Stefania Pacini

Exposure to global system for mobile communication (GSM) cellular phone radiofrequency alters gene expression, proliferation, and morphology of human skin fibroblasts.

Human skin fibroblasts were exposed to global system for mobile communication (GSM) cellular phone radiofrequency for 1 h. GSM exposure induced alterations in cell morphology and increased the expression of mitogenic signal transduction genes (e.g., MAP kinase kinase 3, G2/mitotic-specific cyclin G1), cell growth inhibitors (e.g., transforming growth factor-beta), and genes controlling apoptosis (e.g., bax). A significant increase in DNA synthesis and intracellular mitogenic second messenger formation matched the high expression of MAP kinase family genes. These findings show that these electromagnetic fields have significant biological effects on human skin fibroblasts.

EFFECT OF 0.2 T STATIC MAGNETIC FIELD ON HUMAN NEURONS : REMODELING AND INHIBITION OF SIGNAL TRANSDUCTION WITHOUT GENOME INSTABILITY

We describe the effect of the static magnetic field generated by a 0.2 T magnetic resonance tomograph on a normal human neuronal cell culture (FNC-B4). After 15 min exposure cells showed dramatic changes of morphology: they formed vortexes of cells and exposed branched neurites featuring synaptic buttons. At the same time, thymidine incorporation and inositol lipid signaling were significantly reduced. Control (sham exposed) or non-neuronal cells (mouse leukemia, and human breast carcinoma cells) did not show any alteration following exposure. Endothelin-1 release from FNC-B4 cells was also dramatically reduced after 5 min exposure. However, PCR analysis of 12 DNA microsatellites selected as gauges of genome instability, did not reveal any alteration following exposure, thus ruling out a direct effect of the magnetic field on DNA stability. These data can be interpreted as a specific effect of the static magnetic field on human neuronal cells and are consistent with the induction of remodeling and differentiation; they demonstrate that fields below 0.5 T have significant biological effects on human neurons.

Effects of 0.2 T static magnetic field on human skin fibroblasts

Human skin fibroblasts were exposed to 0.2 T static magnetic field generated by a magnetic resonance tomograph. After 1h exposure, cell morphology was modified in association with a concomitant decrease in the expression of some sugar residues of glycoconjugates. Study of cell proliferation and mitogenic signal transduction showed a decrease of thymidine incorporation and of second messenger formation. However, cell viability, assessed by colony forming assay, was unaffected. These results demonstrate that the static magnetic field generated by routinely used magnetic resonance tomograph induces alterations on human skin fibroblasts.

Association between Vitamin D Receptor Gene Polymorphism and Nephrolithiasis

Aims: To study the distribution of vitamin D receptor (VDR) gene alleles in hypercalciuric and nonhypercalciuric nephrolithiasis patients, hypothesizing that distinct biochemical parameters would be associated with different VDR genotypes. Methods: 12 hypercalciuric, 15 normocalciuric nephrolithiasis patients, and 150 healthy subjects were recruited. The individual genetic pattern for VDR was evaluated by DNA extraction followed by polymerase chain reaction amplification of the VDR gene and digestion with the restriction enzyme BsmI. Results: In the hypercalciuric group, Bb patients represented 50% (6/12); bb patients 33% (4/12), and BB cases were 16% (2/12). The VDR frequency distribution was not statistically different in hypercalciuric patients and controls (Bb 72%; bb 16%; BB 12%). In the nonhypercalciuric group, the prevalence of the bb genotype (7/15; 47%) was thrice the percentage of control subjects, while the percentage of BB patients was similar to that of the control group (2/15; 13%). Patients with the bb haplotype exhibited a higher daily urinary calcium excretion. Among hypercalciuric patients, after a calcium-restricted diet, bb patients showed a 39% reduction in daily urinary calcium excretion in comparison with a nonsignificant 13% reduction observed in BB subjects (p = 0.004). Conclusions: The effects of VDR gene polymorphism on calcium metabolism contribute to the understanding of the pathogenesis of urinary calculi.

Transdermal Delivery of Heparin Using Pulsed Current Iontophoresis

PurposeIn clinical practice heparin has to be administered by injection with obvious disadvantages; thus, transdermal delivery by electrically assisted methods have been studied. In this study we evaluated the efficacy of a Food and Drug Administration-approved pulsed current iontophoresis system in delivering heparin through living rat skin.MethodsFluorescent and radioactive heparin as well as a commercial heparin preparation were delivered through rat skin via a pulsed current iontophoresis system.ResultsPulsed current iontophoresis allowed fluorescent heparin to cross the stratum corneum localizing in epidermis and dermis. Unfractionated, high-, and low molecular weight fraction pools, obtained by fractionating [35S]-unfractionated heparin on a molecular weight sieve, were then separately tested. Pulsed current iontophoresis elicited the transdermal delivery of low molecular weight heparin, but not that of high molecular weight heparin. Finally, pulsed current iontophoresis of an unfractionated pharmaceutical heparin preparation significantly decreased plasmatic factor Xa activity.ConclusionsWe hypothesize that this technique could be used to administer low molecular weight heparin in a cost-efficient and safe manner without the need for syringes and needles.

Cadmium modulates proliferation and differentiation of human neuroblasts

Cadmium is an environmental pollutant inducing numerous pathological effects, including neurological disorders and brain diseases. However, little is known about the molecular mechanisms of cadmium in affecting neurons and in inducing neurotoxicity in the development of the human brain. We have recently established, cloned, and propagated in vitro a primary long‐term cell culture (FNC‐B4) obtained from the human fetal olfactory neuroepithelium. In the present study, we show that different concentrations of cadmium chloride (CdCl2) induced dose‐dependent biological effects in FNC‐B4 cells. A low concentration (10 μM) of CdCl2 stimulated neuroblast growth, whereas a high concentration (100 μM) inhibited the growth and the viability of neuroblasts inducing morphological and cytoskeletal alterations as well as apoptotic cell death. We also observed that CdCl2 affected, in a dose‐dependent manner, the differentiation of FNC‐B4 neuroblasts, with increased mRNA and protein levels of differentiation markers and decreased expression levels of neuronal stem markers. Furthermore, differentiated cells co‐expressed glial and neuronal markers. We suggest that CdCl2 in FNC‐B4 neuroblasts might represent a selective cue by which, in a heterogeneous primary culture, the more differentiated mature cells die, whereas the undifferentiated cells, at the same time glial and neuronal progenitors, are forced to access a state of differentiation.

Mitogenic signal transduction: A common target for oncogenes that induce resistance to ionizing radiations

We hypothesized that resistance to ionizing radiations accompanying neoplastic transformation caused by some oncogenes was due to common biochemical pathways affecting the mechanism of mitogenic signal transduction. In order to verify this hypothesis, we studied the formation of mitogenic second messengers in cells transformed by oncogenes that induce radioresistance. We observed an increase of diacylglycerol which activates protein kinase C, an increase of phosphatidylcholine metabolism, with a concomitant decrease of inositol lipid metabolism. Our data show that sensitivity to ionizing radiations was inversely related to the intracellular level of diacylglycerol; study of signalling alterations in spontaneous tumors could provide predictive indications about the responsiveness of neoplasia to radiation therapy.

Altered metabolism of glutathione in cells transformed by oncogenes which cause resistance to ionizing radiations

We measured glutathione (GSH) metabolism in normal NIH/3T3 fibroblasts, and in cells transformed by the oncogenes sis, erbB, src, ras, dbl, and raf.erbB,src,ras and raf, but not sis and dbltransformants, showed increased level of total and reduced GSH as compared with normal NIH/3T3 fibroblasts; oxidized GSH was elevated only in src‐ and ras‐transformed cells. Increased total GSH content was associated with decreased activity of the synthetic enzyme γ‐glutamylcysteine synthetase, and oxidized GSH level with increased activity of GSH reductase. These data suggest that GSH synthesis was selectively enhanced in cells transformed by specific oncogenes, with resulting down‐regulation of its synthetic enzyme; alterations of GSH metabolism appeared to be peculiar of transformation by specific oncogenes, and not trivial epiphenomena of neoplastic transformation. Oncogenic transformants that presented elevated level of GSH were also those reported to be resistant to antineoplastic drugs and ionizing radiations, thus confirming a possible link between altered GSH metabolism and resistance to antineoplastic treatment.

A Novel Role for a Major Component of the Vitamin D Axis: Vitamin D Binding Protein-Derived Macrophage Activating Factor Induces Human Breast Cancer Cell Apoptosis through Stimulation of Macrophages

The role of vitamin D in maintaining health appears greater than originally thought, and the concept of the vitamin D axis underlines the complexity of the biological events controlled by biologically active vitamin D (1,25(OH)(2)D3), its two binding proteins that are the vitamin D receptor (VDR) and the vitamin D-binding protein-derived macrophage activating factor (GcMAF). In this study we demonstrate that GcMAF stimulates macrophages, which in turn attack human breast cancer cells, induce their apoptosis and eventually phagocytize them. These results are consistent with the observation that macrophages infiltrated implanted tumors in mice after GcMAF injections. In addition, we hypothesize that the last 23 hydrophobic amino acids of VDR, located at the inner part of the plasma membrane, interact with the first 23 hydrophobic amino acids of the GcMAF located at the external part of the plasma membrane. This al1ows 1,25(OH)(2)D3 and oleic acid to become sandwiched between the two vitamin D-binding proteins, thus postulating a novel molecular mode of interaction between GcMAF and VDR. Taken together, these results support and reinforce the hypothesis that GcMAF has multiple biological activities that could be responsible for its anti-cancer effects, possibly through molecular interaction with the VDR that in turn is responsible for a multitude of non-genomic as well as genomic effects.

Iron Indices and Vitamin D Receptor Polymorphisms in Hemodialysis Patients

Cardiovascular disease caused by accelerated atherosclerosis is the major determinant of morbidity and mortality in chronic kidney disease patients. Vitamin D and its analogs provide survival benefit for hemodialysis (HD) patients. Vitamin D exerts its effects through the vitamin D receptor (VDR) that is coded for by a gene showing several polymorphisms that, in turn, are associated with a variety of diseases and differential responses to vitamin D. In this study, we evaluated the association between 4 VDR polymorphisms (ie, those identified by the restriction enzymes BsmI, ApaI, TaqI, and FokI) and iron indices (serum iron, transferrin, transferrin saturation, and ferritin) in 88 hemodialysis patients routinely treated with vitamin D. The absence or presence of the BsmI, ApaI, TaqI, and FokI restriction sites were denominated B and b, A and a, T and t, F and f, respectively. Our results show that in HD patients with transferrin saturation <20%, the F allele was more frequent than in HD patients with transferrin saturation >20% (P = .03). This relationship may provide a link between VDR alleles and iron and nutritional markers, which are highly predictive variables of cardiovascular morbidity and mortality in hemodialysis patients.