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Biomedical subjects

M Trotta

Publications and source records attributed to M Trotta.

60 records · Page 4Linked to original sources
PubMedDate not supplied

Vitamin A palmitate photostability and stability over time.

Vitamin A palmitate photostability in relation to UVA and UVB was tested in hydroxy ethyl cellulose hydrogels at pH 4.0, 5.6, 7.0, and 8.0, alone and with the addition of sunscreens (3,4-methylbenzilidencamphor or butyl methoxy dibenzoylmethane) or an antioxidant (butylated hydroxy toluene). The photostability of vitamin A palmitate was also tested in encapsulated systems (Tagravit A1 microcapsules, Lipotec liposomes, phosphatidylcholine liposomes, and Lipotec nanocapsules) dispersed in gels at pH 5.6 and 7.0. The stability of retinyl palmitate over time in hydroxy ethyl cellulose hydrogels at pH 5.6 and 7.0 (stored one month at 25 degrees C or 40 degrees C), alone or with butylated hydroxy toluene, was also tested. The stability of retinyl palmitate over time in encapsulated systems, dispersed in gels at pH 5.6 and 7.0, was also studied. O/W emulsions were also prepared to compare the stability of vitamin A palmitate introduced in a lipophilic/hydrophilic medium (O/W emulsions) and a hydrophilic medium (hydrogels). HPLC analysis showed that encapsulated systems such as Lipotec nanocapsules, Tagravit A1 microcapsules, phosphatidylcholine liposomes, and Lipotec liposomes protect the vitamin A ester over time from hydrolysis and from oxidation to retinaldeide and retinoic acid, and that Lipotec nanocapsules and phosphatidylcholine liposomes also improve the vitamin's photostability. A change in pH (from 5.6 to 7.0) of the gels did not influence the vitamin ester's stability. pH levels of 4.0 and 8.0 determined a decrease in the stability of retinyl palmitate in the gels. A high concentration of sunscreens improved the photostability of retinyl palmitate in the gels at pH 5.6 and 7.0. Butylated hydroxy toluene protected retinyl palmitate from degradation induced by light at all the pH levels studied and by heat at pH 5.6 and 7.0, as can be seen from the study of the photostability of vitamin A palmitate under UVB and UVA and of stability over time. Rheological studies showed a slight decrease in the viscosity of the gels after UVB-UVA irradiation and a higher decrease in the viscosity of the gels and the emulsions after storage at 25 degrees C and 40 degrees C. This decrease can be attributed to a partial degradation of hydroxy ethyl cellulose and of emulsifier, as can be seen from the decrease in shear stress versus shear rate values under these conditions of storage, denoting a depolymerization of the rheological modifier.

Animals↗
PubMedDate not supplied

[Histologic and immunologic study of recurring endonasal polyposis in relation to desensitization therapy].

Ten middle-aged patients (7 males and 3 females) suffering allergic rhinitis and endonasal polyposis, were polypectomized and studied with allergoimmunologic techniques. Clinical evaluation preceded laboratory examinations consisting in routine data and electrophoretic study of serum proteins. These examinations were performed before and after one-year hyposensitization treatment. One patient revealed a hypogammaglobulinemia and received 800 mg of commercial human gammaglobulin every 28 days, during 3 months; subsequent proteinograms showed acceptable improvement of the initial value. Skin tests resulted positive in all patients particularly to house dust, micotic (Candida albicans, Trycophyton and Alternaria) and bacterial antigens (Gram positive and negative bacteria). Specific hyposensitization was performed throughout one year with weekly subcutaneous injections of the corresponding antigens. No autovaccine of nasal exudates was employed. All the polyps were divided into two parts; one half for histological study and the other half stored at -20 degrees C for protein determination using immunoelectrophoresis, polyacrilamide gel and radial immunodiffusion. Immunoelectrophoresis was performed with polyps homo-genate against an antihuman serum and showed two precipitin lines at alfa-1 and beta-1 globulin sites. Polyacrilamide gel revealed more lines in those runs belonging to post-vaccinated polyps than in those belonging to the prevaccinated group. Immunoquant polyps were checked against anti-A, anti-G and anti-M; only IgA was detected in polyps obtained at any time. These apparently contradictory results may be due to the different sensitivity of the techniques applied as well as the small amount of polyps homogenate and its low protein content. New polyps reappeared in three patients at six, ten and twelve months, respectively, from the beginning of the treatment. These patients were again polypectomized and histological and immunological studies were repeated. They were fixed in Bouin, and paraffin sections of 6 to 10 microns in thickness, were submitted to hematoxilineosin, P.A.S. and toluidin blue techniques. These preparations were microscopically evaluated with a Carl Zeiss Photomicroscope with magnifications of 100, 250, 400 and 1,000 times. An important difference between the original and the recurrent histological images was seen. Meanwhile the former polyps were vascularly rich and cellularly poor, the latter appeared inversely composed. An abundant infiltrate of plasmocytes, lymphocytes and histocytes was the rule; it was regularly disposed but a preference to collect around the vessels was observed. The vessels seemed to be lesser in number and size though this observation must be checked with further investigations. The absence of eosinophils led us to support--in this case--the participation of an infectious mechanism in an allergic filed with high sensitivity to bacterial and inhalant antigens...

Agammaglobulinemia↗
PubMedDate not supplied

In vitro transdermal permeation of nifedipine from thickened microemulsions.

The in vitro transdermal absorption of nifedipine from microemulsions was studied using the skin of the hairless mouse as membrane. Two microemulsions (N.1 and N.2) were prepared and thickened; they contained respectively 1.8% and 2.0% of nifedipine in solution. The fluxes of the drug from the microemulsions were 7.8 micrograms/h/cm2 from N.1 and 18.6 micrograms/h/cm2 from N.2. Two reference gels were prepared to examine whether the components of the microemulsion could behave as enhancer: their fluxes were very low, below 0.5 microgram/h/cm2. Nifedipine dissolved in microemulsion and protected from light showed no degradation for up to six months.

Administration, Cutaneous↗
PubMedDate not supplied

[Differential diagnosis of fever of unknown origin. A case of adult onset Still disease].

BACKGROUND: A case of Still's disease in the adult, an uncommon seronegative rheumatoid arthritis-like disease with prominent systemic features is reported. This case did not show the typical clinical features and appeared like a fever of unknown origin. CASE REPORT: A 60 year-old female was admitted to the hospital for high fever occurred two months before without other important clinical symptoms and signs. Laboratory tests and morphologic images were negative for infectious diseases, tumours and immunological disorders. The course of the disease worsened and an hepatic failure threatened the patient life. The onset of many other typical clinical features, i.e. joints pain, characteristic skin rash, splenomegaly, throat pain, serositis and weight loss, led us to make a sure diagnosis and to save the patient with steroid therapy.

Diagnosis, Differential↗