Biomedical subjects
Publications and source records attributed to E Tabone.
A case of osteosarcoma of the tongue is reported, with microscopic findings. The patient underwent chemotherapy, left hemiglossectomy, and neck dissection, followed by radiotherapy. Five years after initial therapy, he is still alive and well, with no evidence of recurrence.
A series of 120 patients (T2, No, N1a according to UICC classification) with mammary cancer treated by mastectomy and regional lymph node dissection, classified T2N-after Hemalun-Phloxine Safran (HPS) standard sections, have a positive reaction with immunohistochemical staining (IHM) using monoclonal antibodies (anti KL1) so that IHM improve the detection of lymph node metastases. 13 patients out of 120 presumed N-after HPS technic became positive with IHM staining. We examined 2108 lymph nodes and noticed 19 N+, the size of which was less than 2 millimeters. Microscopically, three main aspects are follows. Micrometastases made of clusters of malignant cells; micrometastases with single cells in file, and a composite aspect from both previous ones. Metastatic cells detected by anti KL1 have an excellent contrast due to clear nucleus surrounded by a large rim of dark cytoplasm. Although T2N-has a better prognosis than T2N+, 10 to 20% of patients relapsed within ten years after surgical treatment. It is important to determine whether the detection of occult micrometastases permits to predict recurrence. Is it a relevant correlation or not? if such a connection does'not exist, micrometastasis detection became irrelevant; on the contrary, if it exists, the therapists can launch on adequate adjuvant treatment - useful only - for patients with high risk of relapse.
During long-term venous catheter implantation, septic and thrombotic complications are quite frequent. In the case reported, the failure of systemic and local antibiotic therapy during repeated septicaemia due to Bacillus cereus at the time of intensive chemotherapy led to a scanning electron microscopy study of the used silicone catheter. There were marked changes of the inner surface with a lot of cellular remains, in contrast with the usual non thrombogenic property of the silicone. An in vitro study was carried out with antitumour agents. Duration of exposure and drug concentration were identical to those used in in vivo perfusions. There were marked changes of the inner surface, which could lead to important modifications of the properties of the silicone. The damage depended on the drug. Silicone was slightly sensitive to vicristin and carmustin, but highly sensitive to cisplatin and doxorubicin. The compatibility of catheter material with the drugs used, especially for oncologic chemotherapy, must be tested systematically.
An in vitro study of the effect of cytotoxic drugs on polyurethane catheters was carried out. The drugs used--vincristine, doxorubicin, cisplatin and carmustine--damage the surface of silicone elastomer catheters. The irregularities produced seem to be preferential sites for thrombus formation and adhesion of bacterial microcolonies. Electron microscopy examination of the catheters dipped in the drug solutions for different time intervals revealed the appearance of different patterns of damage. The irregularities produced seemed to be less pronounced than for silicone catheters. Polyurethane was highly sensitive to doxorubicin. These changes could well have clinical repercussions. The compatibility of catheters and drugs should be routinely tested before being put on the market.
Data from several experimental approaches have been reviewed and the findings clearly indicate the existence of multiple interactions between testicular cells and the potential role of these interactions in the paracrine control of testicular functions. Both testicular interstitial fluid and spent media from cultured Sertoli cells had an acute steroidogenic effect on Leydig cells, and this effect is not species specific. The secretion of this steroidogenic factor(s), which is probably a protein, is enhanced by previous FSH treatment of Sertoli cells. Coculture for 2-3 days of pig Leydig cells with homologous or heterologous Sertoli cells enhances Leydig cell specific functions (hCG receptor number and hCG responsiveness) and induces Leydig cell hypertrophy. A similar but less pronounced trophic effect is seen when Leydig cells are cultured with spent media from Sertoli cells cultured in the presence of FSH and high concentrations of insulin, but the spent media from Sertoli cells cultured in the absence of these two hormones inhibits Leydig cell specific functions. Somatomedin-C might play an important role in the positive trophic effect of Sertoli cells on Leydig cells, since this peptide is secreted by Sertoli cells and it has trophic effects on the specific function of Leydig cells. Moreover, Sertoli cells, probably through a diffusible factor and cell-to-cell contacts, control the multiplication, meiotic reduction and maturation of germ cells. In turn, the activity of Sertoli cells is modulated by the stage of neighbouring germ cells. Thus, if a normal Sertoli cell function (which depends not only on FSH but also on Leydig and myoid cell secretory products) is an absolute requirement for germ cell multiplication and maturation, these cells, in turn, cyclically regulate Sertoli cell function and through these cells the size and probably the function of Leydig cells.
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The regulating effect of follicle-stimulating hormone (FSH) on Leydig cell function was studied using a model of immature porcine Leydig and Sertoli cells cultured in a hormone supplemented defined medium. FSH pretreatment for 2 days of Leydig cells cultured alone was with no effect. FSH pretreatment of Leydig cells cocultured with Sertoli cells increases Leydig cell activity in an FSH dose-dependent manner with a maximal effect observed at 50 ng/ml porcine FSH (pFSH). Leydig cells cultured for 2 days in conditioned medium (CM) by FSH stimulated (FSH-CM) Sertoli cells, as compared to CM by unstimulated (control) (C-CM) Sertoli cells show an increase of their activity with a maximal effect observed at 50 ng/ml pFSH. Leydig cells cultured in CM as compared to non CM, show a marked development of organelles (smooth endoplasmic reticulum and mitochondria) involved in the steroidogenic activity. The activity of FSH-CM as compared to C-CM on Leydig cell function was non dialyzable and trypsin sensitive. These data suggest that Sertoli cells exert a regulatory action on Leydig cell steroidogenic activity via FSH dependent secreted proteins.
Data from several experimental approaches strongly suggest that Sertoli cells exert a paracrine control of the two main testicular functions, androgen secretion and spermatogenesis. Further evidence supporting this role of Sertoli cells was obtained by coculture of Sertoli cells with other testicular cells. Coculture of pig or rat Sertoli cells with pig Leydig cells produces an increase in the hCG receptor number and an increase in the steroidogenic activity of Leydig cells. Pretreatment with FSH further increases the values of these two parameters. These biochemical changes were associated with ultrastructural changes in Leydig cells. The effects of Sertoli cells on Leydig cells depend upon the ratio of the two cells and on the substrate in which the cells are cultured. Moreover, Leydig cells produce an increase in the FSH receptor number and in the FSH stimulation of plasminogen activator production by Sertoli cells. Coculture of rat or pig Sertoli cells with rat germ cells, induces an increase in the RNA and DNA biosynthetic activities of germ cells. Most of the stimulatory effects seemed to be mediated by diffusible factors, secreted by Sertoli cells, but full expression of the stimulatory action was observed when germ cells were in contact with other cells. In this coculture system, a fraction of rat germ cells containing mainly mature forms of spermatocytes inhibited rat Sertoli cell RNA and DNA synthesis, but had no effect on pig Sertoli cells. On the contrary, a fraction of rat germ cells richer in spermatogonias and preleptotene spermatocytes, stimulated rat Sertoli cell DNA synthesis but was without effect on pig Sertoli cells. These results clearly show that the stimulatory effects of Sertoli cells on Leydig and on germ cells which are not species specific are mediated mainly by diffusible factors, the secretion of which is regulates by FSH.
The effects of follicular stimulating hormone (FSH) on testicular steroidogenic activity has been studied by testing the capacity of conditioned medium (CM) by both unstimulated (control) Sertoli cells (C-CM) and FSH stimulated Sertoli cells (FSH-CM) to influence porcine cultured Leydig cell activity. Leydig cells cultured in FSH-CM for 48 hrs, as compared to C-CM, show a significant (P less than 0.05) increase in [125I]-hCG binding (150% +/- 4) and hCG-stimulated testosterone (T) secretion (266% +/- 42). In addition, the stimulating effect of FSH-CM on Leydig cell function as compared to C-CM, is trypsin sensitive, non dialyzable, heat stable, acid resistant and is chromatographed following gel filtration (Sephadex G 100) into two different peaks of activity. These data suggest that FSH regulates Leydig cell function via (at least two types of) Sertoli cell secreted proteins.
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To determine the precise role of Sertoli cells in the stimulating effects of follicle stimulating hormone (FSH) on Leydig cell activity, porcine purified Leydig and Sertoli cells were cultured separately or together in a chemically defined medium in the absence or presence of porcine, FSH 50 ng/ml. Leydig cell activity was evaluated using two parameters: human chorionic gonadotropin (hCG) binding sites; and hCG-stimulated cAMP production and testosterone secretion. First, it was found that FSH increases Leydig cell activity in crude Leydig cell preparations (40-60% of Leydig cells), whereas it exerts no effect on purified Leydig cells (greater than 90% of Leydig cells). Second, FSH stimulates the activity of Leydig cells cocultured with Sertoli cells, whereas it remains without effect on purified Leydig cells cultured alone. This stimulating effect of FSH on Leydig cell activity is dependent on the Sertoli cell number in the coculture. These data 1) show that the stimulating effect of FSH on Leydig cell function is mediated by Sertoli cells and 2) support the concept of local control of Leydig cell function originating from Sertoli cells.
Interactions between Leydig and Sertoli cells, as well as a stimulatory effect of FSH on Leydig cell activity, have been reported in many studies. In order to investigate these interactions, the ultrastructure of immature pig Leydig cells under different culture conditions has been studied. When cultured alone in a chemically defined medium, there is a marked regression of the Leydig cell smooth endoplasmic reticulum and a swelling of the mitochondria. Addition of FSH or hCG does not prevent these phenomena. Co-culturing of Leydig cells with Sertoli cells from the same animal maintains the smooth endoplasmic reticulum at the level seen in vivo and in freshly isolated Leydig cells. The addition of FSH to the co-culture stimulates its development and increases Leydig cell activity, as assessed by an increase in hCG binding sites and an increased steroidogenic response to hCG. These results suggest that Sertoli cells exert a trophic effect on Leydig cells, and that the stimulatory effect of FSH on Leydig cell function is mediated via the Sertoli cells. These results reinforce the concept of a local regulatory control of Leydig cell steroidogenesis.
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In vivo studies indicate that FSH can modulate Leydig cells steroidogenic activity. However, in the testis only Sertoli cells contain specific FSH receptors. In order to clarify the mechanism by which FSH exerts this effect on testicular steroidogenesis, purified Pig Leydig and Sertoli cells were cultured alone or in co-culture. Leydig cell activity has been evaluated by two parameters: 1. hCG-stimulated testosterone secretion. 2. LH/hCG binding sites. FSH does not stimulate these two parameters of purified Leydig cells when cultured alone. On the other hand, when Leydig cells are co-cultured with Sertoli cells, FSH significantly increases these two parameters of Leydig cell function. These results suggest that the effect of FSH on Leydig cells is not direct but mediated by Sertoli cells.
The fine structure of the fibroblastic cells of the normal bovine endometrial caruncle was described. These cells appeared different when compared with the classical fibroblasts encountered throughout the rest of the stromal endometrium. They possess some features similar to those of myofibroblasts reported in various pathological states, to those of epithelioid fibroblasts and to those of cultured fibroblasts. However, they appeared distinct by a few other aspects. We described here the ultrastructure of these particular fibroblastic cells, as they appeared in the caruncle in vivo and under physiological conditions.
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A histopathological and electron microscopic study of the aortic wall of rabbits intoxicated with Solanum malacoxylon was performed. Histological examination showed local loss of the normal waviness of the elastic fibers and calcium deposits. Electron microscopic study of the corresponding areas showed a modified aspect of the smooth muscle cells with loss of some of their differential characteristics, especially their intracytoplasmic fibrils and densifications. The neighbouring elastic fibers showed an electron-dense peripheral band and sometimes a crystal deposit. X-ray microanalysis revealed the presence of a large amount of calcium in these crystals. Collagen fibers played no apparent role in this calcification. These findings support the idea that a local cellular alteration is necessary prior to elastic calcification. Two hypothetical mechanisms are proposed.
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