Biomedical subjects

Robert Kiss

Publications and source records attributed to Robert Kiss.

69 records · Page 4Linked to original sources

PubMed2002

Hypereosinophilic syndrome induced by neonatal immunization against MHC class II alloantigen: critical role of IL-4.

A significant proportion of patients with the hypereosinophilic syndrome suffer from oligoclonal expansion of type 2 helper T lymphocytes (Th2). Herein, we first provide evidence that mice immunized at birth against a single MHC class II alloantigen develop pathological features mimicking this variant of the hypereosinophilic syndrome. Indeed, C57BL / 6 mice injected at birth with (C57BL/ 6 x bm12)F1 spleen cells displayed T lymphocytes producing high levels of IL-5 and IL-13, increased blood eosinophil counts, eosinophilic infiltrates in various tissues, hyperplasia of lymphoid tissues, as well as serum hyperIgE. Moreover, eotaxin mRNA accumulated in the spleen of these animals. IL-4-deficient mice developed neither expansion of Th2 cells nor pathological changes except splenomegaly. Eotaxin mRNA accumulation was also prevented in these animals. We conclude that neonatal exposure to a single MHC class II alloantigen is sufficient to elicit an IL-4-dependent hypereosinophilic syndrome mimicking the lymphocytic variant of this disorder in humans.

Animals↗

PubMed2002

Islet xenograft rejection in absence of CD8+ T cells does not require either interferon-gamma or interleukin-5.

We recently demonstrated that interleukin-5 and eosinophils mediate rejection of skin allografts when CD8+ T cell-dependent and Th1-type CD4+ T cell-dependent pathways are not functional. The purpose of this study was to determine whether a similar mechanism might be operative during rejection of rat islet xenografts in mice. First, we observed that eosinophils indeed infiltrate rejected islet grafts together with CD4+ and CD8+ T cells. CD8+ T cell depletion significantly enhanced graft survival and a further prolongation of islet function was obtained in combination with interferon-gamma neutralization. However, islet rejection characterized by prominent eosinophil and macrophage infiltration still occurred in this setting. Although eosinophil infiltrates were dramatically reduced in interleukin-5 deficient mice, the ability of these animals to reject islet xenografts under CD8+ T cell depletion and interferon-gamma neutralization was similar to that of wild-type mice. We conclude that in absence of CD8+ T cells and interferon-gamma, macrophages, but not eosinophils, mediate rejection of rat-to-mouse islet xenografts.

Animals↗

PubMed2002

Synthesis and cytotoxic evaluation of analogues of the marine pyridoacridine amphimedine.

4-Substituted-7H-pyrido-[4,3,2-de][1,8] or [1,9]-phenanthroline-7-ones and 9-methyl-1,4-diazanaphtacene-3,10-dione, analogues of the marine pyridoacridine amphimedine were synthesised from isoquinoline-5,8-dione. The first compounds were obtained starting from a Diels-Alder reaction whereas the synthesis of the last compound was initiated by a reaction of condensation with 2-aminoacetophenone. The different tetra- and pentacyclic compounds were evaluated for in vitro cytotoxic activities against six distinct human cancer cell lines. All the compounds exhibit cytotoxic activity with IC(50) values (i.e., the drug concentration inhibiting the mean growth value of the six cell lines by 50%)<10(-7)M for two of them.

Acridines↗

PubMed2002

Galectin-1 is overexpressed in nasal polyps under budesonide and inhibits eosinophil migration.

Because of the importance of galectins for various cellular activities, the influence of the glucocorticoid budesonide on the level of expression of galectins-1 and -3 was investigated in human nasal polyposis. Ten nasal polyps obtained from surgical resection were maintained for 24 hours in the presence of various concentrations of budesonide. As quantitatively demonstrated by means of computer-assisted microscopy, 250 ng/ml (the highest dose tested) induced a pronounced increase of galectin-1 expression. This feature was observed in nasal polyps from allergic patients but not in those from nonallergic patients. Since eosinophils represent the main inflammatory cell population in nasal polyps, we investigated the effect of galectin-1 on their migration levels by means of quantitative phase-contrast computer-assisted videomicroscopy. Our results show that galectin-1 (coated on plastic supports) markedly reduced the migration levels of eosinophils in comparison to P-selectin. On the cellular level, marked modifications in the polymerization/depolymerization dynamics of the actin cytoskeleton (as revealed by means of computer-assisted fluorescence microscopy) and, to a much lesser extent, an increase in the adhesiveness of eosinophils to tested substrata were detectable. The present study therefore reveals a new galectin-1-mediated mechanism of action for glucocorticoid-mediated anti-inflammatory effects.

Administration, Topical↗

PubMed2002

Galectin-1 modulates human glioblastoma cell migration into the brain through modifications to the actin cytoskeleton and levels of expression of small GTPases.

We show that high-grade astrocytic tumors with high levels of galectin-1 expression are associated with dismal prognoses. The immunohistochemical analysis of galectin-1 expression of human U87 and U373 glioblastoma xenografts from the brains of nude mice revealed a higher level of galectin-1 expression in invasive areas rather than non-invasive areas of the xenografts. Nude mice intracranially grafted with U87 or U373 cells constitutively expressing low levels of galectin-1 (by stable transfection of an expression vector containing the antisense mRNA of galectin-1) had longer survival periods than those grafted with U87 or U373 cells expressing normal levels of galectin-1. Galectin-1 added to the culture media markedly and specifically increased cell motility levels in human neoplastic astrocytes. These effects are related to marked modifications in the organization of the actin cytoskeleton and the increase in small GTPase RhoA expression. All the data obtained indicate that galectin-1 enhances the migratory capabilities of tumor astrocytes and, therefore, their biological aggressiveness.

Actin Cytoskeleton↗

PubMed2002

S100A6 overexpression within astrocytes associated with impaired axons from both ALS mouse model and human patients.

Astrogliosis is one of the earliest pathological changes observed in neurodegenerative diseases in general and in amyotrophic lateral sclerosis (ALS) in particular. ALS is characterized by selective degeneration of motoneurons. There are 2 forms of the disease: sporadic ALS (SALS), comprising 90%-95% of cases, and familial ALS (FALS), comprising 5%-10% of cases. FALS is an age-dependent autosomal dominant disorder in which mutations in the homodimeric enzyme Cu/ Zn superoxide dismutase 1 (SOD1) is linked to the disease. The animal model for this disease is a transgenic mouse expressing the mutated human SOD1(G93A) gene. Here we show by immunohistochemistry and double immunofluorescence that astrocytes located near impaired axons of motoneurons that were selectively programmed to die overexpressed S100A6, a Ca2+/Zn2+ binding protein able to translocate into the nucleus. Transgenic mice overexpressing the mutated human SOD1 gene and patients suffering from SALS showed this selective astrocytic S100A6 expression. For instance, the pyramidal tract could be macroscopically detected on S100A6-labeled spinal cord and brainstem sections from SALS patients. Transgenic mice overexpressing the non-mutated SOD1 gene did not overexpress S100A6, although glial fibrillary associated protein astrogliosis was seen. Although these results do not give any clue about the beneficial or detrimental role played by S100A6, its induction may be assumed to appropriately serve some function(s).

Adult↗

PubMed2002

Gastrin significantly modifies the migratory abilities of experimental glioma cells.

Malignant astrocytic tumors are characterized by the pronounced and diffuse migration of tumor astrocytes into the brain parenchyma. The present study shows that gastrin is a brain neuropeptide that is able to significantly modulate astrocytic tumor migration at both invasion and motility levels. In the matter of invasion, gastrin severely reduces the in vitro invasive abilities of C6 rat glioma, 9L rat gliosarcoma, and U373 human glioma cells in a collagen matrix. In vitro, gastrin also markedly modifies the motility features in both C6 and U373 cells, at least partly through a decrease in the expression of the RhoA small GTPase, and so brings about some dramatic modifications to the organization in the actin cytoskeleton. The in vitro preincubation of C6 tumor cells with gastrin significantly increases the life spans of rats stereotactically implanted with these cells as compared with the survival periods of rats implanted with gastrin-untreated C6 cells. As suggested by our in vitro experiments, these effects, observed in vivo cannot relate to only the gastrin-induced decrease in tumor astrocyte migratory abilities. Indeed, gastrin also induces immunomodulatory effects, because we observed a marked gastrin-induced recruitment of lymphocytes into C6 gliomas and 9L gliosarcomas. These data all suggest that gastrin can act as an endogenous modulator of glioma progression.

Animals↗

PubMed2002

Changes in galectin-7 and cytokeratin-19 expression during the progression of malignancy in thyroid tumors: diagnostic and biological implications.

Galectin-7 is associated with p53-dependent onset of apoptosis and proliferation control/differentiation in keratinocyte development. It is also up-regulated in chemically induced rat mammary carcinogenesis. Because the levels of expression of galectin-7 have never been investigated in thyroid tumors (in contrast to those of galectin-1 and -3 associated with malignancy), we initiated analysis of the expression of galectin-7 in benign and malignant thyroid lesions together with that of cytokeratin-19 (CK19), a marker already demonstrated to be useful in diagnosing this kind of lesion. The immunohistochemical expression levels were quantitatively determined by means of computer-assisted microscopy on a series of 84 thyroid lesions including 10 multinodular goiters, 32 adenomas, and 42 carcinomas. Our data clearly indicate a marked down-regulation of galectin-7 expression in a large proportion of adenomas (including the normomacrofollicular, microfollicular, and trabecular variants) if compared with carcinomas. In accordance with results of previous studies, a marked up-regulation of CK19 expression was observed in the thyroid carcinomas, and this contrasted in particular with the low CK19 expression observed in the microfollicular adenomas. Of importance for diagnostic implications, the combination of these two markers enabled our series of microfollicular adenomas (characterized by low galectin-7 and CK19 expression) to be efficiently distinguished from the encapsulated follicular variant of papillary thyroid carcinomas (high galectin-7 and CK19 expression).

Adenoma↗

PubMed2002

C-terminal heptapeptide of gastrin inhibits astrocytomas motility by interacting with a new gastrin binding site.

It is well known that the amidated C-terminal part of gastrin is crucial for its interaction with the classical seven transmembrane domain receptors CCK-1 or CCK-2. Nevertheless, over the past 10 years, several groups have characterized new binding sites using peptides related to gastrin (particularly glycine-extended forms of gastrin) on various tumoral and nontumoral cell lines. In the present study, we focused on the human astrocytic tumoral cell line U373. Although it has been described that gastrin was able to inhibit the motility of these cells, we were unable to detect any classical CCK/gastrin receptor. On the other hand, by using the radiolabeled C-terminal heptapeptide of gastrin ((125)I-G-7), we evidenced a new binding site that possessed a pharmacological profile different from the classical CCK/gastrin receptors. This new gastrin binding site seemed to be coupled to G proteins and be implicated in c-Fos transcription gene. Moreover, we showed that G-7 was able to induce a strong inhibition of U373 cell migration, a crucial biological effect when we know that astrocytoma cells' migration in brain parenchyma constitutes a major feature of malignancy in astrocytic tumors.

Amino Acid Sequence↗

PubMed2002

Glucocorticoid-induced differential expression of the sialylated and nonsialylated Lewis(a) epitopes and respective binding sites in human nasal polyps maintained under ex vivo tissue culture conditions.

We characterized the anti-inflammatory effects of budesonide on the expression of adhesion molecules involving Lewis(a) (Le(a)) epitope, its sialylated derivative (sLe(a)), and their respective binding sites in human nasal polyposis. By computer-assisted microscopy, we quantitatively characterized the level of histochemical expression of L- and P-selectins, sialylated and nonsialylated Le(a) epitopes, and their respective binding sites in both surface epithelium and glandular epithelium of human nasal polyps obtained from surgical resection, maintained under ex vivo tissue culture conditions for 24 hours, and treated or not with budesonide. Intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) were chosen as methodological controls, because data already published in the literature clearly indicated budesonide-mediated effects on ICAM-1 and VCAM-1 levels of expression. The present data show that budesonide significantly modified the levels of expression of ICAM-1 and VCAM-1, and to a lesser extent that of P-selectin, in the surface and glandular epithelia. Budesonide markedly decreased the levels of expression of the binding sites for both Le(a) and sLe(a), while those of Le(a) and sLe(a) remained globally unchanged. In conclusion, the present study documents that glucocorticoid-induced effects can encompass receptors for Le(a) epitopes different from E- and P-selectins on epithelial cells of human nasal polyps.

Anti-Inflammatory Agents↗

PubMed2002

Expression of members of the calcium-binding S-100 protein family in a rat model of cerebral basilar artery vasospasm.

OBJECT: The aim of this study was to investigate the role of S-100 proteins in the onset of vasospasm induced by subarachnoid hemorrhage (SAH), which leads to severe neurological morbidity and death. It has recently been argued that modifications in the levels of expression of some intracellular signaling elements controlling the organization of the actin cytoskeleton (including the rho A small guanosine triphosphatase and its related kinases) play significant roles in the induction of smooth-muscle cell contraction, a calcium-dependent process that is pathognomonic of SAH-induced vasospasm at the molecular level. Several members of the calcium-binding S-100 protein family are known to exercise significant control over the organization of the actin cytoskeleton. METHODS: The levels of expression of S-100 proteins in SAH-induced vasospasm have never been investigated. The authors therefore used a double-hemorrhage rat model of SAH-induced vasospasm to determine whether the levels of expression of S-100B, S-100A1, S-100A2, S-100A4, and S-100A6 proteins on immunohistochemical studies were significantly modified in this pathological condition. Quantitative determination of immunohistochemically confirmed expression of S-100 proteins (accomplished with the aid of computer-assisted microscopy) revealed that SAH-induced vasospasm is accompanied by a very significant increase in S-100B, S-100A2, and, to a lesser extent, in S-100A4 and S-100A6 expression, whereas this condition is not accompanied by significant modifications to S-100A1 expression. CONCLUSIONS: Such significant modifications in the levels of expression of different members of the S-100 protein family in SAH-induced vasospasm could relate to the various roles played by this specific class of calcium-binding proteins at the level of actin cytoskeleton organization. These modifications in S-100 protein expression seem relatively specific to SAH-induced vasospasm, because heparin-induced epilepsy-like symptoms were accompanied by dramatically distinct profiles of S-100 protein expression.

Animals↗

PubMed2002

Parasitic load and histopathology of cutaneous lesions, lymph node, spleen, and liver from BALB/c and C57BL/6 mice infected with Leishmania mexicana.

The course of infection, parasitic loads, and histopathology of cutaneous lesions, draining lymph node, spleen, and liver were compared in BALB/c and C57BL/6 mice over a period of 34 weeks after inoculation in footpad with promastigotes of a Leishmania mexicana reference strain. The results show that the primary footpad lesions first present a 12-week phase that develops similarly in both strains of mice. Thereafter, a cutaneous and visceral dissemination of L. mexicana parasites occurs in BALB/c mice; the latter experience an extensive breakdown of the lymphoid organ microarchitecture, whereas C57BL/6 mice succeed in eliminating the parasite infection from the lymph nodes but not from the primary cutaneous lesion, which does not heal. These results highlight marked differences between responses of key anatomical compartments controlling L. mexicana infection in BALB/c and C57BL/6 mice.

Animals↗

PubMed2002

In vitro pharmacological characterizations of the anti-angiogenic and anti-tumor cell migration properties mediated by microtubule-affecting drugs, with special emphasis on the organization of the actin cytoskeleton.

The aim of the present work is to investigate whether microtubule-affecting drugs including vincristine, vinblastine, vindesine and vinorelbine are able to produce an anti-angiogenic effect at non-cytotoxic doses in the same way of taxol. The cytotoxic effects were determined by means of the colorimetric MTT assay, and the anti-angiogenic effects on HUVEC cells growing on Matrigel and forming capillary networks. Sixteen additional drugs (camptothecin, SN38, topothecan, adriamycin, daunomycin, etoposide, bleomycin, melphalan, mitomycin C, TNP-470, cisplatin, carboplatin, 5-fluorouracil, methotrexate, suramin and batimastat) were used as control in order to test the specificity of the microtubule-affecting drug effects. We also investigated by means of videomicroscopy whether microtubule-affecting drugs could produce anti-migratory effects at non-cytotoxic doses on tumor cells. Finally, we used computer-assisted fluorescence microscopy to characterize the influence of microtubule-affecting drugs on the polymerization/depolymerization dynamics of the actin cytoskeleton in tumor cells. Our results show that taxol, vincristine and vindesine behave similarly in their ability to reduce the capillary network formation by HUVEC cells cultured on Matrigel. These anti-angiogenic effects appear at non-cytotoxic concentrations. In contrast, vinblastine and vinorelbine produce apparent anti-angiogenic effects by direct cytotoxicity. Microtubule-affecting agents are also able to significantly reduce the level of migration of tumor cells at non-cytotoxic concentrations, some of these effects may occur via modifications to the actin cytoskeleton organization. Several types of microtubule-affecting agents could be used as anti-angiogenic agents by administering them at non-cytotoxic concentrations, and some microtubule-affecting agents abandoned in pharmacological assays could turn out to be potent anti-migratory drugs acting on tumor cells, though without being too cytotoxic.

Actins↗

PubMed1997

Computer-Assisted Microscope Analysis of Feulgen-Stained Nuclei in Gonadotroph Adenomas and Null-Cell Adenomas of the Pituitary Gland.

The current classification of clinically nonfunctioning pituitary adenomas is based on immunocytochemical and ultrastructural studies. However, a number of cases have less distinctive features that cannot be easily conformed with the prevailing morphologic classifications. The diagnostic information contributed by the determination of the nuclear DNA content (DNA ploidy level) and quantitative chromatic pattern description as opposed to the morphofunctional diagnosis in clinically nonfunctioning adenomas was consequently investigated in a series of 71 pituitary adenomas, including 31 null-cell adenomas, 35 gonadotropin adenomas, and 5 nonfunctioning adenomas that were not examined by electron microscopy. DNA ploidy level (8 variables) and quantitative chromatin pattern description (30 variables) were carried out by means of the computer-assisted microscope analysis of 80-1600 Feulgen-stained nuclei analyzed/case. The diagnostic information contributed by the 38 quantitative variables was determined by multifactorial statistical analysis (i.e., Discriminant Analysis). This computer-assisted classification significantly differentiated nulLcell adenomas from gonadotropin adenomas (p = 0.0025). In addition, it was able to differentiate three major subtypes of nonfunctioning adenomas on the basis of their immunohistochemical profiles. These were the immunonegative adenomas, the follicle-stimulating hormone (FSH)-positive adenomas, and the a-subunit (a) and/or luteiwizing hormone (LH)-positive adenomas (p < 0.0001 to p < 0.001). We thus suggest that the cytometric image analysis of Feulgen-stained nuclei can contribute on the discrimination of subtypes of clinically nonfunctioning pituitary adenomas.

Journal Article↗

PubMedDate not supplied

Digital holographic microscopy for the three-dimensional dynamic analysis of in vitro cancer cell migration.

Cancer cell motility and invasion are critical targets for anticancer therapeutics. Whereas in vitro models could be designed for rapid screening with a view to investigate these targets, careful consideration must be given to the construction of appropriate model systems. Most investigations focus on two-dimensional (2-D) assays despite the fact that increasing evidence suggests that migration across rigid and planar substrates fails to recapitulate in vivo behavior. In contrast, few systems enable three-dimensional (3-D) cell migration to be quantitatively analyzed. We previously developed a digital holographic microscope (DHM) working in transmission with a partially spatial coherence source. This configuration avoids the noise artifacts of laser illumination and makes possible the direct recording of information on the 3-D structure of samples consisting of multiple objects embedded in scattering media, such as cell cultures in matrix gels. The software driving our DHM system is equipped with a time-lapse ability that enables the 3-D trajectories of living cells to be reconstituted and quantitatively analyzed.

Cell Count↗