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Biomedical subjects

L Banek

Publications and source records attributed to L Banek.

11 recordsLinked to original sources
PubMed2001

Localisation of lanosterol 14alpha-demethylase in round and elongated spermatids of the mouse testis: an immunoelectron microscopic and stereological study.

Lanosterol 14alpha-demethylase (CYP51) is a microsomal cytochrome P450 enzyme involved in the postsqualene cholesterol biosynthetic pathway. CYP51 removes 14alpha-methyl group from lanosterol], forming FF-MAS (folicular fluid meiosis activating sterol) which accumulates in gonads. The goal of our study is to determine the expression of CYP51 protein in the male gonad. Using electron microscopic immunogold techniques, CYP51 is localised on inner and outer acrosomal membranes of male germ cells, the round and elongated spermatids. Significance of CYP51 localization on the acrosome which is a Golgi-derived organelle is not known, but we propose that CYP51-formed FF-MAS can function as a signalling sterol during fertilisation.

Acrosome↗
PubMed2001

The development of blood and lymph vessels of human parathyroid glands in embryonal, fetal and postnatal period.

The aim of the article is to investigate the development of blood and lymph systems in human parathyroid glands in prenatal and postnatal periods. The first capillaries are observed in these glands already in the lunar month 2. At the middle of pregnancy blood supply is increased, being extremely abundant in lunar months 9 and 10, as well as during the first year of life. As parts of the lymph system, intercellular lymph spaces are noticed in the parathyroid glands already in the lunar month 2, and also later, when lymph vessels are situated along the gland or in its connective capsule and within the gland parenchyma respectively. All these findings could be connected with the early function of these glands, as well as with the possibility that parathyroid hormone (PTH) is not transferred by blood only but by lymph as well.

Capillaries↗
PubMed1999

Mast cells in testicular biopsies of infertile men with 'mixed atrophy' of seminiferous tubules.

Mast cells in the bilateral testicular biopsies of 30 patients with a 'mixed atrophy' of seminiferous tubules were analysed. Seven biopsies from vasectomized patients served as controls. With regard to their characteristic location within testicular tissue, two groups of mast cells could be distinguished, in both control and infertile patients: 'interstitial' mast cells (located between Leydig and other interstitial cells as well as in the vicinity of blood vessels) and 'peritubular' mast cells (located in the close proximity of the tubular lamina propria or incorporated in the lamina propria itself). Morphometric data indicated a significant increase in the number and volume of mast cells in infertile patients when compared with controls. In the biopsies of infertile patients that were analysed both 'interstitial' and 'peritubular' mast cells showed a significant increase in their number and volume, although it appeared that 'peritubular' mast cells increased at a higher rate than 'interstitial' mast cells. A significant negative correlation was found between the following variables: volume and number of mast cells, testis volume and the status of spermatogenesis evaluated by Johnsen's scoring. It was concluded that the increased presence of mast cells is closely associated with an impairment of spermatogenesis.

Adult↗
PubMed1996

Effects of orchiectomy on the rat parotid gland--an ultrastructural and stereological study.

The relation of the tests/testosterone with the structure and function of the mammalian parotid gland has so far been poorly investigated. The present study deals with the morphology of the rat parotid gland and its changes after orchiectomy and testosterone substitution. The glands of control and experimental animals (orchiectomized and orchiectomized with testosterone substitution) were analyzed by electron microscopy and stereology. In orchiectomized animals 30-60 days after castration, a significant reduction of the volume of the acini and the duct system as well as a significant increase of the connective tissue volume per cubic millimeter of the gland were noted. The volume and length of the intercalated and the striated ducts per cubic millimeter of parotid tissue are significantly reduced 45-60 days after orchiectomy. Excretory ducts seem to be unaffected by orchiectomy. The structure of the rat parotid acini is also changed by castration, indicating a reduction of acinar-cell activity. In controls, the volume of acinar cells with wide cisternae of rough endoplasmic reticulum is 3 times larger than the volume of acinar cells with regular and narrow cisternae of rough endoplasmic reticulum. After orchiectomy, the volume of acinar cells with wide cisternae of rough endoplasmic reticulum is significantly decreased, while the volume of acinar cells with regular and narrow cisternae of rough endoplasmic reticulum is significantly increased. Exogenously given testosterone can prevent or alleviate the mentioned effects of orchiectomy on the gland. It is concluded that orchiectomy affects the rat parotid gland, demonstrating the existence of an interaction between the testis and the mammalian parotid gland.

Animals↗
PubMedDate not supplied

[Development of peritubular myoid cells in the rat testis].

In the testes of 47 embryos, fetuses and newborn rats (Fisher strain), until the 15th day of life, the appearance and numerical dynamics of "premyoid" and myoid cells were analysed by light microscopy. The material was prepared routinely (fixed in Bouin fluid, embedded in paraffin, and cut to the thickness of 7 micrometers). The embryos of the 12th to 17th day of gestation were serially sectioned in toto, while fetal testes on the 18th to 21th day of gestation were removed and serially cut as well as the rat testes after birth. In each testis ten seminiferous tubules (cords) sectioned perpendicularly were analysed and only in two testes was it possible to find out nine but not ten perpendicularly sectioned tubules. Until the first week after birth, the lengthened cells that envelope tubules (cords) are called "premyoid". In the second half of the second week two types of lengthened cells in the envelope could be seen: one with a very thin, dark nucleus and the other with a lighter and thicker nucleus located peripherally, toward the interstitium. The former are considered myoid cells and the latter as fibroblasts. The numerical dynamics of "premyoid" and myoid cells evidently depends on the "pulsatile" effect of gondotropins. In the prenatal period, it was possible to see two increases in the number of these cells: on the 16th and on the 20th day.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[Sertoli cell secretion].

The article deals with the secretion of Sertoli cells. Different substances they secrete and their role in the testis are described. These cells release a number of factors in their environment, thus creating a local "milieu" and exerting a local control of spermatogenesis in the seminiferous tubules. As target cells for FSH and testosterone, Sertoli cells are also included in a systemic control of spermatogenesis, and because of that, they are necessary for the normal function of the male sex gland.

Animals↗
PubMedDate not supplied

[Gonocytes in the fetal and early postnatal period (stereologic study)].

The behaviour of gonocytes from the 15th prenatal to the 6th postnatal day was studied in testicles of 32 Wistar rats. Histological and cytological methods were applied. Cytological smears were obtained by the imprint method. It was established that the number of gonocytes per cubic millimeter of the tissue for the postnatal group of rat testicles was seven times smaller in respect to the postnatal group. It was 102,338 +/- 15,903 mm0/mm3 for the prenatal group and 13,783 +/- 2538 mm0/mm3 for the postnatal group. The number of gonocytes in the first investigated prenatal day (the fifteenth day) in comparison with the last postnatal day (the sixth day) was even thirty times smaller (i.e. 157,800 against 4,900 mm0/mm3). This work is the first to give morphologic and quantitative data on gonocytes in cytologic smears.

Animals↗