Endothelin-1 and its receptors in the human epididymis.
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Endothelin-1↗
Biomedical subjects
A F Holstein
Publications and source records attributed to A F Holstein.
Nitric oxide/cGMP pathway components in the Leydig cells of the human testis.
In this study we sought to determine whether the main components of the nitric oxide (NO) pathway are localized within the Leydig cells of the human testis and whether the soluble guanylyl cyclase (sGC), the enzyme that accounts for NO effects, is functionally active in these cells. Using an amplified immunocytochemical technique, immunoreactivity for nitric oxide synthase (NOS-I), sGC and cyclic guanosine monophosphate (cGMP) was detected within the cytoplasm of human Leydig cells. Distinct differences in staining intensity were found between individual Leydig cells, between cell groups and between Leydig cells of different patients. By means of a specific cGMP-RIA, a concentration-dependent increase in the quantity of cGMP was measured in primary cultures of human Leydig cells following exposure to the NO donor sodium nitroprusside. In addition, NOS-I immunoreactivity was seen in Sertoli cells, whereas cGMP and sGC immunoreactivity was found in Sertoli cells, some apically situated spermatids and residual bodies of seminiferous tubules. Dual-labelling studies and the staining of consecutive sections showed that there are several populations of Leydig cells in the human testis. Most cells were immunoreactive for NOS-I, sGC and cGMP, but smaller numbers of cells were unlabelled by any of the antibodies used, or labelled for NOS-I or cGMP alone, for sGC and cGMP, or for NOS-I and sGC. These results show that the Leydig cells possess both the enzyme by which NO is produced and the active enzyme which mediates the NO effects. There are different Leydig cell populations that probably reflect variations in their functional (steroidogenic) activity.
Adult↗
Occurrence of enzymes of free radical metabolism suggests the possible cytotoxic capacity of the transitional epithelium of the human ureter.
Three enzymes, viz., tartrate-resistant acid phosphatase (TRAP), nitric oxide synthase I (NOS-I), and superoxide dismutase (SOD), involved in the production and metabolism of free radicals or radical equivalents, were demonstrated by immunocytochemistry in the urothelium of the ureters of six patients of various ages. Two of these enzymes (TRAP and NOS-I) were colocalized in the most apical and lateral border of the superficial cells of the urothelium. In contrast, SOD showed a patchy or granular distribution within the supranuclear region of these cells. Intra- and subepithelial macrophages exhibited a weak TRAP, but no NOS-I or SOD, immune reaction. On the basis of the immunocytochemical findings, arguments in favor of a cytotoxic function of the superficial cells of the human urothelium are presented.
Acid Phosphatase↗
Evidence for production and functional activity of nitric oxide in seminiferous tubules and blood vessels of the human testis.
Previous studies have demonstrated that nitric oxide (NO) influences Leydig cell function. Here we provide evidence for NO production and activity in seminiferous tubules and blood vessels of the human testis. By immunohistochemistry, the soluble guanylyl cyclase (sGC), the intracellular NO receptor, and the second messenger, cyclic guanosine monophosphate (cGMP), were detected in myofibroblasts of the peritubular lamina propria in Sertoli cells, as well as in endothelial and smooth muscle cells of testicular blood vessels. Performed with isolated tubules and blood vessels, the biological activity of sGC could be proved by cGMP generation in response to treatments with the NO donor, sodium nitroprusside. The endothelial and neuronal subtypes of NO synthase (NOS) were localized immunohistochemically to the same cell types that express sGC and cGMP. In isolated tubules and vessels, the presence of endothelial NOS and neuronal NOS was confirmed by immunoblotting, and NOS activity was demonstrated by decreased cGMP production upon incubation with the NOS inhibitor L-nitro arginine methylester. These findings show that peritubular cells, Sertoli cells, and testicular blood vessels may be sites of NO production and activity, possibly involved in relaxation of seminiferous tubules and blood vessels to modulate sperm transport and testicular blood flow, respectively.
Adult↗
Capillaries in the lamina propria of human seminiferous tubules are partly fenestrated.
The three capillary parts of the microvasculature of the human testis, namely the arterial side inter-Leydig cell capillaries, the intramural capillaries, and the venous side inter-Leydig cell capillaries, were studied in detail by dual detection of alkaline phosphatase enzyme activity and endothelial marker immunoreactivity, and by means of light- and transmission-electron microscopy. Alkaline phosphatase enzyme activity was seen in intertubular arterioles, capillaries, and venules, and in intramural capillaries of the human testis, whereas the lamina propria of human seminiferous tubules showed no staining. Alkaline phosphatase enzyme activity and the endothelial marker detected by the Qbend 30 antibody co-existed within the endothelial cells of the microvasculature. Electron-microscopically, the endothelial cells of the arterial and venous side inter-Leydig cell capillaries, and of the intertubular capillaries free of Leydig cells were of the continuous type without fenestrations (A-1-alpha type). The intramural capillaries consisted of non-fenestrated (A-1-alpha type) and fenestrated sections (A-2-alpha type). The fenestrations faced the germinal epithelium. Capillaries with a continuous non-fenestrated endothelium contained a large number of transcytotic vesicles and channels. These were numerous in the endothelial cells of the inter-Leydig cell capillaries and the non-fenestrated part of the intramural capillaries. Capillaries partly ran in between the layers of the lamina propria and therefore represented the capillarization of the seminiferous tubules. Thus the multilayered lamina propria probably requires its own capillary supply to allow rapid exchange between the microvasculature and the epithelium of the human seminiferous tubules.
Arterioles↗
The influence of temperature on changes in pH, lactate and morphology during testicular ischaemia.
OBJECTIVE: To examine the role of temperature in the irreversible changes that occur within 4-6 h as ischaemic atrophy develops in the testis during testicular torsion, by determining effects on testicular pH, lactate accumulation and morphology. MATERIALS AND METHODS: Tissue acidification (pH), tissue lactate and structural changes were measured at temperatures of 35, 25, 15 and 5 degrees C in 34 human testes obtained as orchidectomy specimens from patients with metastatic prostatic cancer, and in 19 testes taken from young dogs. RESULTS: At a normal testicular temperature of 35 degrees C, the pH decreased to 6.0 within 2 h of the onset of ischaemia; cooling to 15 degrees C extended this delay to 6 h. Tissue lactate increased from 25 mumol/g dry weight to about 200 mumol/g at 35 degrees C. Semi-thin sections of the canine testes showed swelling of the intratubular tissue with loss of interstitial space; lower temperature delayed these changes. CONCLUSIONS: In the present study, 6 h of torsion was relatively prolonged, in that the pH decreased to 5.8 and testicular tissue was destroyed. Acidification and histological damage can be prevented by cooling. The critical pH of the testis beyond which irreversible changes occur is unknown; a pH of < 6.0 is likely to provoke such changes.
Aged↗
A new concept for the extraction of testicular spermatozoa as a tool for assisted fertilization (ICSI).
A new method is described for the enzymatic preparation of testicular tissue to obtain vital spermatozoa for ICSI. The tissue obtained from both testes by biopsy is studied by means of the semi-thin section method as well as being cryo-preserved. If spermatid formation is assured by semi-thin section histology, vital spermatozoa from the cryo-preserved portion of testicular tissue are enzymatically prepared. In this way it is possible to optimize the reproductive medical treatment for those couples in whom an extracorporal fertilization of oocytes by means of testicular spermatozoa is being considered.
Aged↗
Histologic diagnostics of early testicular germ-cell tumor.
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Carcinoma in Situ↗
Myofibroblasts in the lamina propria of human semi-niferous tubules are dynamic structures of heterogeneous phenotype.
Myofibroblasts of the lamina propria of human seminiferous tubules were studied in testes having normal or slightly reduced spermatogenesis by means of electron microscopy, confocal laser microscopy and immunocytochemistry. Myofibroblasts are large, flat individual cells braced in a network of microfibrils and collagen fibrils in the tubular wall. They are arranged in discontinuous cell layers with interposed layers of an extracellular matrix. Myofibroblasts of the lamina propria exhibit an unique cell shape with the peripheral cytoplasm split up in two or more layers. After FITC-phalloidin staining and by means of confocal laser microscopy, actin filaments of variable orientation are visible in their cytoplasm. The thickness and preferential direction of actin filaments differ in the outer and innermost cell layers. The myofibroblasts express both antigens of smooth muscle cells (alpha-smooth muscle actin, pan-actin, desmin, GB 42, smooth muscle myosin), and of connective tissue cells (vimentin, fibroblast surface protein). The variable expression of these antigens evidenced the existence of different phenotypes of myofibroblasts. Immunoreactivity for basic fibroblast growth factor and transforming growth factor beta as well as for components of the extracellular matrix indicate that these agents may be important for the phenotypic differentiation of the lamina propria cells. The detection of CNPase-and galactocerebroside-immunoreactivity in a number of lamina propria cells and some cells of the intertubular tissue gives rise to the hypothesis that components of the testicular tissue share some structural similarities with glia cells of the nervous system. Finally, immunoreactivities for the neuronal and endothelial nitric oxide synthase, soluble guanylyl cyclase, cyclic GMP, calmodulin, calcium-dependent protein kinase II and glutamate indicate that the contractility of myofibroblasts in the lamina propria of human seminiferous tubules may be in part modulated by the NO/cGMP-system.
Aged↗
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↗
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↗
Reinvestigation of the transitional epithelium (urothelium) of the human ureter.
The transitional epithelia (urothelia) of the ureters of 30 patients of different ages were studied by means of light and electron microscopical, histochemical and immunocytochemical methods. A great variability of the normal structural appearance of the urothelium was established. Structural features and the uptake of exogenous peroxidase by the surface epithelial cells provided high endocytotic activity. Urothelial cells take up many low and high molecular weight substances from the urine and further metabolize and transport these toward the subepithelial connective tissue. Lymphocytes, macrophages, monocytes, plasma cells and rarely polymorphonuclear leukocytes are distributed intra- and extraepithelially and are involved in the immunological response to agents which enter the intercellular spaces of the epithelium. These cells are also responsible for the elimination of aged and degenerating superficial squamous cells. The present investigation establishes the existence of immunological defence mechanisms in the adult human urothelium. The results obtained suggest that the human ureter contains three functional barriers directed against aggressive components of the urine: the first represented by structures of the superficial squamous cells, the second by the upper cells of the ureteric intermediate layer and the third comprising epithelial and immunological cells involved in immune defence mechanisms.
Adult↗
The Leydig cell of the human testis--a new member of the diffuse neuroendocrine system.
A number of marker substances for neuronal and neuroendocrine cells have been demonstrated in the cytoplasm of the interstitial Leydig cells of human testes using basic immunocytochemical methods and some of their modifications. We were able to reveal immunoreactivity for enzymes involved in the synthesis of the catecholamines dopamine and noradrenaline (tyrosine hydroxylase, aromatic L-amino acid decarboxylase, dopamine-beta-hydroxylase), for the indolamine 5-hydroxytryptamine (serotonin), as well as for a number of well-known neuronal markers such as the neurofilament protein 200, synaptophysin, chromogranin A + B, the neural cell-adhesion molecule (N-CAM), the microtubule-associated protein (MAP-2), and the calcium-binding proteins: S-100, calbindin and parvalbumin. Immunoreactivity for these substances was found in the majority of the interstitial cells although differences in the staining intensity among the individual Leydig cells and among Leydig cells from different patients were observed. At the electron-microscopic level the Leydig cell cytoplasm was seen to contain microtubules, intermediate- and microfilaments as well as clear (40-60 nm) and dense-core (100-300 nm) vesicles, providing a morphological correlate for some of the immunocytochemical results. Although individual marker substances are not absolutely specific for nerve and neuroendocrine cells, the results obtained, together with the already established neuron-specific enolase-, substance P-, methionine-enkephalin- and proopiomelanocortin (POMC)-derived peptide-like immunoreactivity, provide strong evidence for the neuroendocrine (paraneuronal, APUD-like) nature of the Leydig cells of the human testis.
Adult↗
Cellular components of early testicular cancer.
Different types of tumor cells can be described by means of the semithin section method, immunocytochemistry and transmission electron microscopy. They are situated intratubularly in the basal and adluminal compartment of the germinal epithelium, in the interstitium, and in the solid seminoma. Also teratoma cells can be identified within the seminiferous tubules. Their occurrence together with tumor cells, rich in glycogen (Tc 1), in the same area of a seminiferous tubule, supports the suggestion that seminomata and teratomata originate from the same tumor cell type. Macrophages may be an essential constituent of the early forms of testicular tumors. They are able to invade seminiferous tubules, there to lyse tumor cells and to phagocytose them in fragments. The different participation of the particular cell systems in a testicular tumor is decisive for its organization and presentation.
Carcinoma in Situ↗
[In memoriam Edward C. Roosen-Runge].
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Anatomy↗
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↗
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↗
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↗