Conformational study of proteins by SAXS and EDXD: the case of trypsin and trypsinogen.

The radius of gyration (Rg) of bovine trypsinogen and beta-trypsin was measured by an energy-dispersive X-ray technique (EDXD) and by small-angle X-ray scattering (SAXS), under different solvent conditions. Both techniques gave superimposable results. The experimental evidence demonstrated that: (1) no structural modifications and/or damage occurred during the data acquisition by EDXD; (2) at pH 4 the active enzyme has one class of chloride binding sites in common with the zymogen, whereas the latter protease shows an additional class able to reverse the effects on Rg induced by chloride at low concentration; and (3) the pH profile of the Rg of both proteases does not resemble at all the pH effect on beta-trypsin activity, a result in line with the finding that the electrical potentials induced by surface charge are small in absolute magnitude and produce no gradient across the active site.

[Instrument for the functional evaluation of disability rehabilitation. Study on the reliability and clinical experience with the use of functional independence measure]. / Instrumento de evaluación funcional de la discapacidad en rehabilitación. Estudio de confiabilidad y experiencia clínica con el uso del functional independence measure.

BACKGROUND: The Functional Independence Measure (FIM) is an instrument widely used to assess the results and progress of a medical rehabilitation program. AIM: To assess the inter rater agreement in the application of FIM and show the clinical experience with its use in disabled patients enrolled in a rehabilitation program. PATIENTS AND METHODS: FIM was applied in 40 patients and the inter rater agreement was assessed, comparing raters with and without training in its use. Agreement was evaluated using Kappa test. Afterwards, the FIM was used to assess changes in 100 patients hospitalized and being rehabilitated at the Rehabilitation ward of a general hospital. RESULTS: Inter rater agreement is high in physical areas of the FIM and low in cognitive areas. Training significantly improves agreement in communication and cognitive areas. During a mean period of hospitalization of 38 days, FIM score changed from a mean of 47.2 to 92 points, with an improvement of 1.18 points per hospitalization day. The higher improvement was achieved in the physical area of the instrument. CONCLUSIONS: Training is required for a proper application of FIM. When used adequately, this instrument allows an assessment of the degree of disability and the changes obtained with rehabilitation programs.

Structural differences of ovalbumin and S-ovalbumin revealed by denaturing conditions.

We found, by circular dichroism and Raman spectroscopy measurements, that the secondary structure of the native ovalbumin and of its heat-stable form, called S-ovalbumin, is a probe of the structural differences between the two proteins. Small angle X-ray scattering and circular dichroism measurements performed on the two proteins under denaturing conditions, with different concentrations of guanidine hydrochloride, show the changes of the tertiary and secondary structure and a different pathway in the unfolding process. These experimental data confirm that the conversion of native ovalbumin into S-ovalbumin is irreversible and reveal that the response of the two proteins to the same chemical environment is different.

Conformational changes involved in the switch from ovalbumin to S-ovalbumin.

For the first time a comparative study on conformational differences between native ovalbumin and its heat-stable form, called S-ovalbumin, using small angle x-ray scattering, is reported. To detect a different pathway in the folding mechanism of the two proteins, scattering measurements have been performed on ovalbumin and S-ovalbumin denatured with different concentrations of guanidine hydrochloride, and by heating the proteins at acid pH. The intensity scattering curves provide evidence that the intermediate states in the unfolding process are globular for both proteins while their compactness changes. The reported experimental results suggest that the ovalbumin to S-ovalbumin transformation can be considered a protein-switch triggered by changes in the chemical conditions of the protein environment. Because the conformational changes are likely to be of functional importance, we infer that the occurrence in vivo of S-ovalbumin is thus determined by the transformation of ovalbumin, with a functional role for embryonic development, into a new protein with a different function.

[Oral mucosa and hormonal stimulation during the menstrual cycle]. / Mucosa orale e stimolazione ormonale durante il ciclo mestruale.

This study valued by Eosinophilic Index (EI) or cellular maturation index the behaviour of oral mucosa cells undergoing stimulus of hormones during menstrual cycle, as well as vaginal cells according to a supposition by several Authors. Specimens by scraping of oral mucosa cells in female patients selected by standards of regular menstrual cycle and absence of any oral pathology or dental prosthesis, actually showed EI changes according to cycle stage and rate of hormonal effect probably. On the other hand, specimens by scraping or oral mucosa cells in male patients showed constant EI rates during monthly cycle. Being statistical study not significant because of little series of specimens--it's difficult to select a lot of women and to control them during their whole menstrual cycle working in a small surgery! -, yet Authors confirm results of previous studies by different Authors. If the relationship between cellular maturation of oral cells and effect of hormones during menstrual cycle resulted, it could be possible further on to investigate, for example, the behaviour of epithelial cells being in any periodontal pocket undergoing stimulus of female hormones.