Biomedical subjects

E Pasquali

Publications and source records attributed to E Pasquali.

At least 19 recordsLinked to original sources

PubMed2006

Insulin resistance and low urinary citrate excretion in calcium stone formers.

Epidemiological data suggest an association between kidney stones and some features of metabolic syndrome such as an overweight condition, arterial hypertension or glucose intolerance. However, mechanisms remain to be elucidated. This study aimed to evaluate insulin resistance, as assessed by homeostasis model assessment (HOMA-IR), and urine composition analysis in patients affected by calcium nephrolithiasis. A cohort of 61 (38 male, 29-57 years of age) non-diabetic calcium stone formers was studied. Data about body mass index, arterial blood pressure, serum biochemistry including parathyroid hormone and calcitriol were recorded in all the patients; fasting glucose and insulin were determined to calculate HOMA-IR value and accordingly the patients were grouped into tertiles. Urine pH and urinary excretion of calcium, citrate, phosphate, oxalate, uric acid, urea and creatinine were measured on 24h urine samples. Patients of the highest HOMA-IR tertile showed lower urine citrate levels than patients of the lowest HOMA-IR tertile (475+/-243 vs. 630+/-187 mg/24h, p<0.05), whereas no difference was detected as far as urinary oxalate, calcium, uric acid, phosphate, and urine pH and urine volume output were concerned. HOMA-IR values were positively related to uric acid serum levels (r=0.31, p<0.05) and negatively to urinary citrate excretion (r=-0.26, p<0.05). Hypocitraturic patients showed higher levels of HOMA-IR than normocitraturic ones (3.03+/-0.92 vs. 2.25+/-1.19, p<0.05). This study shows that a higher level of insulin resistance is associated with lower urinary citrate excretion, and that hypocitraturic patients show a greater insulin resistance than normocitraturic calcium stone formers. This may be related to changes in citrate, Na(+)-K(+) and H(+) renal tubule transports, which have been described in insulin resistance. In conclusion, insulin resistance may contribute to an increased risk of calcium stone formation by lowering urinary citrate excretion. This finding suggests the need for a careful metabolic assessment in patients known to form calcium stones in order to ensure stone recurrence prevention and cardiovascular protection.

Adult↗

PubMed2006

Two-hit model for progression of medulloblastoma preneoplasia in Patched heterozygous mice.

Inactivation of one Ptc1 allele predisposes humans and mice to spontaneous medulloblastoma development, and irradiation of newborn Ptc1 heterozygous mice results in dramatic increase of medulloblastoma incidence. While a role for loss of wild-type (wt) Ptc1 (LOH) in radiation-induced medulloblastomas from Ptc1(neo67/+) mice is well established, the importance of this event in spontaneous medulloblastomas is still unclear. Here, we demonstrate that biallelic Ptc1 loss plays a crucial role in spontaneous medulloblastomas, as shown by high rate of wt Ptc1 loss in spontaneous tumors. In addition, remarkable differences in chromosomal events involving the Ptc1 locus in spontaneous and radiation-induced medulloblastomas suggest distinct mechanisms for Ptc1 loss. To assess when, during tumorigenesis, Ptc1 loss occurs, we characterized cerebellar abnormalities that precede tumor appearance in Ptc1(neo67/+) mice. We show that inactivation of only one copy of Ptc1 is sufficient to give rise to abnormal cerebellar proliferations with different degree of altered cell morphology, but lacking potential to progress to neoplasia. Furthermore, we identify biallelic Ptc1 loss as the event causally related to the transition from the preneoplastic stage to full blown medulloblastoma. These results underscore the utility of the Ptc1(neo67/+) mouse model for studies on the mechanisms of medulloblastoma and for development of new therapeutic strategies.

Aging↗

PubMed2000

Three dimensional (3D) analysis of the morphological changes induced by 50 Hz magnetic field exposure on human lymphoblastoid cells (Raji).

Human Raji B lymphoid cells after exposure for 64 h to a 1 mT (rms) 50 Hz sinusoidal magnetic field showed a reorganization of membrane and cytoskeletal components. Atomic force microscopy in air revealed several modifications in 80% of the exposed cells, such as loss of microvilli-like structures followed by progressive appearance of membrane introflections. This change in plasma membrane morphology was also accompanied by a different actin distribution, as detected by phalloidin fluorescence. These observations support our previous hypothesis that electric and magnetic fields may modify the plasma membrane structure.

B-Lymphocytes↗

PubMed1997

Effect of extremely low frequency (ELF) magnetic field exposure on morphological and biophysical properties of human lymphoid cell line (Raji).

Human B lymphoid cells (Raji) were exposed for 72 h to a 50 Hz sinusoidal magnetic field at a density of 2 milliTesla (rms). The results of exposure showed a decrease in membrane fluidity as detected by Laurdan emission spectroscopy and DPH fluorescence polarization. Field exposure also resulted in a reorganization of cytoskeletal components. Scanning electron microscopy (SEM) revealed a loss of microvilli in the exposed cells. This change in plasma membrane morphology was accompanied by a different actin distribution, as detected by phalloidin fluorescence. We also present evidence that EMF exposure of Raji cells can interfere with protein phosphorylation. Our observations confirm the hypothesis that electric and magnetic fields may modify the plasma membrane structure and interfere with the initiation of the signal cascade pathways.

Actins↗

PubMed1997

Cell-cycle kinetics of Friend erythroleukemia cells in a magnetically shielded room and in a low-frequency/low-intensity magnetic field.

This work was undertaken to compare the behavior of Friend erythroleukemia cells in a solenoid, where the magnetic field was 70 microT at 50 Hz (plus 45 microT DC of Earth) with that of the same cells in a magnetically shielded room, where the magnetic field was attenuated to 20 nT DC and 2.5 pT AC. The control laboratory magnetic field corresponded to 45 microT DC and a stray 50 Hz field below 0.2 microT. The culture growth cycle of cells maintained inside the solenoid was slightly accelerated compared with that of cells maintained outside the solenoid (P < .05). This stimulation probably depended on sensitivity of cell cycle to a magnetic field, because, inside the solenoid, the percentage of G1 cells slightly increased during the culture growth cycle, whereas that of S cells slightly decreased. Acceleration of growth was detected soon after exposure of the cultures to the solenoid field, and growth did not change further if the action of this field continued for a long time, accounting for adaptation. The solenoid field also caused a small increase of cell survival without influencing cell volume. By contrast, the culture growth cycle of cells maintained inside the magnetically shielded room was slightly decelerated compared with that of cells maintained outside the room (P < .05). The essential absence of any field inside the magnetically shielded room also caused a small increase of cell volume, whereas, during the culture growth cycle, the percentage of G1 cells decreased, and that of S cells increased. The majority of these events did not change in cells induced to differentiate hemoglobin through dimethylsulfoxide.

Animals↗

PubMed1997

Scanning eye movements made when viewing film: preliminary observations.

Eye movements were recorded in 10 adult subjects during the viewing of fiction and nonfiction films. Individual differences in scan paths for fiction films were found to be relatively small. Generally, eyes concentrated on the screen center when looking at characters and objects in rapid motion. Scan paths through the screen were observed in special cases, for example, in the case of a dialogue between two characters. No differences emerged in scan paths for the same clip presented in black-and-white and color versions. Results are relevant for both filmmaking and research on perceptual and cognitive strategies involved in processing motion pictures.

Adult↗

PubMed1997

Exposure to a 50 Hz electromagnetic field induces activation of the Epstein-Barr virus genome in latently infected human lymphoid cells.

The EBV genome in latently infected lymphoid cells offers an opportunity to follow effects on the transcriptional and translational product clearly distinguishable from those of the host cell genome. Exposure of Akata cells, a human lymphoid cell line latently infected by the EBV genome, to a 50 Hz EMF resulted in an increased number of cells expressing the virus early antigens. This finding provides additional evidence that DNA can be modulated by a magnetic field.

Antigens, Viral↗

PubMed1995

The effect of raw potato starch on energy expenditure and substrate oxidation.

Because resistant starch (RS) is not absorbed as glucose in the small intestine of healthy humans, postprandial thermogenesis should be lower after the intake of RS as compared with digestible starch. To evaluate this hypothesis, we measured 5-h postprandial thermogenesis and substrate oxidation by indirect calorimetry after ingestion of 50 g pregelatinized (0% RS) and 50 g raw potato starch (54% type II RS) in 15 healthy, normal-weight young males. The subjects consumed each starch (mixed in diluted fruit syrup) twice on separate days and in random order. RS intake was followed by lower thermogenesis (46.5 +/- 13.1 compared with 115.4 +/- 10.4 kJ/5 h; P = 0.008), lower glucose oxidation (P < 0.0005), and greater fat oxidation (P = 0.013) than was pregelatinized starch consumption. Our results suggest that RS has no thermogenic effect and that its presence does not influence the size of the thermic response to digestible starch.

Adult↗

PubMed1980

Visual evoked potentials basic references.

A list is given of 60 basic references (monographs and general reviews) in the field of evoked potentials and event-related brain potentials applied to vision research in man.

Bibliographies as Topic↗

PubMed1980

Eyeblink, evoked potentials and visual attention.

Eyeblink signals and evoked potentials were recorded and averaged in humans during the tachistoscopic presentation of gratings at various spatial frequencies and levels of luminance. It was confirmed that at high spatial frequencies and low levels of luminance the latency of evoked potentials increased and their amplitude decreased. At the same time there was a longer inhibition of the eyeblink, which was more precisely timed on the stimulus. This points to the existence of a central system that regulates the eyeblink in accordance with the attention involved in visual information processing.

Adult↗

PubMed1976