deciduous molars are completely developed and at 4 days their root resorption is initiated. At the first day P3 is in the bell stage and the P4 has begun dentinogenesis. In M1 and M2 amelogenesis is observed.