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The a-wave is one of the main issues of research in the field of ocular electrophysiology, since it is strictly connected with early photoreceptoral activities. The present study proposes mathematical methods that analyse this component in human subjects, and supports experimental evidence relating to possible correlations among the responses of photoreceptoral units under a light stimulus. The investigation is organized in two parts: the first part concerns the onset and the initial slope, up to the first minimum (about 10-15 ms), the second part deals with the main portion of the wave, up to about 30 ms. In both cases, the a-waves, recorded at various levels of luminance, have been fitted with a set of appropriate functions representing possible models of physiological behaviour which would take place in the early stages of phototransduction. The statistical nature of the underlying processes is also discussed. The results indicate that correlations occur in the early stages, whereas random processes are set up later.

The aim of this work was to perform an immunological study in six patients with 21 hydroxylase deficiency in mild form (M210HD) and in 2 patients with 21-hydroxylase deficiency in classical form (C210HD) and in their parents, in whom a previous HLA,C4,Bf typing demonstrated high prevalence of DR5 and phenotypic absence of fraction C4B of complement (C4BQO). This study contains the evaluation of C3, IgA, IgG, IgM levels, anticardiolipin antibodies (IgG and IgM) and circulating immunocomplexes. A study of lymphocyte subsets was also performed. Among M210HD 1 patient showed presence of anticardiolipin antibodies both IgM and IgG; this patient had shown antinuclear antibodies in a previous study. Among parents, some subjects showed presence of anticardiolipin antibodies and high levels of circulating immunocomplexes. No alterations in C3 and Ig levels were observed. A reduced percentage of CD4 suppressor-inducer (CD4-SI) (p<0.05 in M210HD and in parents vscontrols) and increased percentage of CD4 helper-inducer (CD4-HI) (p<0.05 in both groups vscontrols) were found. No alterations were evidenced in C210HD patients. Data about association between 21-hydroxylase deficiency and autoimmune diseases are rare. Our results confirm that 210HD could be associated to an unbalancement of immune system function and suggest that non immune genes, like 21-hydroxylase one, may influence the expression of autoimmune diseases at least in presence of peculial extended haplotypes.

HLA haplotypes, complement C4 factor and factor B immonochemical concentrations and autoantibodies titer have been studied in six patients with mild congenital adrenal hyperplasia (MC-AH), in two patients with classical congenital adrenal hyperplasia (CCAH) and in their parents. A high frequency of DR5 and C4BQO alleles have been found in MCAH patients. Moreover, C4BQO allele is carried out in three out of four cases associated with DR5. In the two CCAH patients we found a B51 and a B14 allele, the last one usually described in the non classical form of the disease in population of different ethnic origin. Signs of autoimmunity in some patients and parents have been found. C4 null alleles were several-fold more frequent among our patients with respect to the same ethnic control group and the autoantibody positivity could be the result of an altered immune regulation. The presence of a positive correlation between Cortisol basal levels and C4 and Bf concentrations in the six MCAH patients suggests an interrelationship between hormonal factors and immunological findings in this disease. Our finding about HLA antigens not previously described in this syndrome may stimulate more profound studies by genomic and cDNA probes.

The Mediterranean Sea is an area of great interest for its volcanic activities. This paper presents a comparative study of radiometric and chemical data regarding three volcanic islands located in southern Italy (Pantellena, Ustica, and Vulcano) characterized by different magmatic histories. Measurements of radionulide contents and chemical composition of rock samples belonging to the main lithologies present in the three islands were carried out the observed correlations among radiometric, chemical and mineralogical data reflect the differences in the volcanological genesis and suggest some hypotheses on the magmatic evolution.

Three of four children in a family have homozygous (less than 1% of normal) deficiency of factor H of the complement system and both parents, who are first cousins, are heterozygous for the same defect. The father and two of the H-deficient siblings also have a partial C2 deficiency. One of the children with combined deficiencies is affected by systemic lupus erythematosus with nephritis. No increased susceptibility to infections has been observed in the family. H deficiency is inherited in an autosomal codominant manner and is independently transmitted from C2 deficiency and HLA haplotypes. In the homozygous state it is associated with very low serum concentrations of B and C3, barely demonstrable as activated molecules. C5 is greatly reduced (less than 5%). Also, properdin and C6–9 are decreased. The findings in this family demonstrate that the occurrence of systemic lupus erythematosus in one of the children affected by a combined deficiency of factor H and C2 raises the question whether this pathology is related to the complete factor H or to the heterozygous C2 deficiency. Complete H deficiency is not necessarily accompanied by overt illness.

Classical and alternative complement pathway activities have been evaluated in sera of women in progressive stages of gestation and in pregnant mice belonging to outbred or inbred matings, as compared to suitable controls. While classical C pathway was found to be unmodified, the alternative one attained in pregnancy significantly higher activity levels. Results are discussed in the light of mother-conceptus relationships.

Human polymorphonuclear leukocytes were found to be able to synthetize and release substantial amounts of PGE2, when stimulated by a phagocytic stimulus such as zymosan particles coated with complement. Hydrocortisone, at a concentration of 10−5M, which proved to be effective in other biological systems, failed to inhibit phagocytosis and PG release.

The biological damages produced by ionizing radiations in tissues and cells depend on the radiation quality, besides on the dose. The discrimination of the radiation quality, which is related to the linear energy transfer (LET), interests various fields such as radiobiology, astronautic space research, radiotherapy research and accidental dosimetry.

The radiation linear energy transfer (LET), which is the energy released by ionizing radiation per path unit, arouses great scientific interest because the biological damage produced by ionizing radiation in tissues is strictly related to LET. Radiation beams with different LETs will cause different spatial energy distribution and therefore different effects inside matter.

The identification of irradiated dried fruit can be achieved by means of the electron spin resonance (ESR) spectrometry, as recommended by the European Community, since ionizing radiation induces free radicals in cellulose, a constituent of the shell. The aim of this work was to use the ESR spectrometry also as a quantitative procedure to evaluate the original dose in irradiated dried fruits, using the additive dose method. Little shell pieces, taken from nuts, chestnuts, peanuts and pistachios, were irradiated at “original” dose values in the range 1 to 8 kGy, and the ESR signal intensity was measured. Each specimen was then reirradiated with added doses of 1 kGy, and the ESR signal was measured afterwards. The mathematical relationship between the ESR signal intensity and the added dose was found; back extrapolation to the dose axis gives an estimation of the original dose. Our results show that the method gives an estimation of the original dose within ±30%. An investigation on the time stability of the ESR signal was carried out: the signal intensity decreases during the first days after irradiation, and remains almost steady afterwards. A procedure was therefore developed to take into account this signal fading when dose reconstruction is performed with the additive dose method.

The dosimetric technique described in this paper is based on electron spin resonance (ESR) detectors using an alanine–boric compound acid enriched with 10B, and beryllium oxide thermoluminescent (TL) detectors; with this combined dosimetry, it is possible to discriminate the doses due to thermal neutrons and gamma radiation in a mixed field. Irradiations were carried out inside the thermal column of a TRIGA MARK II water–pool-type research nuclear reactor, also used for Boron Neutron Capture therapy (BNCT) applications, with thermal neutron fluence from 109 to 1014 nth cm−2. The ESR dosemeters using the alanine–boron compound indicated ESR signals about 30-fold stronger than those using only alanine. Moreover, a negligible correction for the gamma contribution, measured with TL detectors, almost insensitive to thermal neutrons, was necessary. Therefore, a simultaneous analysis of our TL and ESR detectors allows discrimination between thermal neutron and gamma doses, as required in BNCT.

In several laboratories all around the world, electron spin resonance (ESR) dosimetry is a well-established reference dosimetric system in industrial applications of ionising radiation, and its use is also proposed in radiation therapy and accident dosimetry. In the present experimental investigation preparation procedures of alanine-polyethylene solid state dosemeters with optimised characteristics were defined, both modifying the commonly used blend composition and preparation, and choosing the best ESR spectra recording conditions; some other amino acids that could be alternatives to alanine in obtaining ESR dosemeters with better performances than alanine ones were also tested. Results obtained up to now (the research is still under way) confirm that alanine seems to be the most suitable material for ESR dosimetry. Methods to improve reproducibility are also discussed.

The proton response of LiF:Mg,Ti (TLD-100) and alanine dosemeters (prepared at the Istituto Superiore di Sanit�, Rome, Italy) was studied. The irradiations were performed with proton beams with initial energies of 26.6 MeV and 18 MeV at various depths in a PMMA phantom. Results were compared with reference dosimetry provided by a Markus parallel-plate ionisation chamber and with TRIM range-effect calculations. A significant energy dependence of response was observed. The effectiveness relative to 60Co of both dosemeters was evaluated.

Thermoluminescence (TL) dosemeters, placed about 1 m above the ground in selected outdoor sites, provide a simple tool for the measurement of the dose, due to both natural and man-made radiation, in the environment. Since the radiation doses to be monitored are usually low (0.3 to 0.8 mGy per year) the TL chips required for long-term dose measurements should be more sensitive, stable and inert to extreme climatic variations than those used for other applications. Comparison between the main features of two TL dosimetric materials, LiF:Mg,Ti(TLD-100) and LiF:Mg,Cu,P (GR200A), are reported. The field application was performed during a survey in the island of Pantelleria.