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Biomedical subjects

L Alessio

Publications and source records attributed to L Alessio.

At least 19 recordsLinked to original sources
PubMed1992

Reference values for the study of low doses.

At present, the quantitative differences between environmental exposure and occupational exposure to toxic metals are steadily decreasing, it becomes important to establish reference values of the tests used for biological monitoring. However, the word 'reference values' is often used inappropriately and in particular its significance is often confused with that of 'limit values' or 'normal values'. The term reference values defines the levels of the biological indicators in the general population which are not occupationally exposed. It is necessary to refer to these values in order to compare the data obtained through biological monitoring programmes in workers and in groups of the general population which are presumed to be exposed. The most essential aspects for identifying reference values for toxic metals, using a rigorous methodology, are taken into consideration and in particular, the requisites needed for identifying the subjects which must be included in the reference groups are also examined. The modalities for using reference values for individual subjects as well as for groups are then discussed and the main points of research which must be faced in the near future regarding reference values are highlighted.

Environmental Monitoring↗
PubMed1992

Ten-year follow-up of biological monitoring of cadmium-exposed workers.

In this study, 105 workers exposed to cadmium for over 10 years were subjected periodically to environmental monitoring, biological monitoring and medical surveillance. They were divided into subgroups, one in which Cd-B and Cd-U exceeded 10 micrograms/l and 10 micrograms/g creatinine respectively and the other in which they were below these proposed biological exposure indices. Urinary beta 2-microglobulin was used as an indicator of tubular damage. Over the past 3 years 12 workers had raised urinary beta 2-microglobulin values (above 250 micrograms/l). Among workers with Cd-B and Cd-U levels always below the above limits, less than 3% had increased urinary excretion of beta 2-microglobulin, a percentage comparable with that of the reference population. When Cd-B exceeds 10 micrograms/l and Cd-U 10 micrograms/g creatinine on one or more occasions (although the median value still remains below this level), the frequency of tubular damage seems to be considerably higher (8.4 and 7.5% respectively). Thus the Cd-B and Cd-U limits proposed appear to be quite safe if strictly respected. However, median values appear too high to rule out the possibility of an increased incidence of tubular alterations.

Adult↗
PubMed1992

Occupational exposure to cadmium and lung function.

A total of 69 male subjects occupationally exposed to cadmium fumes in a factory producing silver-cadmium-copper alloys for brazing, were subjected to lung function tests, including ventilation (FVC and FEV1), residual volume (RV) and alveolar-capillary diffusion capacity (TLCO and KCO). For each subject, the cumulative exposure to cadmium was calculated as the product of the number of years in the job and the average atmospheric concentration of cadmium (expressed in micrograms/m3) encountered each year. Cadmium-exposed subjects had moderately higher mean values of RV (+ 8%) as compared with the control group; the increase was greater (+ 10%) in the subgroup of workers with greater cumulative exposure to cadmium. No significant differences were observed in FVC, FEV1, TLCO and KCO.

Adult↗
PubMed1992

Definition of reference values for Cd-B and Cd-U: methodological aspects and preliminary results.

In the present study, a definition of the reference values of blood cadmium (Cd-B) and urinary cadmium (Cd-U) was attempted, adopting the same methodology as that used for Hg-B by ICOH and IUPAC. Papers published from 1976 onwards were reviewed. The majority of the studies were concerned with the formation of control groups for toxicological and epidemiological investigations rather than with the definition of reference values. Since the number of subjects for whom data on cadmium were available was small, only the data on Cd-B were considered. After evaluation, only four studies were found to be suitable for the establishment of tentative reference values for Cd-B. It is essential in all such studies to check the statistical and analytical methods for correctness, and the case-list must be selected taking smoking into account as the main interfering factor. It was found that Cd-B values show less dispersion when geometric means and standard geometric deviations are used instead of arithmetic means and standard deviations.

Cadmium↗
PubMed1992

[Evaluation of the effects of reduced glutathione in subjects with acquired and congenital changes in heme biosynthesis].

In order to evaluate the possible therapeutical effects of reduced glutathione in subjects affected by acquired or congenital heme biosynthesis alterations, two groups of subjects have been considered: the first, of 5 subjects with abnormal lead absorption, the second of 10 patients suffering from porphyria cutanea tarda (PCT). The drug was administered i.v. at the dosage of 600-1200 mg for a variable period of 3-5 days in the first group, for 7-10 days in the patients with PCT. In the lead-exposed subjects an increase in the activity of ALA-dehydratases enzyme was observed, with a decrease in the urinary excretion of delta-aminolevulinic acid, and a decrease in the percentage of urinary coproporphyrins as well. In the patients with PCT, after the therapy, a relevant reduction of urinary excretion of porphyrins, prevalently uro- and heptaporphyrins, was noticed. The results of this preliminary study suggest that glutathione can exert an effect of "normalization" on heme biosynthesis when altered in acquired and/or congenital conditions.

Aminolevulinic Acid↗
PubMed1991

Evaluation of beta-endorphin/beta-lipotropin immunoreactivity content in the CSF of patients affected by deafferentation pain syndromes.

Beta-endorphin/beta-lipotropin immunoreactivity (BE/BLPH-IR) content was evaluated in the CSF of patients suffering by deafferentation pain syndromes. BE/BLPH-IR CSF concentrations of these patients were compared with those obtained in a group of patients affected by low back pain and in a control group without pain problems. No statistically significant variation in BE/BLPH-IR levels were found between controls and subjects with different types of chronic pain.

Adult↗
PubMed1991

Primary intrasellar coccidioidomycosis simulating a pituitary adenoma.

The case of a 68-year-old woman who had relatively acute, unilateral ophthalmoplegia is reported. Radiological studies indicated a mass lesion involving the pituitary gland and left cavernous sinus. Pathological tissue obtained by the transsphenoidal approach revealed the presence of a Coccidioides granuloma. This pathological entity should be considered when evaluating patients with a pituitary mass and ophthalmoplegia.

Adenoma↗
PubMed1990

Significance and validity of a shortened lead chelation test.

We evaluated the chelation test in 38 subjects exposed to lead or with suspected lead exposure, comparing the values of lead excretion at the 3rd h (PbU EDTA/3-h) and at the 24th h (PbU EDTA/24-h) after EDTA administration. Good correlation exists between PbU EDTA/3-h and PbU EDTA/24-h (r = .86) and between them and the main biological indicators of dose and effect of lead. When a second chelation test was performed in 15 subjects, a slightly better r coefficient (.93) was observed between the two tests, without reaching statistical significance. It seems difficult, in terms of the type of exposure that we considered, to use the 3-h test, on an individual basis, to predict the PbU EDTA/24-h values.

Adult↗
PubMed1990

[Assessment of exposure to polycyclic aromatic hydrocarbons in 3 work activities using mineral oils].

The exposure to polycyclic aromatic hydrocarbons (PAH) in different industries using cutting, hardening and extruding oils, was investigated determining their concentration in oils and in environmental samples. The following compounds: phenanthrene, anthracene, fluoranthene, pyrene, benzo-a-anthracene, chrysene, triphenylene, benzo-a-pyrene, benzo-e-pyrene and perylene were evaluated by means of gas-chromatography-mass spectrometry. PAH concentrations in oils ranged from 652 to 4461 ng/gr and environmental concentrations from 63.86 to 120.54 ng/mc. In particular the BaP concentrations varied from 0.73 to 1.9 ng/mc. These results, compared with those measured in other environmental surveys and with the limit values proposed in various countries, point out the existence of a very low inhalatory risk of PAH.

Air Pollutants, Occupational↗
PubMed1976

Ultrastructural changes in human leukemic cell nuclei.

The ultrastructural changes of human leukemic cell nuclei have been investigated. Particular attention is paid to the alteration of the nuclear envelope and its constituents, i.e., the pores and the Zonula Nucleum Limitans which appear constantly involved in these pathologic processes. An alteration of the relationship between the components of the nuclear envelope and the chromatin itself may be responsible for the appearance of the most nuclear changes.

Cell Nucleus↗
PubMedDate not supplied

[Lead in the 90's: "new" rules for the "oldest" of environmental toxins?].

Present lead (Pb) exposures in working and general environments are undoubtedly lower than several decades ago so that mean blood lead levels (PbB) in the main industrial sectors using lead, such as ceramics and accumulator manufacturing, are now about 30 micrograms/100 ml and in the general population between 10 and 15 micrograms/100 ml and in some situations decidedly below 10 micrograms/100 ml. At the same time increasingly more accurate and sometimes original knowledge has been acquired on the effects of low-level Pb exposure, especially the effects on the nervous system, the cardiovascular system, the endocrine and immune systems, on heme-containing enzymes, and on the reproductive system. The question of a possible mutagenic and carcinogenic action of Pb is, however, still open. It is also clear that many of the above effects were observed for PbB levels considerably below the current limit levels. For certain effects, like those on heme, the central nervous system, and blood pressure, it has not been possible to establish a threshold below which they will not occur. With effects that are so different in nature and degree and with changed exposure conditions, a critical re-examination of the assumptions on which current knowledge and prevention models are based appeared appropriate. In particular, action models are proposed for discussion which, besides the priority aim of restricting use of Pb to those situations where there is no alternative and to those working environments which guarantee compliance with modern regulations and prevention procedures, have two differentiated objectives: the first is to eliminate the dose-dependent effects occurring at exposures higher than those in the general population; the second is to reduce to the lowest possible level the effects with no threshold or with as yet unestablished threshold, by means of actions in favour not only of occupationally exposed groups but also the general population.

Air Pollutants, Occupational↗
PubMedDate not supplied

[Biological monitoring of occupational exposure to aluminum].

The meaning and usefulness of biological indicators in the study of occupational exposure to aluminium (Al) was assessed on the basis of the most recently acquired knowledge on the toxicokinetics of aluminium absorbed by inhalation, results of environmental and biological investigations recently carried out in industrial sectors with low risk of aluminium absorption (refining, casting and pressure moulding covering a total of 8 plants and 119 workers) and the results of investigations on a group of welders exposed to Al concentrations between 5 and 10 mg/m3. It was confirmed that not only the environmental Al concentrations but also certain chemical and physical characteristics (particle size, allotropic state, solubility), simultaneous exposure to other dusts, and mode of exposure (existence of exposure peaks) play a significant role in lung absorption of Al. Urinary Al (AlU) may be considered as an indicator of "recent" exposure with biphase excretion kinetics influenced also by duration of exposure, whereas Al in serum (AlS) can probably furnish indications both on overall exposure and on body burden. In low-level Al exposure (below 0.5 mg/m3), these indicators (especially AlU) permit differentiation of the exposed groups from the general population without, however, any clear relationship with the various environmental Al concentrations. It was also seen that AlU increased with increasing work seniority and was more marked in certain processes, such as casting, and in the first few months or years of work.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗