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Biomedical subjects

P Vecchia

Publications and source records attributed to P Vecchia.

At least 19 recordsLinked to original sources
PubMed2005

A 700 MHz 1H-NMR study reveals apoptosis-like behavior in human K562 erythroleukemic cells exposed to a 50 Hz sinusoidal magnetic field.

PURPOSE: To study cell damage and possible apoptosis in K562 human erythroleukemic cells exposed for 2 h to an extremely low frequency (ELF) 50 Hz sinusoidal magnetic field with a magnetic induction of either 1 or 5 mT using high resolution proton nuclear magnetic resonance (1H-NMR) spectroscopy. MATERIALS AND METHODS: One-dimensional 1H-NMR spectra were obtained on whole K562 cells and perchloric acid extracts of these cells. In addition, two-dimensional 1H-NMR spectra were also acquired. Cell damage was examined by lactate dehydrogenase release and changes in cell growth were monitored by growth curve analyses, bromodeoxyuridine incorporation and Ki67 antigen localization. Cell death (necrosis and apoptosis) were also studied by using the chromatin dye Hoechst 33258. RESULTS: The variations in numerous metabolites observed with 1H-NMR reveal apoptosis-like behavior in response of K562 cells to ELF fields. CONCLUSION: 1H-NMR can be extremely useful in studying the effects of ELF fields on cells. In particular, the variations in metabolites which suggest apoptosis-like behavior occur when the cells are not identifiable as apoptotic by more traditional techniques.

Apoptosis↗
PubMed2004

Output power levels from mobile phones in different geographical areas; implications for exposure assessment.

BACKGROUND: The power level used by the mobile phone is one of the most important factors determining the intensity of the radiofrequency exposure during a call. Mobile phone calls made in areas where base stations are densely situated (normally urban areas) should theoretically on average use lower output power levels than mobile phone calls made in areas with larger distances between base stations (rural areas). AIMS: To analyse the distribution of power levels from mobile phones in four geographical areas with different population densities. METHODS: The output power for all mobile phone calls managed by the GSM operator Telia Mobile was recorded during one week in four defined areas (rural, small urban, suburban, and city area) in Sweden. The recording included output power for the 900 MHz and the 1800 MHz frequency band. RESULTS: In the rural area, the highest power level was used about 50% of the time, while the lowest power was used only 3% of the time. The corresponding numbers for the city area were approximately 25% and 22%. The output power distribution in all defined urban areas was similar. CONCLUSION: In rural areas where base stations are sparse, the output power level used by mobile phones are on average considerably higher than in more densely populated areas. A quantitative assessment of individual exposure to radiofrequency fields is important for epidemiological studies of possible health effects for many reasons. Degree of urbanisation may be an important parameter to consider in the assessment of radiofrequency exposure from mobile phone use.

Cell Phone↗
PubMed1997

Mortality of plastic-ware workers exposed to radiofrequencies.

The mortality experience of a cohort of Italian plastic-ware workers exposed to radiofrequency (RF)-electromagnetic fields generated by dielectric heat sealers was investigated. Follow-up extended from 1962 to 1992. The standardised mortality ratio (SMR) analysis was restricted to 481 women workers, representing 78% of the total person-years at risk. Mortality from malignant neoplasms was slightly elevated, and increased risks of leukemia and accidents were detected. The all-cancer SMR was higher among women employed in the sealing department, where exposure to RF occurred, than in the whole cohort. This study raises interest in a possible association between exposure to RF radiation and cancer risk. However, the study power was very small, and the possible confounding effects of exposure to solvents and vinyl chloride monomer (VCM) could not be ruled out. The hypothesis of an increased risk of cancer after radiofrequency exposure should be further explored by means of analytical studies characterised by adequate power and more accurate exposure assessment.

Adolescent↗
PubMed1995

Human natural killer cytotoxic activity is not affected by in vitro exposure to 50-Hz sinusoidal magnetic fields.

Epidemiological studies have suggested, but not demonstrated, a role of exposure to 50/60-Hz magnetic fields in increasing cancer risk in man (workers and the general population). A possible target of magnetic fields is the immune system. In particular, it is known that an important defence against cancer is represented by natural killer (NK) cells capable of killing cancer cell targets. To test this hypothesis, human NK cells, stimulated or not with phytohaemagglutinin or interleukin 2, were exposed to 50-Hz sinusoidal magnetic fields before or during the cytotoxicity test, and then mixed with a variety of target cancer cell lines (Daudi, Raji, U937, H14, IGROV, SW626, K562, HL60). The experiments were performed in two laboratories (Rome and Modena) by means of two different exposure systems. The results of both laboratories suggest that 50-Hz sinusoidal magnetic fields with flux densities up to 10 mT do not affect the cytotoxic activity of human NK cells.

Adult↗
PubMed1995

[Laparoscopic cholecystectomy: evaluation of intraoperative complications with respect to 2 different kinds of anesthesia].

Two anaesthetic managements for elective laparoscopic cholecystectomy were compared in 64 patients in order to investigate some perioperative complications: 1) bowel distension during surgery. 2) recovery from anaesthesia. 3) post-surgery incidence of emesis and pain. In addition, the quality of postoperative peristalsis as well as the time of dimissal were recorded. Group I (n = 30) was treated with NLA in N2O-O2 and Group II (n = 34) received propofol plus fentanyl in air-O2. Bowel distension, evaluated by surgeon at 15 min intervals throughout the operation was similar in both the groups as well as postoperative peristalsis recuperation. During the first 12 hours after laparoscopy no differences were found at any times of observation in the incidence or severity of emesis and pain between the two different anaesthesia patients. In subjects which were given propofol the psychomotor recovery was more rapid than after NLA, particularly during the first 6 hours after surgery. The patients were discharged between 36-48 hours following the operation independently from anaesthetic management. It is concluded that both the anaesthetic techniques provide similar intra/postoperative conditions, except the early recovery that is more rapid for the propofol patients. The overall frequency of emesis and pain was rather high in both the groups, suggesting a routine medication with analgesics and antiemetics.

Adult↗
PubMed1995

[Very low frequency electric and magnetic fields and the immune system].

Recent residential and occupational epidemiological studies indicate a statistical association between 50-60 Hz magnetic field exposure and the risk of developing some kinds of tumors. Several experimental researches have been carried out in vitro and in vivo to verify the possibility that some cell functions may be influenced by ELF (Extremely Low Frequencies: 0-300 Hz) electric and magnetic fields. Such researchers are very important to assess if the statistical association indicated by the epidemiological studies is actually due to a cause-effect relationship between ELF electric and magnetic fields and carcinogenesis. In this review we describe the present state of the experimental research, focusing our attention on the effects of ELF fields on the immune system. We also describe some theoretical researches whose aim is to identify possible mechanisms of interaction between ELF fields and biological systems which may provide biological plausibility to the observed effects.

Animals↗
PubMed1994

[Effects of betamethasone on neuromuscular blockade induced by vecuronium in continuous infusion].

The aim of the study was to determine a possible interaction between a corticosteroid (betamethasone) and vecuronium, a nondepolarizing muscle relaxant. The authors studied 20 patients, ASA I-II, aged 20-54, both sexes, scheduled for abdominal surgery. Mechanomyographic and clinical evaluation by single twitch and TOF stimulation of the ulnar nerve at the wrist and measurement of the concomitant abductor pollicis muscle was applied. The onset time of vecuronium after a single bolus dose of 0.08 mg/kg, duration of action to 10% single twitch recovery, duration of continuous infusion of 0.4-0.5 micrograms/kg/min of vecuronium started at 10% single twitch recovery, and the effects of 0.1 mg/kg betamethasone administration 10 min after continuous infusion were evaluated. The recovery rate of vecuronium after stopping infusion at 10% recovery was also evaluated. Corticosteroids may interact with non-depolarizing muscle relaxants both in prejunctional and postjunctional acetylcholine receptors by several mechanisms of action.

Adult↗
PubMed1991

Non-linear dependence of the dielectric properties of chick embryo myoblast membranes exposed to a sinusoidal 50 Hz magnetic field.

Primary chick embryo myoblasts can be a useful tool for studying the developmental events which accompany myoblast differentiation, particularly myoblast membrane fusion. To determine whether the electrical properties and/or fusion in these systems are affected by 50 Hz magnetic fields, chick embryo myoblast cultures were exposed to B-field intensities ranging from 1 to 10 mT. The electrical parameters of the myoblasts, i.e. membrane conductivity, membrane permittivity and the conductivity of the cell interior (cytosol) were determined by the analysis of conductivity dispersion data in the radio frequency range (10 kHz-100 MHz). Preliminary results indicate that the time of fusion (60 h) is not affected by these fields, but that the absolute values of the two membrane electrical parameters are affected. In particular, a B-field intensity-dependent decrease was observed. The maximum effect resulted after a 1 h exposure to a magnetic flux density of about 5 mT. The conductivity of the cytosol remained unchanged. These data seem to indicate that exposure to 50 Hz magnetic fields affects both static and dynamic membrane properties in primary chick embryo myoblasts.

Animals↗
PubMed1991

[Examples of intervention in cases of electromagnetic pollution in research laboratories].

Two examples of technical measures taken to reduce levels of radiofrequency electromagnetic radiation in research laboratories are reported. The first intervention was aimed at avoiding undue exposure of operators. The case is of interest because of the special exposure conditions, which are not as well characterized as in industrial applications, and require ad hoc analyses, measurements, and mitigation actions. As shown by the second example, such actions also allow effective screening of experimental apparatuses, which is of special importance when high sensitivities are required.

Equipment Design↗
PubMed1991

[An experimental device for measuring the characteristics of echographic emissions].

An experimental system for the evaluation of the parameters characterizing the acoustic power emission of echographs is described. The apparatus is based on a commercial device, which has been modified to allow the analysis of different echographic probes, particularly used for diagnosis. The modified instrument is quite versatile in use and is suitable for the examination of virtually any kind of probe.

Equipment Design↗
PubMed1990

Magnetic resonance imaging: calculation of rates of energy absorption by a human-torso model.

The three-dimensional impedance method was used to estimate specific absorption rate (SAR) in a human-torso model during exposure to the time-varying and static magnetic fields used in magnetic resonance imaging (MRI). Analytical data for discrete tissues as well as the entire torso are presented. Generalized equations were derived that enable calculation of whole-torso SAR over a broad range of conditions. In addition, the impedance method can generate data about internal distributions of SAR, which are needed to predict critical organs that might undergo excessive elevations of temperature. Fair to good agreement was found between impedance-method SAR and those predicted by simple phenomenological models.

Electromagnetic Fields↗
PubMed1986

A health examination of railway high-voltage substation workers exposed to ELF electromagnetic fields.

This is a cross-sectional survey on the health conditions of railways workers active in 258 interconnection and conversion substations all over Italy. Measurements performed in both kinds of substations operating at 220 kV have shown that maximum levels of the electric field strength and of the magnetic flux density at 50 Hz are of the order of 5 kV/m and 15 microT, respectively. Three subject groups, differently exposed (1, 10, 20 h/week), and an unexposed control group, for a total number of 627 workers, constitute the population at study. All subjects underwent a general medical examination, laboratory investigations, and a series of selected examinations relative to three systems (nervous, cardiovascular, and haematopoietic) considered at higher risk. No differences have been found between the exposed and the control groups. It is concluded that workers exposed to ELF electromagnetic fields of moderate strength do not show the presence of clear effects on their state of health.

Electromagnetic Fields↗
PubMed1986

Characterization of macrophages elicited by intraperitoneal injection of hyaluronate.

Hyaluronate of 120,000 molecular weight has been injected in the peritoneal cavity of mice to study its effect on migration of inflammatory cells in vivo. After one day a dose-dependent granulocyte migration is observed. Three days later the number of granulocytes is greatly reduced and macrophages form about half of the total cell population. Hyaluronate-elicited macrophages show a decreased 5'-nucleotidase and an increased acid phosphatase activity as compared to resident macrophages. The production of superoxide anion in response to the phorbol ester tetradecanoyl-phorbolacetate, and the phagocytic activity are also enhanced. Macrophages elicited by hyaluronate secrete growth factor(s) for non-lymphoid mesenchymal cells. It is concluded that hyaluronate in vivo stimulates the migration of inflammatory cells, thus causing the recruitment of a population of stimulating macrophages. These effects may explain previous reports on the acceleration of wound healing by hyaluronate.

5'-Nucleotidase↗
PubMed1983

Healing of hyaluronic acid-enriched wounds: histological observations.

The influence of an exogenous supply of Na hyaluronate (HA) on the healing of superficial skin wounds in healthy and alloxan-induced diabetic rats was histologically assessed. Rats were treated by topical application on the wound site of a 2% Na hyaluronate solution. A facilitating effect of the HA-enrichment on wound repair processes (particularly epithelial migration and differentiation) was markedly evident in wounded diabetic rats. This result is discussed in terms of a possible favorable influence of an HA-enriched wound environment on cell migratory processes occurring during wound healing.

Animals↗