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Biomedical subjects

R Kiss

Publications and source records attributed to R Kiss.

At least 271 records · Page 15Linked to original sources

ACTH sensitivity of isolated human pathological adrenocortical cells: variability of responses in aldosterone, corticosterone, deoxycorticosterone and cortisol production.

In vitro aldosterone, deoxycorticosterone, corticosterone and cortisol production of human adrenocortical cells derived from adenomas (Conn's syndrome, Cushing's syndrome), from hyperplastic adrenals (Cushing's syndrome) and from adrenals surrounding aldosteronoma are described. Cells from adenomas causing either Cushing's syndrome or Conn's syndrome harboured the highest basal and ACTH-stimulated corticosteroid production. Adrenocortical cells derived from micronodular hyperplasia causing Cushing's syndrome and cells from cortisol producing adenoma displayed predominantly cortisol and corticosterone secretion both under basal conditions and following stimulation with ACTH. Aldosteronoma cells showed highly variable aldosterone, deoxycorticosterone, corticosterone and cortisol response to ACTH. However, in aldosteronoma cell suspensions, the basal and ACTH-stimulated ratios of aldosterone to cortisol were increased when compared to ratios of steroids produced by cells from other adrenal tissues. Chronic treatment with spironolactone of patients with Conn's syndrome before surgery was associated with a decreased ratio of aldosterone to corticosterone, revealing that 18-hydroxylase in aldosteronoma cells may be inhibited during long-term therapy. Non-tumorous cells isolated from adrenals surrounding aldosteronoma displayed less aldosterone prior to and after stimulation with ACTH than aldosteronoma cells.

Adenoma↗

Met-enkephalin inhibits mineralocorticoid production in isolated human aldosteronoma cells.

In vitro application of the morphinomimetic met-enkephalin resulted in inhibition of mineralocorticoid production by aldosterone-producing adenomas. Aldosterone, deoxycorticosterone, and corticosterone production by adrenocortical cells isolated from aldosteronomas has been studied under basal conditions and after stimulation with ACTH-(1-24). The blocking effect of met-enkephalin on the rate of aldosterone, deoxycorticosterone, and corticosterone release was significant at a concentration as low as 10(-11) M (P less than 0.001, P less than 0.01, and P less than 0.001, respectively). Dose-dependent inhibition of steroid biosynthesis became more apparent with increasing amounts of met-enkephalin in the incubation medium (10(-11)-10(-5) M); at a concentration of 10(-5) M, met-enkephalin decreased the production of aldosterone by 45%, that of deoxycorticosterone by 51%, and that of corticosterone by 44%. Increased steroid biosynthesis stimulated by ACTH-(1-24) was also significantly blocked by met-enkephalin. In a concentration of 10(-5) M, met-enkephalin produced significant decreases in aldosterone (P less than 0.001), deoxycorticosterone (P less than 0.05), and corticosterone (P less than 0.001) production compared to the peak values obtained after stimulation with 0.85 X 10(-10) M ACTH-(1-24). These data allow us to conclude that the inhibitory effect of met-enkephalin on mineralocorticoid production exerted at the level of the adrenals might be complementary to the factor(s) thought to be involved in the regulation of adrenal steroid production, playing a role similar to that of the biogenic amines originating in the adrenal medulla and regulating the adrenal cortex by a peripheral neurohumoral paracrine mechanism.

Adenoma↗

[Structure of adrenal glands removed for hyperandrogenism and their hormone production in tissue culture].

Authors studied the surgically removed adrenals of a 16 year old girl with hyperandrogenism in tissue culture. The majority of cells in the initial culture was similar to the cells of the normal human adrenal. In the 6 weeks tissue culture the morphology of the cells has shown an alteration. The majority of them contained a small number of lipid droplets, abundant quantity of lysosomes and autophage vacuole. At this period in the media the progesterone level appeared to be elevated. Two months later in the tissue culture numerous transformed cells could be seen and the progesterone level of the media was low. It is believed that alteration of the biosynthesis of progesterone may have a role in the increased production of testosterone and in virilization.

Adolescent↗

Corticosteroidogenesis by isolated human adrenal cells: effect of serotonin and serotonin antagonists.

The direct effect of serotonin and antiserotonin agents on adrenal steroid biosynthesis was studied in isolated adrenal cells derived from patients with Cushing's syndrome. The results indicate that serotonin increases corticosterone production, while the serotonin antagonists cyproheptadine and methysergide depress adrenal steroid - particularly cortisol and aldosterone - biosynthesis.

Adrenal Cortex↗

[Quantitative morphological studies on the zona glomerulosa of the rat adrenal gland. II. Effect of potassium and heparin on the zona glomerulosa].

Authors studied the effect of potassium and heparin on the zona glomerulosa of rats by stereological methods. As the effect of potassium tolerance test the weight of the adrenals, the wideness and volume of the zona glomerulosa, the number and the volume of the cells of it, further the volume of the mitochondria and nuclei in each cell have shown significant increase. After treatment with heparin the wideness of the zona glomerulosa and the volume of the mitochondria appeared to be decreased. Results are in accordance with the aldosterone-level-increasing effect of potassium and with the antialdosteron effect of the heparin.

Adrenal Glands↗

Electron microscopic investigation on the zona glomerulosa of rats after treatment with heparin and potassium.

Adrenal zona glomerulosa of rats was investigated by means of electron microscopy after stimulation with potassium and suppression with heparin. Both intreated and control animals two types of mitochondria -- one with tubular and the other with tubulosaccular cristae -- were found. Stimulation with potassium increased the amount of mitochondria with tubular cristae, heparin treatment caused a simplification of the structure of tubulosaccular cristae. It was assumed that these two mitochondrium-poulations contain different enzyme systems, which catalyze the different step-series of aldosterone biosynthesis. On the basis of cytoplasmic density, dark and light cells could be distinguished only in the zona glomerulosa of control rats, they were absent in both groups of treated animals. The density of these cells probably did not depend on their metabolic activity, but rather on their hormone storage.

Adrenal Cortex↗

Characterization of TNP-470-induced modifications to cell functions in HUVEC and cancer cells.

The aim of the present work is to characterize (both in vitro and in vivo) the influence of TNP-470 on different cell functions involved in angiogenesis and, more particularly, on endothelial cell growth, cell migration and vessel formation. In addition, a possible direct anti-tumor activity was investigated. To this end, we made use in vitro of human umbilical cord endothelial vein (HUVEC) cells and two human cancer cell lines. The TNP-470 effects on the growth of cancer cell lines were compared to those of Taxol (an inhibitor of microtubule depolymerization), a cytotoxic reference which also displays strong antiogenic activity at low (non-toxic) doses. The in vitro effects were characterized on the mouse mammary MXT adenocarcinoma, on which we also characterized the influence of three clinically active anti-tumor compounds (as cytotoxic references). The purpose of this part of the study was to determine the actual TNP-470-related anti-tumor activity and to evaluate the possible toxic side-effects at the doses at which this compound induces tumor growth inhibition. These investigations were completed by analyzing the TNP-470 effects on HUVEC cell motility and in vitro and in vivo vessel formation. The results show that in vitro, TNP-470 inhibited the growth not only of HUVEC, but also of neoplastic cells. Furthermore, TNP-470 clearly inhibited in vitro endothelial cell motility (p<10(-5)). However, it had only a minor effect (p=0.02) on the formation of HUVEC cell networks on Matrigel(R). In vivo, TNP-470 was able to inhibit tumor growth (on the MXT model) at a dose (50 mg/kg) associated with toxic side-effects. Histological examination showed a significant inhibition of vessel formation (p<0.001) at high (toxic) and intermediary (non-toxic) doses (50 and 20 mg/kg). However, we also observed that TNP-470 stimulated lymphocyte proliferation. Thus, care must be taken with the TNP-470 compound in combination with other anti-tumoral agents in order to avoid certain unfortunate clinical complications.

Adenocarcinoma↗

Development and qualification of a novel virus removal filter for cell culture applications.

Commercial bioreactors employing mammalian cell cultures to express biological or pharmaceutical products can become contaminated with adventitious viruses. The high expense of such a contamination can be reduced by passing all gases and fluids feeding the bioreactor through virus inactivation or removal steps, which act as viral barriers around the bioreactor. A novel virus barrier filter has been developed for removing viruses from serum-free cell culture media. This filter removes the 20 nm minute virus of mice by >3 log reduction value (LRV), the 28 nm bacteriophage PhiX174 by >4.5 LRV, the mycoplasma Acholeplasma laidlawii by > or =8.8 LRV, and the bacteria Brevundimonas diminuta by > or =9.2 LRV. Robust removal occurs primarily by size exclusion as demonstrated over a wide range of feedstocks and operating conditions. The filtered media are indistinguishable from unfiltered media in growth of cells to high densities, maintenance of cell viability, and productivity in expressing protein product. Insulin and transferrin show high passage through the filter. The virus barrier filter can be autoclaved. The relatively high membrane permeability enables the use of a moderate filtration area.

Acholeplasma laidlawii↗

Leptin inhibits cortisol and corticosterone secretion in pathologic human adrenocortical cells.

Regulation of adrenal corticosteroid secretion by leptin may involve interactions at multiple levels of the hypothalamic-pituitary-adrenal axis. To investigate the possible direct effects of leptin on corticosteroid secretion of human adrenocortical adenomas, cells from adrenocortical adenomas causing primary aldosteronism (n = 1) and Cushing's syndrome (n = 1), as well as cells from nonhyperfunctioning adrenocortical adenomas (n = 5) were isolated and incubated for 2 h with human recombinant leptin (1-1000 ng/ml) in the presence and absence of adrenocorticotrop hormone (ACTH), then cortisol, corticosterone and aldosterone concentrations in incubating media were determined using radioimmunoassays. It was found that leptin effectively and dose-dependently inhibited basal and ACTH-stimulated cortisol and corticosterone secretion in the three types of human adrenocortical adenoma cells. The inhibiting effect of basal corticosterone secretion was detectable in the presence of leptin concentration as low as 1 ng/ml, with decreases of corticosterone secretion to 34+/-4%, 57+/-11% and 79+/-9% in Cushing's syndrome, primary aldosteronism, and nonhyperfunctioning adrenocortical adenoma cells, respectively. The inhibition of basal cortisol secretion in the presence of low concentration of leptin was less prominent, but 10 ng/ml leptin significantly diminished basal cortisol secretion to 81+/-9% in adrenocortical adenoma cells from Cushing's syndrome, to 68+/-6% in adenoma cells from primary aldosteronism, and to 83+/-8% in cells from nonhyperfunctioning adenomas. The inhibition of ACTH-stimulated cortisol and corticosterone secretion by leptin was similar to those found in cells without ACTH stimulation. By contrast, leptin even at 1000 ng/ml concentration exerted no clear effect on basal and ACTH-stimulated aldosterone secretion in cells from primary aldosteronism and in those nonhyperfunctioning adenoma cells in which aldosterone secretion was detectable. These results indicate that leptin is a potent inhibitor of cortisol and corticosterone secretion in human adenomatous adrenocortical cells. The inhibition of these corticosteroids by leptin may represent a potentially important interaction that exists between leptin and the hypothalamic-pituitary-adrenal axis.

Adenoma↗

Characterization of the hormone-sensitivity of three human non-small-cell lung cancers grafted onto nude mice.

The in vivo hormone sensitivity of three human NSCLCs grafted onto female nude mice (labelled KLX7, KLX9 and KLX14) was characterized on a dynamic level, i.e. on the level of both the macroscopic growth and the proliferative fraction (PF = percentage of cells in the S+G2+M Fractions). Two sets of experiments were performed. The first set showed the influence on the macroscopic growth of the NSCLC xenograft of castration performed either before or after tumor grafting. The second set showed the influence of a pulse of 6 different hormones or growth factors on the PF index magnitude recorded 36 h after their administration to the xenograft-bearing mice. These 6 hormones or growth factors were EGF, estradiol-17-beta (E2), gastrin (G), platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF) and bombesin (B). The results show that the KLX7 model grew definitely faster on the nude mice than the other two models. Ovariectomy before or after tumor grafting did not significantly modify the growth pattern of the KLX7 model, while castration before tumor grafting significantly increased the macroscopic growth of both the KLX9 and the KLX14 tumors. In contrast, E2, bFGF, G and B significantly increased the proliferative activity of the KLX7 model 36 h after their administration to the tumor-bearing mice while remaining without any apparent statistically significant effects in both the KLX9 and the KLX14 models.

Animals↗

Characterization of biological features and chemosensitivity of a new experimental lung metastasis model originating from the MXT mouse mammary adenocarcinoma.

The present study shows how an original mouse metastatic lung model was established from the MXT mammary adenocarcinoma. This metastatic model was obtained by injecting the C/MET clone into the tail veins of B6D2F1 mice. The C/MET clone corresponds to one of eleven cell clones that were isolated in vitro from the MXT model. Of these 11 clones, only the C/MET leads to lung metastatic tumor development when injected i.v. into mice. Furthermore, the C/MET clone colonizes the lung only. The present data show that the C/MET metastatic model and the MXT parental line are weakly (if reference is made to the P388 leukemia model) sensitive to adriamycin, clyclophosphamide and etoposide. However, under specific experimental conditions, the chemosensitivity of the C/MET model can be significantly increased. The C/MET model therefore appears to be an interesting pharmacological tool to test new investigational agents with anti-tumor potentialities to lung metastases.

Adenocarcinoma↗

Sialic acid residues in the labial salivary glands from Sjögren's syndrome patients.

OBJECTIVE: To investigate the composition and expression of sialic acid in the labial salivary glands (LSG) in Sjögren's syndrome (SS). METHODS: LSG of 19 patients with primary SS (n = 11) or secondary SS (n = 8) were studied. Specimens from 7 healthy women served as controls. Computer-assisted microscopy was employed to quantitatively determine the percentage of positive structures, the staining intensity and the heterogeneity for the 4 biotinylated plant lectins Tritricum vulgaris L. (WGA), Maackia amurensis (MAA), Sambucus nigra (SNA) and Canavalia ensiformis L. (Con A). RESULTS: In the acini there was a significant decrease in the staining heterogeneity of WGA in SS compared to controls; the same was observed with respect to MAA staining in the connective tissue and extralobular ducts. In the intralobular ducts, primary SS differed from normal and secondary SS mainly in terms of a decrease in the percentage of positively labeled MAA tissue. In addition, Con A stained acinar cells were significantly more numerous in secondary SS compared with primary SS. CONCLUSION: Differences in the degree of glycoconjugate sialylation were found in SS labial salivary glands, and may play a role in the disease process.

Diagnosis, Differential↗

Characterization of nuclear size, ploidy, DNA histogram type and proliferation index in 79 nerve sheath tumors.

The distribution values of ploidy, of the DNA histogram type, of the proliferation index and of the nuclear area are described in a series of 79 nerve sheath tumors including 7 traumatic neuromas, 55 primary and 9 recurrent benign schwannomas, 5 benign neurofibromas and 3 malignant tumors. The nuclear parameters were computed on Feulgen-stained nuclei (from archival formalin-fixed paraffin-embedded materials) by means of digital cell image analysis. The results show that 20-30% of benign nerve sheath tumors exhibit an abnormal nuclear DNA content (DNA index > 1.30). Such a feature was observed in the four groups of benign tumors, i.e. primary and recurrent schwannomas, neurofibromas and even traumatic neuromas. Aneuploid tumors exhibited triploid, hypertriploid or polymorphic DNA histogram types. The three malignant tumors under study were aneuploid. Lastly, the nuclear area and proliferation index measurements did not allow any clear distinction to be made between the four groups of benign tumors on the one hand, and between the benign and malignant tumors on the other.

Adult↗

[Long-term prognostic value of positive peritoneal washing in colon cancer].

UNLABELLED: We examined the prognostic value of free malignant cells in the peritoneal cavity of patients with colon adenocarcinoma. In 1996-1999, 88 patients underwent peritoneal washing with cytologic analysis immediately before elective colon resection for adenocarcinoma with no evidence of peritoneal metastases. Peritoneal washing fluid was collected before abdominal exploration centrifuged immediately and stained with the May-Grünwald-Giemsa and Harris-Shorr methods. Malignancy was defined as recommended by Papanicolaou. Free malignant cells in peritoneal fluid were found in 25 of 88 (28%) patients (Dukes A 0, of 11, Dukes B 10 of 31, Dukes C 11 of 37, Dukes D 4 of 9). The positive rate was 24 of 75 (32%) among patients with tumors involving the serous layer and 1 of 13 (8%) among the others (p = 0.00989). Positive peritoneal washing was not significantly associated with survival in multivariate analysis. CONCLUSION: The presence of free malignant cells in the peritoneal cavity of patients with colon cancer provided no further prognostic information relative to the Dukes classification in this study. The 5 years survival rates were 48% among patients with positive and negative peritoneal washing respectively (p = 0.09).

Adenocarcinoma↗