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Biomedical subjects

A F Holstein

Publications and source records attributed to A F Holstein.

At least 127 records · Page 7Linked to original sources

Spermatophagy in the seminiferous tubules and excurrent ducts of the testis in Rhesus monkey and in man.

The fine structure of cells capable of phagocytosing spermatozoa in the testes and epididymes of monkeys and men was studied by means of transmission and scanning electron microscopy. Both resident cells, such as Sertoli cells and epithelia of the rete testis, and free cells, such as macrophages (spermatophages) were found to phagocytose spermatozoa or fragments of spermatozoa in the seminiferous tubules and excurrent ducts. The spermatophages develop from precursor cells which invade the seminiferous tubules. After phagocytosis of spermatozoa they increase in size and sometimes possess more than one nucleus. Large spherically shaped spermatophages are found in the epididymis. In the rete spaces of Macaca fascicularis spermatophages are able to penetrate the rete epithelia and reside in the subepithelial connective tissue layers. Spermatophagy is frequently seen in the gonads of older men and in certain cases of oligozoospermia. In Macaca an increased number of spermatophages occurs at the end of the spermatogenetic season.

Animals↗

Leydig cells within the lamina propria of seminiferous tubules in four patients with azoospermia.

Mature, polygonal Leydig cells within the thickened lamina propria of the seminiferous tubules are commonly found in three cases of cryptorchidism and one case of Sertoli-cell-only syndrome. By contrast, under normal conditions Leydig cells between the peripheral layers of the peritubular tissue were only occasionally met in a spindle-shaped variant. In both instances, Leydig cells were positively identified in the electron microscope by characteristic features such as anabundant smooth endoplasmic reticulum, tubular inclusions and crystals of Reinke. The development of Leydig cells from myoid contractile cells within the lamina propria is discussed.

Cryptorchidism↗

Multinucleated spermatocytes and spermatids in human seminiferous tubules.

The cytology of multinucleated spermatocytes and spermatid giant cells in the seminiferous tubules of men with oligozoospermia and of men older than 65 years has been investigated electron microscopically. Two different processes which are responsible for the origin of multinucleated germ cells have been analysed: Defects of the intercellular bridges (IB): they move apart and thus allow the confluence of one clone's cells to symplasms. The confluence of membranes: within one clone the membranes of neighbouring germ cells are dissolved and thus intercellular bridges are found in the cytoplasm of the resulting giant cells. The spermatid giant cells reveal a new organization of the cell nuclei and the cell organelles. Yet they disintegrate in the lumen of the seminiferous tubules. The appearance of giant cells therefore is an expression of the germ cell degeneration.

Adult↗

Megalospermatocytes: indicators of disturbed meiosis in man.

Megalospermatocytes are degenerating primary spermatocytes which do not develop any further than to leptotene stage of the prophase of meiosis. In histological sections they are prominent because of their size (approximately 24 microns in diameter). The nucleus of a megalospermatocyte presents single strands of chromosomes only. The cytoplasm contains extremely widened vesicles and cisternae of the ER which are filled with a finely granular electron dense material. Megalospermatocytes may appear singular in small groups in the testis tissue of young men with varying fertility disturbances. They are relatively frequent in testis tissue of men older than 65 years. Here they represent a special form of a rest of spermatogenetic activity in the germinal epithelium.

Aged↗

Scanning electron microscopic observations on the epithelium of the human prostatic urethra.

The human prostatic urethra has been investigated by means of scanning electron microscopy. On the posterior wall of the urethra, the seminal colliculus with the orifices of the ejaculatory ducts is clearly detectable. The upper portion of the prostatic urethra shows a typical transitional epithelium with large superficial cells of a ruffled appearance. In the lower portion of the organ (underneath the openings of the ejaculatory ducts), the apical pattern of the cells varies considerably. Four main aspects are recognizable: apices provided with microvilli, dome-shaped apices with an almost smooth surface, large apices with labyrinthic microplicae and ciliated apices. Also, apices showing intermediate characteristics can be noted. The functional significance of the morphological patterns as well as the possibility of a transition among the various types of surface structures are discussed.

Aged↗

On the morphology of the transitional zones from the rete testis into the ductuli efferentes and from the ductuli efferentes into the ductus epididymidis. Investigations on the human testis and epididymis.

Transitions from the rete testis into the ductuli efferentes and from the ductuli efferentes into the ductus epididymidis were examined in the epididymes of 4 patients with prostatic cancer aged 65, 72, 77 and 78 years, in the epididymis of a 19 year-old accident victim and in the epididymis of an embryo of the 12th week. Concerning the former area, the results published up to now were confirmed. But according to our examinations, the transition from the ductuli efferentes into the ductus epididymidis is different from what has been described in the literature so far. In the adult human, the ductuli efferentes do not show end-to-side connections with the ductus epididymidis, but end-to-end junctions with "extensions" of the ductus epididymidis which finally join the ductus epididymidis end-to-side. However, in the epididymis of the embryo, one still finds end-to-side connections of ductuli efferentes and the ductus epididymidis. It was concluded that the extensions of the ductus epididymidis are formed during the development of the system of canaliculi in the epididymis from the embryonal stage to adult age.

Adult↗

Processing of testicular biopsies--fixed in Stieve's solution--for visualization of substance P- and methionine-enkephalin-like immunoreactivity in Leydig cells.

In the present report a schedule for processing testicular biopsies fixed in Stieve's solution is described which is suitable for modern immunocytochemical techniques. By means of this procedure the existence of immunoreactivity in Leydig cells can be demonstrated using antisera against substance P and methionine-enkephalin.

Biopsy↗