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Biomedical subjects

M Belli

Publications and source records attributed to M Belli.

At least 55 records · Page 3Linked to original sources
PubMed1995

[The physiopathological role and prognostic value of the vasoactive intestinal peptide in acute myocardial infarct].

Aim of our study was to investigate the pathophysiological role of vasoactive intestinal peptide (VIP) in the neuroendocrine activation occurring in acute myocardial infarction (AMI). Plasma VIP concentration has been assayed in 30 patients with AMI, 22 males and 8 females, aged 41-82 years, without other important diseases. VIP plasma values, assayed on admission to the Coronary Care Unit, within 4-6 hours after the onset of chest pain, everyday for the first week and on day 14, were significantly higher in survivors and in patients aged < 60 years. VIP plasma concentration was not statistically correlated with CPK and CPK-MB. VIP seems to play a pathophysiological role in the neuroendocrine activation occurring in AMI. Low VIP plasma levels are associated with an unfavorable short-term prognosis. Moreover, it appears that VIP secretion is negatively influenced by aging.

Adult↗
PubMed1994

Influence of DNA conformation on radiation-induced single-strand breaks.

It is usually assumed that sparsely ionizing radiation produces randomly distributed DNA breakages. This seems to be supported by the finding that in some DNA fragments single-strand scissions occur uniformly at all nucleotide sites, regardless of sequence. We performed experiments on two DNA fragments of about 300 bp having different conformation to test whether radiation-induced single-strand breakage is dependent on DNA conformation. Breakage analysis was carried out by denaturing polyacrylamide gel electrophoresis, which allows determination of the broken site at single nucleotide resolution. We found uniform cutting patterns in B-form regions. On the contrary, X- or gamma-irradiation of curved fragments of kinetoplast DNA showed that the distribution of single-strand breaks was not uniform along the fragment, as the cleavage pattern was modulated in phase with the runs of A-T pairs. This modulation likely reflected the reduced accessibility of the sites which on hydroxyl-radical attack give rise to strand breaks. The cleavage pattern was phased with the runs of A-T pairs. Moreover, the overall yield of strand breaks was considerably lower in curved DNA fragments than in those with extended straight regions. The conformation effect found here indicates that the cleavage pattern reflects the fine structural features of DNA.

Base Sequence↗
PubMed1994

DNA double-strand breaks induced by low energy protons in V79 cells.

The initial production of DNA double-strand breaks (dsb) was determined in V79 Chinese hamster cells irradiated with proton beams of 3.24, 1.50 and 0.88 MeV, corresponding to values of unrestricted LET evaluated at the cell midplane of 10.9, 20.0 and 30.5 keV/micron, respectively. X-rays were used for comparison. Dsb were measured with the low speed sedimentation technique in neutral sucrose gradients. The initial yield of dsb rose linearly with the dose and did not significantly depend on the proton LET, in contrast with the results obtained in previous studies for cell inactivation and mutation induction. Also, no significant differences for dsb induction were found between protons and X-rays. Two possible explanations, not necessarily mutually exclusive, are proposed: (1) dsb are not the only lesions involved in cellular effects; and (2) the initial number of dsb is not the only important parameter since a fundamental role is played by the degree of clustering, i.e. the association of dsb with other dsb or other types of damage.

Animals↗
PubMed1993

Ingested soil as a source of 137Cs to ruminants.

Ingestion of soil has been identified as a potentially important source of radionuclides, particularly to grazing ruminants. Soil artificially contaminated with radiocaesium was administered orally each day for 33 days to Bergamasca sheep and the transfer to milk measured. Two soil types were used, with a clay content of 11% and 16%, respectively. Transfer coefficient (fm) values to sheep milk, calculated at the equilibrium (period from 7th to 21st day after soil administration), were 3.72 x 10(-4) days l-1 (S.D. = 7.2 x 10(-5) days l-1) and 6.11 x 10(-4) days l-1 (S.D. = 9.1 x 10(-5) days l-1), respectively for the two soils. These low values indicate that radiocaesium is not removed from the binding sites on the clay minerals in the gut of the sheep.

Animals↗
PubMed1993

Pathologic findings in the retinal pigment epitheliopathy associated with the amyotrophic lateral sclerosis/parkinsonism-dementia complex of Guam.

BACKGROUND: A pigment epitheliopathy that resembles ophthalmomyiasis interna occurs in approximately 10% of a large sample of the Chamorro population of Guam age 39 years or older; the rate is approximately 50% among those who have amyotrophic lateral sclerosis or Parkinsonism-dementia complex (lytico bodig). METHODS: Since publication of an earlier clinical report of affected patients, several of them have died of their neurologic disease, and their eyes were obtained for pathologic study. This is the first pathologic report of the retinal pigment epitheliopathy seen in the setting of amyotrophic lateral sclerosis/Parkinsonism-dementia complex of Guam and is based on examination of 13 eyes from 7 patients. RESULTS/CONCLUSION: Focal areas of attenuation of the retinal pigment epithelium in association with a reduced amount of intracellular pigment correlated with the funduscopic and gross appearance. No larvae were seen, and there was no evidence of inflammation. The pathogenesis of this pigment epitheliopathy remains undetermined.

Amyotrophic Lateral Sclerosis↗
PubMed1993

Inactivation and mutation induction in V79 cells by low energy protons: re-evaluation of the results at the LNL facility.

During the upgrading of the radiobiological facility at the Laboratori Nazionali di Legnaro (LNL) we found that uncorrected values of the proton energy were used in the past. This circumstance prompted us to perform the re-evaluation of the physical parameters for all the proton beams used in our previous radiobiological investigations (Belli et al. 1987) and, subsequently, the re-evaluation of all our previous dose-response curves for inactivation and mutation induction (Belli et al. 1989, 1991). This re-evaluation leads to significant changes in the dose-response curves and in the RBE-LET relationships only at the two lowest energies (highest LET) used. These two points are not reliable for the identification of a peak in RBE-LET relationship for cell inactivation. In spite of that, the extent of the changes is not such as to modify the general conclusion previously drawn, pointing out that there is a LET range where protons are more effective than alpha-particles.

Animals↗
PubMed1993

Vertical transport of radiocesium in surface soils: model implementation and dose-rate computation.

A mathematical model on the Radionuclide Behaviour in Soil for the study of the migration of radionuclides in undisturbed soil profile has been developed. The model has been calibrated using 134Cs and 137Cs concentrations along soil samples gathered in a natural grassland and beech wood, respectively, located in the Friuli-Venezia Giulia region (northeastern part of Italy). In these sampling sites, the external exposure due to 134Cs and 137Cs distribution along the soil profile has been also assessed.

Accidents↗
PubMed1993

[Effects of immunomodulation on antineoplastic radiotherapy. A controlled clinical study].

It is well known that thymic hormones can counteract immunodepression due to radiation therapy, preventing and reducing the severity and the number of myelotoxic and hematologic reactions. We tried to confirm these findings in a controlled multicenter clinical study involving 1,060 patients undergoing radiation therapy (580 treated with thymopentin 50 mg s.c. every other day, after irradiation and for at least 6 cycles of 4 weeks each, and 480 control patients). Highly statistically significant results (to the ANOVA test) were obtained in the protection against radiation-induced leukopenia in the treated group; furthermore, the treated patients had a marked reduction (p = 0.003 chi 2 test) in the early delayed reactions to irradiation, namely in the upper aero-digestive tract. In general, we observed a better, but not statistically significant recovery of the blood parameters, lymphocyte subsets and skin tests in the treated group versus the control group. Both of the treated groups showed the same trend for Karnofsky performance status and body weight. The local and general protection provided by thymopentin against the reactions to irradiation could be advantageously used for the administration of higher doses of radiation therapy.

Adult↗
PubMed1992

Direct comparison between protons and alpha-particles of the same LET: I. Irradiation methods and inactivation of asynchronous V79, HeLa and C3H 10T1/2 cells.

A direct comparison was carried out of the biological effectiveness of protons and alpha-particles of the same linear energy transfer (LET) under identical conditions with a variety of in vitro biological systems. Monolayers of mammalian cells were irradiated with accelerated beams of protons (1.2 and 1.4 MeV) and alpha-particles (30 and 35 MeV) corresponding to LETs of 23 and 20 keV microns-1 for each particle type. For V79-4 cells it was observed that the linear term of the dose-response for cell inactivation by protons was significantly greater than that for alpha-particles of the same LET. For HeLa and HeLa S3 cells, also, the linear term appeared to be greater for protons, but this was not observed with more limited data for C3H 10T1/2 cells. The result for V79 cells is in agreement with the report of Belli et al. (1989) who observed that the biological effectiveness of protons rose sharply between 17 and 30 keV microns-1 in strong contrast to alpha-particles which reached a peak effectiveness at greater than 100 keV microns-1. These results place new constraints on the biologically relevant features of the microscopic structure of radiation tracks, and have implications for the mechanistic and practical comparison between radiations.

Alpha Particles↗
PubMed1992

Direct comparison of biological effectiveness of protons and alpha-particles of the same LET. II. Mutation induction at the HPRT locus in V79 cells.

Mutation induction at the hprt locus has been studied in V79-4 Chinese hamster cells irradiated with mono-energetic protons and alpha-particles with LET of 20.3 and 23 keV microns-1. The mutation frequency increased linearly with the dose for all the four radiation qualities investigated, so that effectiveness for mutation induction could be expressed by the slope of the relevant curve. This effectiveness did not significantly change with the small change in LET of each kind of particle, while sizeable differences were found between particles. Protons were more effective in mutation induction than alpha-particles with the same LET by a factor of about 2. This finding is similar to, although slightly larger than, the factors 1.5-1.8 found for inactivation of the same cells in the same series of experiments.

Alpha Particles↗
PubMed1992

Direct comparison of biological effectiveness of protons and alpha-particles of the same LET. III. Initial yield of DNA double-strand breaks in V79 cells.

The results reported form part of a series of experiments to substantiate and extend the findings by Belli et al. (1989) that protons are more biologically effective at cell killing than alpha-particles of the same LET. The irradiations were carried out using the Variable Energy Cyclotron (VEC) at the Harwell Laboratories. V79-4 Chinese hamster cells were exposed to alpha-particles and protons with LETs of 20 and 23 keV microns-1 in the dose range 40-150 Gy. X-rays were also used for comparison. Two methods were used for measurement of initial DNA double-strand breaks: sedimentation and DNA precipitation assays. The dose-response relationships were found to be well fitted by straight lines in all cases. With the sedimentation assay a slightly lower yield of dsb was found from protons than from alpha-particles of the same LET. The yield from X-rays was not significantly different from either. The precipitation assay showed similar yields of DNA damage from both particle types but significantly higher yields from X-rays. This may reflect a difference in the type of lesions scored by the two methods. Since the initial amount of dsb does not account for the observed differences in cellular response to radiations of different qualities, it is likely that these are related to the nature of the dsb (affecting reparability) or to the occurrence of other types of molecular damage.

Alpha Particles↗
PubMed1991

Mutation induction and RBE-LET relationship of low-energy protons in V79 cells.

The mutation induction at the HGPRT locus has been studied in V79-753B Chinese hamster cells irradiated with proton beams with energies of 3.36, 1.70 and 1.16 MeV, corresponding to average LET values of 10.6, 17.8 and 23.9 keV/microns, respectively. The mutation curve obtained with 200 kV X-rays was used for comparison. The mutation frequency induced by all the proton beams is considerably higher than that induced at the same dose by X-rays and it is linearly related to the dose. Moreover, the proton effectiveness increases with the LET. The RBEs (evaluated as the initial slope ratios) are 5.0 +/- 0.8, 5.4 +/- 0.8 and 7.7 +/- 1.2 for protons with average LETs of 10.6, 17.8 and 23.9 keV/microns, respectively. These values are higher than those reported in the literature for other ions of comparable LET. This finding parallels what we have already found for cell inactivation (for which RBEs of 3.0, 4.6 and 7.3 were obtained at the same LETs), and indicates that for mutation induction, also, the RBE-LET relationship may depend on the type of radiation.

Animals↗
PubMed1991

Relationships between cell killing, mutation induction and DNA damage in X-irradiated V79 cells: the influence of oxygen and DMSO.

The relationships between cell killing, mutation induction and DNA double (dsb) and single (ssb) strand breaks have been studied in V79 cells irradiated with X-rays under oxic and anoxic conditions in the presence and in the absence of dimethylsulphoxide (DMSO). Curvilinear relationships were found between all pairs of endpoints, except for dsb versus ssb. Statistical analysis of experimental data has shown that in the absence of DMSO there is evidence of good correlations between cell killing, mutation induction and dsb in oxic and anoxic conditions. However, when DMSO was present, no significant correlation was found. In the presence of oxygen DMSO always exerts a protective effect while in anoxia it is generally much less protective and induces a strong sensitization with respect to mutation induction. Possibly DMSO acts not only as a radical scavenger but also as an agent inducing chromatin relaxation and/or under anoxia, forming highly mutagenic short-term radicals. The present data suggest that lethal and mutational events are at least partially independent and not proportional to the initial number of DNA breaks. This may imply that either other kinds of lesions are involved in cell lethality and mutability, or dose-dependent repair mechanisms of dsb have to be considered.

Animals↗
PubMed1991

Evaluation of TATI and other markers in solid tumors.

The usefulness of tumor-associated trypsin inhibitor (TATI) in the diagnosis of various solid tumors was compared to other tumor markers occurring in serum and urine (CEA, CA19-9, CA125, CA72-4, CA50, CA15-3, CA72-4, NSE, TPA, AFP, CK-BB and ferritin). TATI was particularly well suited for the diagnosis of tumors of the pancreas, ovary, oesophagus and bladder. For tumors of these organs TATI may be considered the marker of choice. TATI was also a good marker for distinguishing between disease with or without liver metastasis in cancer of the colon and the breast.

Biomarkers, Tumor↗
PubMed1991

[In vitro and in vivo biocompatibility tests of some endodontic cements].

The major goal of endodontic therapy has been achieved by condensing filling materials into the root canal. It is not uncommon to find excess material in the periapical tissue. It therefore becomes obligatory to use filling materials that have acceptable biocompatibility. The purpose of this investigation was to obtain a "toxicity profile" of some root canal materials and to compare our observations to study results found in literature. Gutta-percha and five endodontic filling cements were tested in vivo and in vitro. The in vivo biocompatibility involved the placement of the test material in 10 mm teflon tubes with an outer diameter of 1,3 mm which were then implanted subcutaneously into rats. The implants were left in situ for periods of 30 and 90 days. The hemolysis test was used for in vitro evaluations. The histological examination showed cellular responses of different intensity and extent. In some cases severe infiltration of inflammatory cells and areas with necrostis were observed. As a result, the root canal materials evaluated showed slight, moderate, and severe reactions, therefore, a different pattern in tissue response.

Animals↗
PubMed1990

Etoposide versus etoposide plus high-dose cisplatin in the management of advanced non-small cell lung cancer. Results of a prospective randomized FONICAP trial. Italian Lung Cancer Task Force.

Two hundred sixteen patients with unresectable non-small cell lung carcinoma were randomly allocated to receive etoposide (120 mg/m2, days 1-3) either alone or in combination with high-dose cisplatin (60 mg/m2, days 1-2). The patients' distribution and characteristics were similar in the two treatment arms. The objective response rate for etoposide was 7% versus 25.8% for etoposide plus cisplatin (P less than 0.005). Median progression-free survival in etoposide arm was 3.5 months versus 5 months in the combination arm (P = 0.43). The median survival time for etoposide was 6 months compared with 8 months for etoposide combined with cisplatin (P = 0.87). Significantly more nausea/vomiting (P less than 0.005), serum creatinine elevation (P less than 0.005), hearing loss and/or tinnitus (P less than 0.005), peripheral neuropathy (P less than 0.005), leukopenia (P less than 0.025), and anemia (P less than 0.005) occurred in the etoposide plus cisplatin arm. No statistically significant difference was recorded between the two arms in terms of performance status changes. In conclusion the addition of high-dose cisplatin to single-agent etoposide significantly increases the chance of obtaining tumor response in advanced non-small cell lung cancer at the cost of an increased toxicity without any significant long-term impact on survival and progression-free survival.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Transfer of Chernobyl fall-out caesium radioisotopes in the cow food chain.

From February to October 1987 samples of milk, grass and other components of the cow diet were regularly collected and analyzed for their radiocaesium contents in 26 sampling stations in a north-eastern region of Italy (Friuli-Venezia Giulia). In this paper we report the feed-to-milk transfer factors for radiocaesium obtained in 13 farms of this region of Italy.

Accidents↗