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Biomedical subjects

A F Holstein

Publications and source records attributed to A F Holstein.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1987

[Connective tissue framework of the greater omentum].

Tissue samples of the greater omentum were intraoperatively collected from 17 patients on whom laparotomy was performed for different indications. The connective tissue framework of the unstained omentum was investigated, using a stereomicroscope. Histological sections were prepared from large saw-cuts of the plastinated omentum. The greater omentum of man was found to possess a connective tissue framework with blood and lymphatic vessels and was also found to be embedded in adipose tissue. The latter is made up of fatty organs differentiated in size. Round to oval organs are formed by fat cells. These organs are delimitated from their environment by a tender connective tissue capsule and are connected, through a pedunculated structure, to a vascular cord of the connective tissue framework. Connective tissue fibres radiate from the framework into the capsule which is made up of a submesothelial connective tissue layer and the mesothelium. The peduncle of a fatty organ consists of connective tissue as well as of supplying blood and lymphatic vessels. Fatty organs surrounded by connective tissue fibres were visualised even in highly adipose regions by means of plastinated saw-cuts of the greater omentum.

Adipose Tissue↗
PubMed1986

Dissociated centriole development as a cause of spermatid malformation in man.

Ultrastructural study of a testicular biopsy from an infertile man with decapitated spermatozoa revealed a hitherto undescribed type of malformation. It was caused by a dissociation between the proximal and distal centrioles during the first steps of spermatid differentiation. The disconnection probably occurred because of the lack of striated columns in the connecting piece. Up to 40% of the separately developed and released tails showed a normal motility in the ejaculate.

Cell Differentiation↗
PubMed1986

[Spermatogenesis in the aged--a borderland between normal and pathologic anatomy].

Aging of the testis is a normal physiological process, which gradually proceeds with increasing age. Under normal conditions, an abrupt breaking off the spermatogenetic and hormonal functions of the testis does not occur. Already in the testis of every adult fertile man single degenerating germ cells are recognizable, the occurrence of which is understood as physiological germ cell loss. In men, older than 65 years, further degenerative changes of the germ cells and of the germinal epithelium regularly can be found, which have negative effects on the spermatogenetic activity of the germinal epithelium. These changes concern disturbances of the kinetics of spermatogenesis, disturbances of spermatogoniogensis and of meiosis, malformations of the spermatids, the release of immature germ cells from the germinal epithelium, the concentration of lipids within the Sertoli cells, the appearance of diverticles of the seminiferous tubules and possibly also atrophy of seminiferous tubules. In the course of regular testicular aging these degeneration phenomena can be observed to a relatively small extent diffusely distributed in the testis and exhibiting individual differences. A phatological alteration of the testicular tissue is under consideration as soon as a definitive pattern of damage predominates in the whole organ or when a focal degeneration of testicular tissue has appeared. The borderland between normal and pathological anatomy of testis tissue during aging is characterized.

Aged↗
PubMed1985

Morphogenesis and fate of the residual body in human spermiogenesis.

In the human testis the formation of the residual body of the spermatid and its morphological changes during and after spermiation were studied by means of electron microscopy. The caudal cytoplasmic mass of the late spermatid contains a Golgi complex, mitochondria, annulate lamellae, a chromatoid body, flower-like structures, ribosomes, a few large vacuoles, myelin-like membrane profiles and sporadic lipid droplets. When, by detachment of the caudal cytoplasm from the free spermatozoon, the residual body is formed, the chromatoid body has disappeared; the mitochondria are clustered peripherally; the ribosomes appear as a single complex in contact with a large vacuole containing granular material; in place of the Golgi complex aggregations of vesicles are present. The lipid droplets remain unchanged. The residual bodies or their fragments are either extruded via the seminiferous tubular lumen into the excurrent ducts or they are engulfed by Sertoli cells where in the supranuclear region the successive steps of decomposition can be observed. The participation of the various constituents in the disintegration of the residual body is discussed. In contrast to other mammalian species, in man the sporadic lipid droplets seem to be of minor importance in the fate of the residual body.

Adult↗
PubMed1985

[The surface of the greater omentum in the human and its vulnerability in intra-abdominal surgical interventions].

From five patients of the Department of General Surgery of the University Hospital of Hamburg-Eppendorf, who underwent laparotomy because of different indications, small pieces of tissue of the greater omentum were taken intraoperatively. The surface morphology of the greater omentum was studied by means of light, transmission electron and scanning electron microscopy. It became obvious that intact tissue only was obtained when the procedure of taking out material was accomplished most carefully. Consequently, during normal surgical manipulations the greater omentum usually will be damaged. In undamaged tissue specimen the normal surface of the greater omentum in man is described. The findings basically confirm the results of previous investigations. Injuries at the surface of the greater omentum after surgical treatment are, however, much more severe than they are noticeable by the naked eye. Lifting up of the mesothelium, ruptures of the submesothelial structures of connective tissue, squashing of fat cells and ruptures of blood vessels can be observed. During these processes lipid droplets are squeezed into the submesothelial connective tissues or even pressed up to the surface of the mesothelium. Large quantities of erythrocytes are found in the interstitium in between the adipose cells. To what extent milky spots and free nerve endings at the surface of the greater omentum are damaged during intraoperative manipulations cannot be unequivocally estimated on the basis of the material studied here.

Abdomen↗
PubMed1985

[Spermatogenesis in patients with traumatic transverse paralysis].

Testicular biopsies from 22 paraplegic men were studied by light and electron microscopy. The investigations of semithin sections by a special standardized method revealed that normal spermatogenesis occurred in only one patient, whereas in 21 patients severe disturbance of spermatogenesis was found. The germinal epithelium displayed a decrease of spermatogenic cells, an increase of degenerating cells, especially of spermatids, and a release of large groups of premature germ cells. Cross sectioned tubules often showed no patent lumina. As revealed by electron microscopical investigations the spermatids show malformations in most cases of the head and acrosome, rarely of the tail. Decreased spermatogenic activity occurred in various degrees in each of the 21 men. There is no evidence that any specific form of spermatogenic disturbance exists typical of spinal cord injury. No obvious relationship was found between the degree of spermatogenic disturbance and duration or level of the spinal cord lesion or incidence of urinary tract infection.

Adult↗