Erythema elevatum diutinum mimicking porphyria cutanea tarda

A case of erythema elevatum diutinum (EED) closely resembling porphyria cutanea tarda (PCT) is reported. The initial skin biopsies were suggestive for PCT but porphyrin levels in the urine, stool and plasma were normal. A further biopsy from an early cutaneous lesion showed a leucocytoclastic vasculitis with fibrinoid necrosis of the vessel walls.     

Development of a novel resin with antimicrobial properties for dental application

The adhesion of biofilm on dental prostheses is a prerequisite for the occurrence of oral diseases.

Objective

To assess the antimicrobial activity and the mechanical properties of an acrylic resin embedded with nanostructured silver vanadate (β-AgVO₃).

Material and Methods

The minimum inhibitory concentration (MIC) of β-AgVO₃ was studied in relation to the species Staphylococcus aureus ATCC 25923, Streptococcus mutans ATCC 25175, Pseudomonas aeruginosa ATCC 27853, and Candida albicans ATCC 10231. The halo zone of inhibition method was performed in triplicate to determine the inhibitory effect of the modified self-curing acrylic resin Dencor Lay - Clássico^®. The surface hardness and compressive strength were examined. The specimens were prepared according to the percentage of β-AgVO₃ (0%-control, 0.5%, 1%, 2.5%, 5%, and 10%), with a sample size of 9x2 mm for surface hardness and antimicrobial activity tests, and 8x4 mm for the compression test. The values of the microbiologic analysis were compared and evaluated using the Kruskal-Wallis test (α=0.05); the mechanical analysis used the Shapiro-Wilk''s tests, Levene''s test, ANOVA (one-way), and Tukey''s test (α=0.05).

Results

The addition of 10% β-AgVO₃ promoted antimicrobial activity against all strains. The antimicrobial effect was observed at a minimum concentration of 1% for P. aeruginosa, 2.5% for S. aureus, 5% for C. albicans, and 10% for S. mutans. Surface hardness and compressive strength increased significantly with the addition of 0.5% β-AgVO₃ (p<0.05). Higher rates of the nanomaterial did not alter the mechanical properties of the resin in comparison with the control group (p>0.05).

Conclusions

The incorporation of β-AgVO₃ has the potential to promote antimicrobial activity in the acrylic resin. At reduced rates, it improves the mechanical properties, and, at higher rates, it does not promote changes in the control.     

Bioorganic stereochemistry. A study of the peptide oxazolones from Z-(Aib)n-OH (n = 2–4) in the solid state*

An investigation of the preferred conformations and modes of self-association of the peptide oxazolones from Z(-Aib-)_n-OH (n = 2–4) in the solid state has been performed by infrared absorption. More detailed information on the peptide oxazolone from Z(-Aib-)₃ OH (2) has been obtained using X-ray diffraction. In this compound the conformations of the first two Aib residues differ substantially, only the N -terminal one being found in the usual 3_10- (or α-) helical region of the Ramachandran map. The C=N-bond of the oxazolone group is not conjugated with the lactone moiety. A very weak intermolecular interaction occurs between the urethane N-H and the carbonyl group of the oxazolone ring.