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Biomedical subjects

A F Holstein

Publications and source records attributed to A F Holstein.

At least 19 recordsLinked to original sources
PubMed1995

Expression of the small proteoglycans biglycan and decorin in the adult human testis.

The genes coding for the core proteins of the small chondroitin sulfate/dermatan sulfate proteoglycans (PGs) biglycan and decorin are both expressed in the adult human testis. Northern hybridization of human testicular mRNA indicated the presence of one specific transcript for biglycan at 2.6 kb and two specific transcripts for decorin at 1.6 kb and 1.9 kb. In situ hybridization localized the mRNA for biglycan to the peritubular tissue as well as to the tunica muscularis and adventitia of arteries. Leydig cells and cells of the seminiferous epithelium both proved to be negative. For decorin mRNA, strong signals were found over single, dispersed interstitial cells (possibly fibroblasts), the adventitious layer of large arteries, and the perivascular tissue cells of small arteries, arterioles, and capillaries. In the peritubular cell layers, decorin gene expression was comparably lower and was restricted to the outer fibroblast layers. Germ cells and Sertoli cells were devoid of any positive signal. Immunoblot analysis using specific antisera directed against the core proteins of biglycan and decorin confirmed their presence in chondroitin ABC lyase-treated proteinaceous extracts of the human testis. Immunohistochemistry for biglycan showed a good spatial correlation with the in situ hybridization data and revealed in addition a nonuniform distribution of the antigenic material, which was located predominantly over peritubular myoid cells and the adventitious layer of arteries. Together these results indicate that the expression of both genes in the human testis is differentially regulated, despite the overall similarity of their protein products, and suggest distinct roles for these PGs in testicular function.

Base Sequence↗
PubMed1995

Nitric oxide synthase (NOS-I) in Leydig cells of the human testis.

By means of immunocytochemical methods, immunoreactivity for the brain isoform of nitric oxide synthase (NOS-I) was recognized in numerous Leydig cells of the human testis as well as in MA-10 tumor and TM3 non-tumor mouse Leydig cell lines. Within the Leydig cell cytoplasm, immunocytochemical results suggested the occurrence of factors known to activate NOS-I such as glutamate and aspartate, as well as molecules involved in the regulation of the NOS-I activity such as calmodulin and Ca2+/calmodulin-dependent protein kinase II. Leydig cells, Sertoli cells, some endothelial cells of the testis, MA-10- and TM3 mouse Leydig cell lines exhibited a relatively strong NADPH-diaphorase enzyme activity as well. Double sequential immunostainings provided evidence that NOS-like immunoreactivity of the testicular Leydig cells is colocalized with testosterone, calmodulin, aspartate, glutamate, and Ca2+/calmodulin-dependent protein kinase II. Sodium nitro-prusside treatment did not result in increased cGMP formation by MA-10- or TM3 mouse Leydig cells, suggesting that NO produced by these cells acts primarily in a paracrine fashion. The NO produced by NOS-I immunoreactive Leydig cells may act as a messenger: 1) between neighbouring NOS-I positive and/or negative Leydig cells as well as to mediate the action of numerous intracellular and extracellular neuroactive substances and growth factors; 2) between Leydig cells and the muscle cells or pericytes of blood vessels to regulate local blood flow and permeability; and 3) between Leydig cells and pertibular myofibroblasts to influence their contraction and the permeability of the lamina propria.

Adult↗
PubMed1992

Further practical experiences in the recognition and management of carcinoma in situ of the testis.

99 biopsies from the contralateral testis in patients with unilateral germ cell tumor were investigated using the semithin section technique. Four cases (4%) revealed a carcinoma in situ (CIS) pattern. Two patients underwent a local radiation (20 Gy), 2 patients received combination chemotherapy (cisplatin, etoposide and bleomycin; PEB). No tumor cells were found in control biopsies 4-8 months after therapy. Both biopsy specimens taken from radiated patients lacked also germ cells. In contrast, 1 patient who was treated with PEB and also another 1 presenting with a teratocarcinoma of apparently retroperitoneal origin and unilateral CIS revealed germ cells after chemotherapy. The present data suggest radiation therapy to be the first line treatment for CIS-bearing testes. In order to get informations about the distribution of CIS cells in the affected testes, one or two biopsies were additionally taken from macroscopically unsuspicious tissue surrounding various solid germ cell tumors (74 patients). 56 cases (76%) revealed CIS. Even considering the possibility of missing CIS, a screening biopsy is actually the only method for detecting early manifestations of germ cell tumors and should be performed routinely in contralateral testes of patients with germ cell tumors.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Different epithelia in the distal human male urethra.

The distal segment of the human male urethra, in particular the fossa navicularis, was studied with light- and electron microscopy as well as by means of histochemical and immunocytochemical methods. The fossa navicularis of the urethra contains a circumscribed zone of extremely thick, non-keratinized stratified squamous epithelium composed of cells containing a large amount of glycogen. These cells lack acid phosphatase activity and lysozyme-like immunoreactivity, both of which can be demonstrated to varying extents in the other zones of the distal male urethra. These glycogenrich cells are considered to be the substrate for an endogenous flora of lactobacteria, whereas the acid-phosphatase activity and the lysozyme-like immunoreactivity indicate the presence of macrophages and the secretion of bactericidal agents at the epithelial surface. These observations suggest that the different zones with heterogeneous properties in the distal male urethra probably represent a defense system against the invasion of pathogenic microorganisms. Moreover, the glycogen-rich zone, which resembles the glycogen-rich epithelium of the vagina, is estrogen-dependent. This is demonstrated in cases of sex reversal in which after long-lasting estrogen treatment the glycogen-rich zone becomes extremely extended by displacement of the neighbouring epithelium.

Adolescent↗
PubMed1991

Carcinoma-in-situ cells in cultured human seminiferous tubules.

For the first time, early germ-cell derived tumour cells were studied in an in-vitro system of cultured seminiferous tubules. The intratubular tumour cells not only survived in culture for 7 days but were also able to multiply. Dividing tumour cells were identified in semi-thin sections and electron micrographs by morphological criteria. Additionally, mitotic activity was demonstrated by [3H]thymidine histo-autoradiography. There are numerous reports on cell lines established from solid non-seminomas, but up to now no references to seminoma cell lines or cultures of intratubular tumour cells are available. The culture of seminiferous tubules offers a tool in making carcinoma-in-situ cells accessible for experimental work.

Autoradiography↗
PubMed1990

[Open lymph vessels of the ligamentum falciforme hepatis in the human].

The falciform ligament and the ligamentum teres of the liver are the so-called ventral mesohepaticum. These ligaments are covered on both sides by one layer of mesothelial cells and consist of a dense network of lymphatic capillaries. Preparations of semithin sections were examined light microscopically, ultrathin sections by means of transmission electron microscopy and gold sputtered surface preparations by scanning electron microscopy. It could be shown for the first time that in the mesothelial cell surface there are so-called "stomata", holes which are considered to be connections between the peritoneal cavity and lymphatic capillaries. This network of lymphatics is able to rapidly absorb fluids and particles like blood cells. The knowledge of localisation, structure and function of the submesothelial lymphatic system is of high importance for surgical processing, because in most infections and tumor diseases it is also affected.

Basement Membrane↗
PubMed1990

Cellular architecture of the lamina propria of human seminiferous tubules.

The lamina propria of human seminiferous tubules is composed of 5 to 7 cellular layers separated by laminae of extracellular connective-tissue components. By means of immunocytochemical methods the different nature of the cellular layers could be defined for the first time. Based on the light-microscopic demonstration of both desmin-like and vimentin-like immuno-reactivity in the inner 3 to 4 layers of the lamina propria, these cells can be identified as myofibroblasts. The outermost one or two cellular layers, on the contrary, only show a vimentin-like immunoreactivity indicating the pure fibroblastic nature of these cells. Therefore, the outermost cellular layers are suggested to be derivatives of the interstitium. In cases of disturbed spermatogenesis, the lamina propria is frequently considerably thickened by an increase in the extracellular matrix components between the cellular layers. Whereas the ultrastructural localization of laminin-, collagen type-IV- and fibronectin-like immunoreactivity remains unaffected in the thickened lamina propria, the desmin-like immunoreactive cells of the inner layers strongly decrease in number and staining intensity. Most probably, the myofibroblasts lose their myoid characteristics to participate in the secretion of increased amounts of extracellular matrix components, which in turn presumably block the mediation of the lamina propria between the interstitium and the germinal epithelium. It is still unclear whether the thickened lamina propria provokes the disturbance of spermatogenesis or vice versa.

Aged↗
PubMed1990

Organ culture of human seminiferous tubules: a useful tool to study the role of nerve growth factor in the testis.

Seminiferous tubules from human testes were mechanically isolated, the cut edges were sealed, and the tubules were cultured in medium free of fetal calf serum (FCS). Degeneration of germ cells occurred during the culture period and was paralleled by a disruption of the seminiferous epithelium, a disturbance in morphology and function of Sertoli cells, and a thickening of the lamina propria. However, when tubules were cultured for 5 days in the presence of FCS, degeneration of the spermatogenic tissue was reduced. FCS increased the mitotic activity of germ cells, but did not maintain normal morphology and function of Sertoli cells and cellular elements of the lamina propria. The thickening of the tubular wall concurred with a change in phenotype of lamina-propria cells from myoid to fibroblastic. Addition of nerve growth factor (NGF) to the culture medium (i) maintained the myoid phenotype of lamina-propria cells, (ii) prevented thickening of the tubular wall, and (iii) stabilized Sertoli cell morphology and function. The effects of NGF appeared to depend on the trophic effects of FCS, since NGF alone had no influence on the maintenance of a regular morphology of the spermatogenic epithelium. The present results indicate a decisive role for NGF in stabilizing specific functions of seminiferous tubules.

Aged↗
PubMed1990

Evidence for the presence of nerve growth factor (NGF) and NGF receptors in human testis.

Nerve growth factor (NGF) affects morphology and function of isolated and cultured seminiferous tubules from human testis. Quantitative determination of this neurotrophic protein revealed an amount of 5.4 ng per g human testis, suggesting a crucial function of NGF in spermatogenic tissue. With the use of immunohistochemical methods target cells for NGF were identified within the lamina propria. NGF receptors were also visualized on sympathetic nerve fibers crossing the interstitial compartment among adjacent tubules and spatially correlated blood vessels. NGF receptors could be demonstrated on isolated lamina-propria cells even after 2 weeks of culture. Most of the NGF receptor-bearing cells differed from myoid cells of the lamina propria expressing desmin, a marker for smooth muscle. However, some NGF receptor-expressing cells were found sharing morphological and structural similarities with myoid cells. The present data indicate the existence of a NGF-responsive lamina-propria cell that influences the tubular wall and also the seminiferous epithelium.

Humans↗
PubMed1990

Chronological and structural disorder of the spindle-shaped body during human spermatid differentiation.

In a testicular biopsy of an infertile man, most of the spermatids revealed a lack of the middle piece because of a malformed or untimely occurring spindle-shaped body. When during spermatid differentiation the spindle-shaped body appeared, it contained the typical bundles of tubules but was often reduced in size and arranged only unilaterally to the axoneme. After the disappearance of the incomplete spindle-shaped body, the annulus did not descend, the ribs of the fibrous sheath of the principal piece were found far proximally and the mitochondrial sheath of the middle piece could not be formed. In consequence of this faulty development, the spermatozoa were immotile.

Adult↗
PubMed1989

Leydig cell mitoses in human testes bearing early germ cell tumors.

Numerous mitoses were noted in testicular tissue from adult men with early germ cell tumors. More than 15 Leydig cells undergoing mitosis were found in the interstitial compartment. The presence of specific crystalline intracytoplasmatic inclusions demonstrated for the first time that differentiated Leydig cells are capable of proliferation. Occasionally cells are difficult to discriminate during mitosis. To establish reference criteria, the light- and electron-microscopic features of the following mitotic cells were examined: Leydig cells, fibroblasts, perivascular cells, peritubular cells, and lymphocytes. Supplementary mitoses in germ cell tumors and in a case of Leydig cell tumor were investigated. In the literature, only single reports of mitoses in Leydig cells are available. The frequent incidence of Leydig cell mitosis in early germ cell tumors may be due to the presence of growth-promoting factors in the testicular tissue.

Adult↗
PubMed1989

Carcinoma in situ of the testis in the presence of contralateral germ cell tumor.

Carcinoma in situ (CIS) of the testis is considered a precursor of germ cell tumor. Diagnosis is made by biopsy, a procedure which is justifiable for patients with increased tumor risk. This group includes patients with testicular tumors who may develop contralateral second malignancies. After obtaining contralateral biopsies from 21 such patients we found one CIS. Treatment consisted of local irradiation (20 Gy) of the remaining testis. No clinical side effects were observed. In a control biopsy 6 months later, no evidence of CIS was found. Leydig cells were morphologically normal. Nine months after therapy, plasma testosterone levels were still normal, LH and FSH levels were increased. Long-term observations are needed to assess the value of radiotherapy as compared to orchiectomy.

Adult↗
PubMed1989

[Early detection of a contralateral second carcinoma in patients with testicular tumors caused by testicular carcinoma in situ].

Carcinoma in situ (CIS) of the testis is considered to be a precursor of germ cell cancer. Diagnosis is made by the conventional biopsy technique. Only for patients at risk is a screening biopsy justifiable. This group includes patients with testicular cancer in whom the incidence of contralateral second germ cell tumors is increased. In a prospective study we found three cases of testicular CIS in biopsies from the contralateral testes of 61 such patients. All cases with a diagnosis of CIS presented with testicular atrophy (volume less than 12 ml), associated with necrozoospermia in one patient and with azoospermia in two patients. Treatment consisted in local irradiation (20 Gy) of the remaining testis to preserve Leydig cell function. In control biopsies no evidence of CIS or germ cells was found. More than 3 months after therapy, plasma testosterone levels were normal and LH and FSH levels were increased. None of the patients with negative biopsy (n = 49) who were followed up was found to have a second cancer of the contralateral testis. The average observation time so far is 17.2 months.

Biopsy↗
PubMed1987

Morphology of normal and malignant germ cells.

By means of semithin section histology and electron microscopy the following male germ cells are described: gonocytes and prospermatogonia in the embryonic and fetal testes; spermatogonia and primary spermatocytes in the testis of the adult; abnormal spermatogonia and spermatocytes, which are not tumour cells. In contrast to these cells, four main tumour cell types which on the basis of morphological criteria can be said to be derived from germ cells, are classified and designated as Tc 1 to Tc 4. The various tissues accompanying the tumour cells are briefly described.

Humans↗
PubMed1987

Are Leydig cells of neural origin? Substance P-like immunoreactivity in human testicular tissue.

Using the immunocytochemical peroxidase-antiperoxidase method we observed strong and selective staining of Leydig cells after incubation of human testicular tissue with an antiserum against substance P and a slightly weaker immunoreactivity against methionine-enkephalin. These results indicate that the embryologic origin of Leydig cells may require reconsideration and also offer a new perspective for research upon the local control mechanisms of spermatogenesis.

Adult↗
PubMed1987

[Morphology of syncytiotrophoblast cells in testicular tumors].

Syncytiotrophoblastic cells were identified in a teratocarcinoma of the testis by light microscopy using the semi-thin sectioning technique. An electron microscope study confirmed them to be syncytial. Many irregularly shaped nuclei lying in a honeycombed cytoplasm were observed, while the free margins contained microvilli. These cells are morphologically similar to syncytiotrophoblasts of the normal placenta. The presence of syncytiotrophoblastic cells in testicular tumours means a worse prognosis than would otherwise be concluded on the basis of the particular tumour concerned.

Chorionic Gonadotropin↗