ULTRASTRUCTURE OF THE GERMINATIVE EPITHELIUM IN A GOAT WITH A 5/15-ROBERTSONIAN TRANSLOCATION

The spermatogenesis of two goats bearing a 5/15 Robertsonian translocation was investigated by electron microscopy. There was no dramatic change in the morphology of the cells of the spermatic line. All cells of the seminiferous epithelium seemed quite normal at the ultrastructural level. However a certain disturbance in the cell localization and some morphological abnormalities involving nuclear structure were seen. Spermatocytes and spermatids normal in appearance were observed, but a great number of cells presented two or more nuclei. These cells were frequently seen to become degenerated during spermatogenesis. We believe that unbalanced spermatocytes degenerate during the process and only some spermatocytes succeed in fertilizing gametes.

ULTRASTRUCTURE OF THE HINNY (EQUUS-ASINUS X EQUUS-CABALLUS) SEMINIFEROUS EPITHELIUM

The gonads and the germinative cells of 3 male hinnies were studied with light and transmission electron microscopy with the aim to observe the development of germ cells and verify the morphological modifications due to the hybridization. The hinny seminiferous epithelium presented Sertoli cells and spermatogonia with normal features and anomalous spermatocytes I. The other cells from the spermatogenic sequence were not seen. Most of the alterations began to occur in the cytes I, which presented nuclear vacuolization and deposits of amorphous material between the carioteca and the nuclear lamina, forming vesicles, or exaggerated chromatin condensation, resulting in pyknosis. In the cytoplasm vacuolization was also observed, besides organelle destruction.The arrest of meiosis due to lock of chromosome homologies leads to germinative cell degeneration and, therefore, the spermatogenesis arrest. This fact causes a profound alteration in the seminiferous epithelium morphology in comparison with the parental species.

Morphologic changes in the vesical transition epithelium of alcoholic rats

Few studies are available about the effect of alcohol on the epithelium of the urinary bladder. In the present investigation we studied the ultrastructure of the vesical transition epithelium of normal rats and of rats submitted to experimental chronic alcoholism. Adult rats were submitted to experimental chronic alcoholism by the ingestion of sugar cane liquor. The vesical epithelium was examined after 60, 120, 180 and 240 days of alcohol treatment by transmission electron microscopy. Surface cells presented nuclear and cytoplasmic changes and marked cellular desquamation. There was an increase in multivesicular bodies and lysosomes suggesting cell degeneration. Mast cell infiltration was observed, possibly related to increased epithelial sensitivity. Intercellular spaces were frequently observed. The transition epithelium of the urinary bladder was found to be sensitive to the action of alcohol, as demonstrated by the changes in the components of the blood-urine barrier, the greater sensitivity to inflammation, the increase in cell desquamation and the greater recycling of the apical membrane and of the fusiform vesicles of surface cells observed in alcoholic rats.

ULTRASTRUCTURE OF THE ILEUM EPITHELIUM OF MELIPONA QUADRIFASCIATA ANTHIDIOIDES (HYMENOPTERA, APIDAE, MELIPONINAE)

Study of the epithelial morphology of a stingless bee ileum from the pyloric valve to the last portion of high absorptive cells shows that although the bee ileum is an anatomically undifferentiated tube, four types of epithelial cells along the tube (in addition to the valve cells) indicate physiological differentiation. The anterior end seems to be less active in reabsorption, while the posterior region contains cells with typical morphology of an ion pump and permits conclusions about the mechanisms of absorption in the posterior end of the intestine. (C) 1994 Wiley-Liss, Inc.

Heterotopic gastrointestinal cyst partially lined with dermoid cyst epithelium

We report a rare heterotopic gastrointestinal cyst located in the right submandibular/submental area with histopathologic features that included portions resembling a dermoid cyst. Some theories of pathogenesis are discussed, and an origin of this lesion in entrapped undifferentiated endodermal cells is suggested.

Antioxidant activity of the melanin pigment extracted from Aspergillus nidulans

Melanins are pigments of high molecular weight formed by oxidative polymerization of phenolic or indolic compounds. A number of fungi, including Aspergillus nidulans, produce pigments related or identical to melanin, which are located on cell walls or exist as extracellular polymers. The aim of the present study was to assess the antioxidant activity of synthetic melanin and of the pigment extracted from the mycelium and culture medium after growth of the highly melanized strain (MEL1) from A. nidulans. The ability of the melanin pigment to scavenge the oxidants HOCl and H2O2 was evaluated by inhibition of the oxidation of 5-thio-2-nitrobenzoic acid (TNB) using several melanin concentrations. The results showed that the pigment of the MEL1 strain competes with TNB for H2O2 and HOCl, inhibiting TNB oxidation in a concentration-dependent manner. For the HOCl oxidant, this inhibition was comparable to that of synthetic melanin, whose IC50 values were quite close for both pigments. Thus, our results suggest that the melanin from A. nidulans is a potential HOCl scavenger and may be considered a promising material for the cosmetic industry for the formulation of creams that protect the skin against possible oxidative damage.

COMPARATIVE STUDIES ON PIGMENT GRANULES AND PIGMENT DISTRIBUTION IN THE COMPOUND EYES OF WILD-TYPE AND MUTANT WORKER HONEYBEES .2. AN ULTRASTRUCTURAL ANALYSIS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Activity of the Ovarian Germinal Epithelium in the Freshwater Catfish, Pimelodus maculatus (Teleostei: Ostariophysi: Siluriformes): Germline Cysts, Follicle Formation and Oocyte Development

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Intraoperative bleeding during vitrectomy for diabetic tractional retinal detachment with versus without preoperative intravitreal bevacizumab (IBeTra study)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)