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Biomedical subjects

C Lupi

Publications and source records attributed to C Lupi.

8 recordsLinked to original sources

Encephalitis without meningitis due to sandfly fever virus serotype toscana.

The role of Toscana (TOS) virus in producing encephalitis without meningitis is uncertain. We studied 2 cases of TOS virus encephalitis without meningitis by means of nested polymerase chain reaction assay and DNA sequencing. Findings confirm that TOS virus may directly cause encephalitis and suggest the usefulness of DNA sequencing in investigating relationships between TOS virus molecular patterns and the spectrum of neurological involvement.

Adult↗

Soluble CD30 antigen in human colostrum.

It is now well established that the CD30 glycoprotein is a surface antigen expressed by activated T cells producing T-helper (Th)-2-type lymphokines. Mounting laboratory evidence, however, suggests that CD30 expression is not confined to a functionally restricted subset of T cells, but also identifies activated cells with a Th-1 and Th-0 pattern of cytokine secretion. CD30-bearing T lymphocytes release a soluble form of the molecule (sCD30), which can be detected both in vitro and in vivo. In the present study, very high levels of sCD30 were found in colostrum from 20 puerperal women, but not in autologous and heterologous (nonpregnant women) blood samples. These data strongly support an involvement of CD30+ T cells in the immune processes which take place at the level of the mammary gland during pregnancy and lactation. Passively transferred immune components such as immunoglobulins, cytokines, macrophages, natural killer cells, granulocytes and memory/activated T cells, all of which may help the baby to fight off infections, have been revealed in human breast milk. However, how Th-2-type cytokine-secreting T cells or other T-cell types help to endow the congenitally immunocompromised newborn infant with extrinsic immunological support remains an open question.

Colostrum↗

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↗

Reproducibility of low-dose extrapolation procedure: comparison of estimates obtained using different rodent species and strains.

Carcinogenic risk assessment based on low-dose extrapolation of dose-response relationships is characterized by a significant level of uncertainty. The aim of this study was to investigate the reproducibility of risk estimates carried out using different animal species and strains. The Weibull and multistage mathematical modes, as well as the "linearized multistage" model (EPA "conservative" procedure), have been used for dose-response relationship fitting. Whenever necessary, the Michaelis-Menten function was introduced in the models to account for a possible metabolic process. The analysis was directed to dietary sodium saccharin and vinyl chloride inhalation carcinogenicity (nine total dose-response relationships). Data from different strains, species, and researchers were available for these substances. The general pattern of two sodium saccharin curves was an upward curve in both cases with a high consistency among parameters and risk estimates (the latter ranging within a factor 3). For vinyl chloride the trend was clearly downward for six carcinogenic dose-response relationships from different species; low-dose risk estimates, based on the upper confidence limits of the linear component, range within a factor 3. The study has indicated the reproducibility of the low-dose extrapolation process using different strains and species.

Animals↗

Dose-response relationships in rodents of promoter carcinogens: a tentative interpretation of some downward trends.

This study analyzes a set of dose-response curves relative to promoter carcinogens administered to experimental animals with or without initiator pretreatment. In the case of initiator plus promoter treatment, as well as for low experimental doses, the experimental data and their mathematical fitting indicate a downward shape of the dose-response curves as a general feature. In this study, the following hypothesis, according to the two-stage carcinogenic action of initiator plus promoter treatment, is presented to interpret this downward shape: (i) an initiating action, involving a subset of available "targets" (the number of "initiated" targets is assumed to depend on initiating treatment level), and (ii) a subsequent dose-dependent promoting process, mainly involving the initiated targets. This process reaches a saturation level when all the initiated targets have been promoted. This kind of process may be quantitatively described by a saturated exponential model: P(d) = K(1 - exp(-K0 + K1d)] which fits the experimental data fairly well. No indication supporting the hypothesis of a threshold for the chemicals examined resulted from the analysis. In the specific case of sodium saccharin, experimental dose-response relationships were available with or without initiator pretreatment (BBN and MNU). While in the first case the shape of the dose-response curve is downward, in the second case, it is upward and significantly different.

Animals↗

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History, Modern 1601-↗