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Biomedical subjects

R A Lopes

Publications and source records attributed to R A Lopes.

At least 37 records · Page 2Linked to original sources

The male reproductive organs in the chronic phase of experimental Chagas' disease.

A previous study showed amastigote forms of Trypanosoma cruzi in the sex organs of male mice 15 days after inoculation. The purpose of the present work was to investigate the sequelae occurring in the male reproductive system during a later phase of Chagas' disease. Depleted germinal epithelium and release of immature germ cells into the tubular lumen were observed in the testis of chronic chagasic mice. The relative weights of the epididymis, vas deferens and seminal vesicle were significantly increased. Histological examination revealed a sharp thinning of the ductal and acinar walls. The results are discussed in terms of a neuromotor disturbance leading to sperm retention.

Animals↗

The male reproductive organs in experimental Chagas' disease. I. Morphometric study of the vas deferens in the acute phase of the disease.

Amastigote forms of Trypanosoma cruzi (Bolivia strain) were detected in the sex organs of male mice 15 days after inoculation. The presence of the parasite close to the lumen of the seminiferous tubules and mixed with spermatozoa in the lumen of the epididymal duct suggests the possibility of transmission of Chagas' disease through coitus. Morphological analysis of the vas deferens revealed structural alterations compatible with the early form of chagasic esophagopathy.

Acute Disease↗

Histopathological study of von Ebner's lingual salivary glands in Trypanosoma cruzi-infected mice.

In the present study we describe the histopathological alterations induced by RC strain of Trypanosoma cruzi in the mouse von Ebner's lingual salivary glands during the acute period of infection: Amastigotes were found in von Ebner's gland acini cells, excretory duct cells, intralobular connective tissue, inside the acini lumen and muscle fibres. Desorganized parenchyma with impairment at the acinar and duct level, and intense lymphoplasmocytic infiltrate were seen.

Animals↗

Morphological, morphometric and stereological study of submandibular glands in rats with lesion of the anteroventral region of the third ventricle (AV3V).

Lesions of the antero-ventral region of the third ventricle induce in the rat submandibular gland parenchyma, atrophy through vascular ischemia, and simultaneously increased fibrosis of the connective tissue, probably by alteration of the pituitary gonadotropins (FSH, LH), thyrotrophic hormone (TSH), growth hormone and probably insulin levels.

Animals↗

A new aspect of the morphological transformation of Trypanosoma cruzi brought about by environmental variation.

The development of Trypanosoma cruzi has been described both in vertebrate and invertebrate hosts, and the morphological transformations of the parasite have been studied in both cell-free cultures and tissue cultures. The investigators who studied this topic have emphasized the fact that the morphogenesis of T. cruzi may be associated with a series of factors. In the present study, we noted that when bloodstream trypomastigotes leave a vertebrate host reaching the digestive tract of triatomines through the blood sucking action of these vectors, specific culture by blood plating or maintenance of blood in physiological saline at different temperatures shows a phenomenon of trypanosome joining, with intensive movement of internal organelles (nucleus and kinetoplast) and junction at the kinetoplast level. Different situations may occur after this phenomenon, such as flagellate separation, passage of kinetoplast content from one individual to another, transformation into rounded elements that approach the pairs of agglomerate, or the formation of spherical elements similar to cyst-like bodies. When observed by light or phase-contrast microscopy, these bodies appear to be static and show inner structures moving in circles or in disorderly manner. On the basis of the molecular studies carried out by other authors, who observed that not all proteins synthetized from DNA are of immediate usefulness in the cell, but need to undergo activation by the action of another protein or of environmental variation, we may infer that T. cruzi, under adverse conditions, i.e. a change in habitat, may undergo transformations, taking on different forms for the exchange of genetic information for adaptation to the environment and for possible continuity of the evolutionary cycle.

Animals↗

On the fine structure of the parotid gland of tufted capuchin monkey, Cebus apella.

The parotid gland of the tufted capuchin monkey (Cebus apella) was examined by scanning and transmission electron microscopy. In general the ultrastructural morphology of this gland appears similar to that described in spider and squirrel monkeys. This study has established that the gland is serous. Acinar cells, which contain a well developed granular endoplasmic reticulum and a prominent GOLGI complex, produce a single secretory material. Myoepithelial cells are present around acini and around intercalated ducts. The intercalated ducts, which are composed of cells that show no evidence of secretory activity, lead into striated ducts.

Animals↗

Can cocaine block the uptake of neurotoxin produced by Trypanosoma cruzi?

In the present study we describe the morphological and morphometric alterations induced by Trypanosoma cruzi (Bolivia strain) on the mice parotid gland, and the action of cocaine on the development of the gland of growing infected animals. The acinar cells of animals inoculated 28 d after birth showed reduced eosinophilia, greater chromatin condensation, reduced height, and basally dislocated nucleus. The area occupied by the acini was decreased and the nuclear volume was reduced. Reduced height of epithelial cells and decreased nuclear volume occurred in the striated and excretory ducts. The presence of lymphoplasmocyte infiltrates was also observed. The present results indicate delayed development of the infected mouse parotid gland. Our results indicate that cocaine perceptibly reduced the atrophy of the acinar cells and minimized the histopathological changes caused by T. cruzi in the parotid gland, in addition to significantly increasing the survival of infected animals. The presence of stroma with dilated capillaries and frequent inflammatory infiltrates showed that cocaine does not interfere with the inflammatory response.

Animals↗

Light and scanning electron microscopic studies of the effects of CO2 laser on the palatine mucosa of rats.

In order to verify the effects of CO2 laser on the palatine mucosa of rats, 15 animals were utilized. The animals were anaesthetized with thionembutal by intra-peritoneal injection and the palatine mucosa of each animal was irradiated with a single pulse of 10 W. The results showed that immediately after the irradiation of CO2 laser, the formation of small cavities is observed. The wound healing post operationem is gradually in 1 week. The region is totally occupied by neoformed connective tissue and epithelial cells. Numerous polymorphonuclear cells and fibroblasts may be seen between the neoformed collagen fibres.

Animals↗

Influence of age on the production of rat spermatozoa, on their concentration in the cauda epididymidis, and on FSH, LH and testosterone plasma levels.

Testis samples were taken from young (3 months), middle-aged (12 months) and aged (24 months) male rats, processed, stained and examined via a light microscope. There were no prominent abnormal germinal epithelium and interstitial tissue. However, the aging process promoted a significant decrease in the mean amount of spermatids 19 per cross tubular section, and in the amount of Sertoli cells per cross tubular section in 24-month-old rats. The concentration of spermatozoa in the cauda epididymidis showed a gradual decrease from 3 to 12 and 24 months. After hCG injection all groups of animals exhibited an increase in plasma testosterone level, although the response was smaller in 12- and 24-month animals compared to the young mature (3 months) ones.

Aging↗

Functional disturbance of rat sexual accessory glands in an early phase of lead intoxication.

In order to investigate the effects of chronic lead intoxication on sexual accessory glands adult male Wistar rats were poisoned by ad libitum ingestion of lead acetate at concentrations of 0.5 g/l and 1.0 g/l for 90 d. Blood lead exhibited a significant increase in both treated groups. A decrease in hematocrit and hemoglobin, besides a rise in glycemic levels, confirmed lead intoxication. No sign of lesion was detected upon histologic examination of prostate, seminal vesicle, and coagulating gland. A morphometric technique revealed that, in this early phase of intoxication, no alteration occurred in the prostate's and seminal vesicle's epithelial height. However, a significant decrease in fructose content was observed in both lead treated groups. The results, revealing a precocious envolvement of male sexual accessory glands in lead intoxication, were related to disturbance in plasma testosterone level and also probably in androgen receptors.

Animals↗

Morphometric and stereological analysis of rat testis and epididymis in an early phase of saturnism.

Adult male Wistar rats were poisoned by ad libitum ingestion of lead acetate at concentrations of 0.5 g/l and 1.0 g/l in drinking water, for 90 days. Blood lead exhibited a significant increase in both treated groups. A decrease in haematocrit and haemoglobin, together with a rise in glucose levels, confirmed lead intoxication. No signs of lesion were detected upon histological examination of testes, caput and cauda epididymidis. In this early phase of intoxication, no alteration occurred in the seminiferous tubule diameter, in the germinal epithelium height, nor in the rate of spermatogenesis and the production of spermatozoa. The caput epididymidis also showed no structural change. In the cauda epididymidis, however, an increase in ductal diameter, and a decrease in epithelial height, were observed. The concentration of spermatozoa stored in the caudal region of the epididymis exhibited a significant increase in lead-treated animals. The results, which reveal an early involvement of cauda epididymidis in lead intoxication, are discussed in terms of a disturbance in the neuroendocrine mechanism controlling the multiple epididymal functions.

Animals↗