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F M Cardoso

Publications and source records attributed to F M Cardoso.

11 recordsLinked to original sources
PubMed2002

Plasma and testicular testosterone levels, volume density and number of Leydig cells and spermatogenic efficiency of rabbits.

Plasma and tissue testosterone concentrations were determined by radioimmunoassay in 12 eight-month-old sexually mature New Zealand White rabbits and evaluated for possible associations with spermatogenic efficiency as well as with volume density and number of Leydig cells. Testicular tissue was processed histologically and histometry was performed in order to quantify germ cells, Sertoli cells and Leydig cells. Spermatogenic efficiency, reported as the ratios among germ cells (spermatogonia, primary spermatocytes and round spermatids) and by the ratio of germ cells to Sertoli cells, was not associated with testosterone levels. However, Leydig cell parameters such as number of Leydig cells per gram of testis, total number of Leydig cells per testis and percent cell volume of Leydig cell nuclei were correlated significantly with testosterone levels. The statistically significant correlation (r = 0.82, P<0.05) observed between testosterone levels and the number of Leydig cells per gram of testis suggests that, in the rabbit, the latter parameter can serve as a criterion for monitoring testosterone levels in this species under normal conditions.

Animals↗
PubMed1998

Duration of spermatogenesis and sperm transit time through the epididymis in the Piau boar.

The Piau boar is a rustic breed of economical importance in Brazil. The duration of spermatogenesis and sperm transit through the epididymis in Piau boars was estimated using intratesticular injections of tritiated thymidine. Animals were sacrificed 1 h, 7 days, 14 days, 21 days, 34 days, and 36 days after injections. Each cycle of spermatogenesis in Piau boars lasts 9 +/- 0.2 days. At least 9 days are necessary for spermatozoa to traverse the entire epididymis. Considering that the total duration of spermatogenesis takes about 4.5 seminiferous epithelium cycles, spermatogenesis was estimated to take 40.6 days. The primary spermatocytes life span is 13.5 days, while spermiogenesis in Piau boars lasts 14.5 days. Staging in Piau boars was based on tubular morphology system. The relative stage frequencies in these boars, based on approximately 1200 seminiferous tubule cross-sections for each animal, were as follows: stage 1, 11.7 +/- 0.7%; stage 2, 14.3 +/- 0.3%; stage 3, 5.4 +/- 0.1%; stage 4, 12.1 +/- 0.6%; stage 5, 9.6 +/- 0.4%; stage 6, 17.2 +/- 0.4%; stage 7, 15.4 +/- 0.8%; and stage 8, 14.3 +/- 0.9%. The duration of spermatogenic events and the relative stage frequencies in Piau boars differ slightly from those observed in improved swine breeds.

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PubMed1979

Age-related changes in the seminal vesicles of a Brazilian (Nelore) zebu.

Age changes in the structure of the seminal vesicles and in the rate of production of fructose and citric acid have been studied in a Brazilian (Nelore) zebu, from the fetal period to 36 months of age. At 3 and 6 months, the microscopic anatomy of the gland resembled that of the fetus; the tubules of the seminal vesicles had a reduced diameter and a low epithelial layer; only a few presented traces of secretion, and tissue contents of fructose and citric acid were accordingly low. At 12 months, the tubules were more ramified and had a larger diameter. In the 18-month-old animals the seminal vesicles presented substantial modifications; the tubules were large, with irregular lumina and surrounded by narrow stroma, the epithelial layer was higher than that of previous stages and its columnar cells had nuclei located basally. Tissue levels of fructose increased rapidly between 12 and 18 months. At 24 months, the seminal vesicles had reached the adult condition characterized by intense proliferation of tubules with irregular lumina and abundant secretory material. Numerous dark columnar cells were found in the epithelium. Seminal vesicles of Nelore zebus contain less fructose and citric acid than those of taurine bulls of comparable age.

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PubMed1977

Blood supply to the testis of a Brazilian marsupial (Didelphis azarae) and its abdominotesticular temperature gradient.

The testicular arteries of Didelphis azarae originate from the abdominal aorta either independently from each other or by way of a common trunk. Accessory testicular arteries may be found. At the spermatic cord they form a rete mirabile having 26.8 +/- 5.0 and 29.3 +/- 4.9 slender branches on the right and left sides, respectively. The arterial branches are intermingled with veins of similar caliber and number. Near the testis the branches of the rete reunite in a single vessel which then penetrates the parenchyma of the testis. Inside the testis the artery divides usually into two main branches that course toward the caudal pole. The rectal, scrotal and testicular temperatures were 32, 28.5 and 30.4 degrees C, respectively, appearing than an abdominotesticular gradient temperature exists in this animal. Whether this mechanism is thermoregulatory for the normal spermatogenesis cannot be inferred from the present work.

Animals↗
PubMed1977

Microscopic anatomy of the scrotum, testis with its excurrent duct system and spermatic cord of Didelphis azarae.

The authors give a description of the microscopic anatomy of the scrotum, testis and its excurrent duct system and the structures of the spermatic cord. The scrotal skin of Didelphis azarae is hairy with the surface marked by shallow grooves and spotted with black pigmented areas. Clear cells and mitotic figures are frequently seen in the basal region. The sweat glands are tubular, apocrine, with alcian-blue- and PAS-positive secretion, presenting large myoepithelial cells. The tunica dartos is poorly developed. The tunica vaginalis is constituted by three layers, presenting patches of melanocytes in variable extensions. The tunica albuginea is composed preponderantly of collage and thin elastic fibers without muscle fibers. The interstitial tissue presents connective cells and a large number of Leydig cells. Mast cells were not observed. The tunica propria of the seminiferous tubuli is fibroelastic with two or three layers of elongated cells. The straight tubuli are divided into three different portions lined by epithelium with variable height. These tubuli at the mediastinum join each other to form a single duct near the cranial pole of the testis. The extratesticular segment of the efferent duct divides initially into two and then into three or four smaller flexuous ductuli to constitute the head of the epididymis. The spermatic cord shows a well-developed cremaster muscle. A collagenous fibrous band separates the muscle from the deferent duct and vessels. Mast cells are observed among the muscle fibers of the cremaster and the tunica adventitia of the blood vessels.

Animals↗
PubMedDate not supplied

Gonadal and extragonadal sperm reserves of the Brazilian Nelore zebu (Bos indicus).

Gonadal and extragonadal sperm reserves were estimated through hemocytometric method in six Nelore zebu bulls, aging 4-6 years, with normal spermatogenesis, and kept at sexual rest. Gonadal sperm reserve was estimated to be 47.8 +/- 5.8 X 10(6) sperm cells/g testis parenchyma and 9.8 +/- 1.7 X 10(9) sperm cells/testis. Using a time divisor of 4.94 days the daily sperm production was estimated to be 10.0 +/- 0.9 X 10(6) sperm cells/g testis parencyma/day and 2.0 +/- 0.3 X 10(9) sperm cells/testis/day. Epididymal sperm reserve amounted 11.9 +/- 1.6 X 10(9) spermatozoa/organ, distributed as follows: 35.3 +/- 3.6% in the head, 16.9 +/- 1.7% in the body and 47.7 +/- 3.7% in the tail.

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