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Biomedical subjects

A Piccioni

Publications and source records attributed to A Piccioni.

13 recordsLinked to original sources
PubMed1999

Decay of the GRB 990123 optical afterglow: implications for the fireball model

Broad-band (ultraviolet to near-infrared) observations of the intense gamma ray burst GRB 990123 started approximately 8.5 hours after the event and continued until 18 February 1999. When combined with other data, in particular from the Robotic Telescope and Transient Source Experiment (ROTSE) and the Hubble Space Telescope (HST), evidence emerges for a smoothly declining light curve, suggesting some color dependence that could be related to a cooling break passing the ultraviolet-optical band at about 1 day after the high-energy event. The steeper decline rate seen after 1.5 to 2 days may be evidence for a collimated jet pointing toward the observer.

Journal Article↗
PubMed1999

Early intervention for children with cerebral visual impairment: preliminary results.

According to the ophthalmological literature, cerebral visual impairment (CVI) is defined as a temporary or permanent visual loss caused by a disturbance of the posterior visual pathways and/or occipital lobes. The study of CVI is still a new field, and diagnosis is frequently difficult and sometimes may not even be considered. Different studies have taken into account various aetiologies of CVI. Neurological problems are common findings in children with CVI and this population may also show ocular abnormalities. The present study reviews the clinical history of 76 patients who have been examined at the Robert Hollman Foundation, Cannero, Italy, over the past 3 years. Infants and children were studied from birth to 4 years of age from both a neurological and an ophthalmological point of view. Taking the development of the children into account, responses to visual stimulation were analysed in order to compare the behaviours exhibited by the sample with those described in literature.

Age Factors↗
PubMed1998

Photometry and spectroscopy of the GRB 970508 optical counterpart

An optical transient within the error box of the gamma ray burst GRB 970508 was imaged 4 hours after the event. It displayed a strong ultraviolet excess, and reached maximum brightness 2 days later. The optical spectra did not show any emission lines, and no variations on time scales of minutes were observed for 1 hour during the decline phase. According to the fireball and afterglow models, the intensity should rise monotonically before the observed optical maximum, but the data indicate that another physical mechanism may be responsible for the constant phase seen during the first hours after the burst.

Journal Article↗
PubMed1989

Pre-natal (segment II) toxicity study of cinnamic aldehyde in the Sprague-Dawley rat.

Cinnamic aldehyde (CA) was administered by gavage to Sprague-Dawley rats on days 7-17 of pregnancy at doses of 5,25 or 250 mg/kg body weight/day. Significantly lower weight gain of the dams was observed at the two higher dose levels. No significant dose-related increase of abnormalities was observed: the incidence of poor cranial ossification was significantly increased in all treated groups, while reduced ossification of the tympanic bulla was increased at 25 or 250 mg/kg/day. Significant increases of the incidences of dilated pelvis/reduced papilla in the kidney, dilated ureters and greater than or equal to 2 abnormal sternebrae per foetus were detected in the 2-mg/kg group, which had the highest overall prevalence of minor abnormalities. Since significant increases in the incidences of reduced cranial ossification, dilated ureters and renal variants were observed at 5 mg/kg, a dose at which there was no detectable maternal toxicity, it is suggested that the foetus might be slightly more sensitive than the adult to the action of CA.

Acrolein↗
PubMed1989

Predictive value of serum aluminium levels for bone accumulation in haemodialyzed patients.

Uremic patients undergoing long-term dialysis risk accumulating tissue aluminium burdens and developing aluminium-related syndromes, such as dialysis encephalopathy and osteomalacia. A statistical retrospective study on 253 uremic subjects was carried out to verify the predictive value of serum aluminium levels on bone aluminium accumulation. Serum and bone samples collected at the same time were analyzed for aluminium content. Analyses were performed by graphite furnace atomic absorption technique. The results verified bone aluminium concentrations of less than or equal to 60 mg/kg d.w. (dry weight) in 144 patients and greater concentrations in 109 patients. The statistical discriminant analysis showed that serum levels can be predictive in aluminium bone accumulation (lower or greater than 60 mg/kg) with about a 7% margin of error. This value may be further reduced to about 2% if two threshold limits are used (53-81 micrograms/l). The specificity and sensitivity of the test were 89.6% and 83.5%, respectively.

Aluminum↗
PubMed1988

Determination of heavy metals in samples of urban solid wastes by means of the ICP atomic spectrometry technique.

The concentration of elements of environmental significance in the leachate from landfills of urban solid wastes was determined by means of Inductively-Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The suitability of extraction tests which simulate the leaching process were undertaken. Both highly toxic elements (As, Cd, Co, Cr, Pb and V) and elements present at major concentrations (Al, B, Cu, Fe, Mn, Ni and Zn) were quantified at different levels within and under the landfill. Results showed that the extraction test recommended by EPA is acceptable in order to simulate natural leaching compared with the amounts of the elements which are brought into solution after digestion with nitric acid. Furthermore, significant correlations were found in the landfill composition at different levels for element pairs such as Al-Mn, Co-Cr, Co-Cu, Co-Fe, Co-Mn, Co-Zn, Cr-Fe, Cr-Mn, Cu-Fe, Cu-Zn, Fe-Mn, Fe-Zn, Mn-Zn and Pb-Zn.

Humans↗
PubMed1988

The environmental behavior of chemicals in soil: atrazine as an example.

In this work a mathematical model has been developed and used to estimate the soil vertical distribution of Atrazine dispersed in the environment. Water transport, rise due to capillarity, and partition among soil-contained water, air, and organic matter, as well as degradation processes, are considered. As far as the vertical mobility in soil is concerned, the model has been derived from that proposed by P. H. Nichols, A. Walker, and R. J. Baker [1982). Pestic. Sci. 12, 484-494). Such a model has been extended to include a procedure which takes into account the Atrazine mobility due to gravitational water flow. The organic carbon (O.C.) concentration gradient in soil was also considered in the evaluation when assessing partition processes, according to models by P. J. McCall et al. [1983). Residue Rev. 13, 231-241) and D. McKay and S. Paterson [1982). Environ. Sci. Technol. 16, 12, 654). The degradation processes are assumed to be first order, linearly related with O.C. content in soil. The application of this model to two sets of soil data demonstrated that Atrazine requires a long time (2 years or more, depending on soil features) in order to percolate at a depth comparable with those of a groundwater source.

Atrazine↗
PubMed1988

Teratogenicity study of ammonium glycyrrhizinate in the Sprague-Dawley rat.

Ammonium glycyrrhizinate (AG), a commercially used salt of glycyrrhizic acid, was administered in the drinking-water to Sprague-Dawley rats on days 7-17 of pregnancy. The actual intakes were 0, 21.33 +/- 1.22, 238.75 +/- 17.50 and 679.94 +/- 69.87 mg AG/kg body weight/day for groups 0, 1, 2 and 3, respectively. AG caused polydipsia in the dams. Foetuses from the treated litters did not present an increase in external malformations, a decrease in weight or a decrease in the degree of ossification. However, there was a slight but significant increase in embryolethality and in the prevalence of external haemorrhages. Skeletal examination revealed a dose-related increase in minor anomalies, especially in the sternebral variants. Renal ectopy also increased significantly at the highest dose. These results indicate that the possible embryotoxicity of aromatizing compounds should be considered.

Aldosterone↗
PubMed1987

Subchronic oral toxicity of 4-chloro-alpha, alpha, alpha-trifluorotoluene in Sprague-Dawley rats.

The subchronic oral toxicity of 4-chloro-alpha, alpha, alpha-trifluorotoluene (CTT) was assessed in Sprague-Dawley rats. Four groups of six male and six female rats were treated daily for 28 days, by gavage, with doses of 0, 10, 100 and 1000 mg CTT/kg body weight using olive oil as a vehicle. No clinical signs were observed, other than salivation in the high-dose group in the last week. The males of this group showed a significant decrease in body-weight gain without a concurrent decrease in food consumption. In males, there were significant dose-dependent increases in blood cholesterol and triglycerides, suggestive of alterations in lipid metabolism. The females showed only a small dose-related increase in serum lactate dehydrogenase. Specific histological alterations were found in the males given 1000 mg/kg/day, namely hyaline droplet nephrosis, along with a significant increase in relative kidney weight, and an increase in lipid vacuoles in the adrenal cortex. Slight nephrosis was also observed in males given 100 mg/kg. Both male and female rats showed a significant increase in relative liver weight at a dose of 1000 mg CTT/kg. CTT appears to have a low subchronic oral toxicity. Neither pathological nor biochemical alterations were found at 10 mg/kg body weight/day and this can be defined as the no-observable-effect level (NOEL).

Administration, Oral↗
PubMedDate not supplied

[Application of the OWAS method in the study of work postures among quarry manual workers].

BACKGROUND: Previous ergonomic and epidemiologic studies revealed high postural risk (exceeding the N.I.O.S.H. recommended limits) and relevant damage (significant excess of acute and chronic lumbosacral spinal disease) among the labourers in porphyry quarries in the Province of Trento (Italy). METHODS: An analysis of work postures was made with the OWAS (Ovako Working postures Analysing System) method. RESULTS: A high prevalence of work postures that have a harmful effect on the musculoskeletal system was found. Working methods need to be changed as soon as possible. CONCLUSIONS: The use of the OWAS method permits a detailed analysis of working conditions in order to identify and re-design the activities causing ergonomically problematic postures.

Data Interpretation, Statistical↗