Application of fluorescence spectroscopy and chemometric models for the detection of vegetable oil adulterants in Maltese virgin olive oils.

Fluorescence spectrometry, combined with principle component analysis, partial least-squares regression (PLSR) and artificial neural network (ANN), was applied for the analysis of Maltese extra virgin olive oil (EVOO) adulterated by blending with vegetable oil (corn oil, soybean oil, linseed oil, or sunflower oil). The novel results showed that adjusted PLSR models based on synchronised spectra for detecting the % amount of EVOO in vegetable oil blends had a lower root mean square error (0.02-6.27%) and higher R2 (0.983-1.000) value than those observed when using PLSR on the whole spectrum. This study also highlights the use of ANN as an alternative chemometric tool for the detection of olive oil adulteration. The performance of the model generated by the ANN is highly dependent both on the type of data input and the mode of cross validation; for spectral data which had a variable importance plot value > 0.8 the excluded row cross validation was more appropriate while for complete spectral analysis k-fold or CV-10 was more appropriate.

Visceral leishmaniasis in Malta--an 18 year paediatric, population based study.

BACKGROUND: Visceral leishmaniasis (VL) is a chronic parasitic infection that infects approximately 400,000 individuals annually, with a predilection towards early childhood. AIMS: To study the epidemiology of VL in childhood. METHODS: VL is endemic in Malta, a small archipelago of islands in the centre of the Mediterranean with a total population approaching half a million. Notification of human cases of leishmaniasis is compulsory. Case records of all 81 paediatric patients with VL between 1980 and 1998 were analysed. RESULTS: The annual incidence of VL declined for all cases of VL, and declined significantly for paediatric cases (p = 0.01). For 1994 to 1998, the overall incidence of VL was 0.9 per 100,000 total population and the paediatric incidence was 2.5 per 100,000 population. Median age at presentation was 34 months. Common features at presentation were splenomegaly, hepatomegaly, fever, and pancytopenia with high lymphocyte and monocyte counts. The diagnostic sensitivity of isolated immunofluorescent antibody testing was equivalent to bone marrow aspiration (95%). Blood transfusions for anaemia were required in 93% of patients. Eleven per cent had intercurrent infections. All patients were cured, and were initially treated with intravenous sodium stibogluconate. Defervescence occurred after a median of six days of treatment, and patients continued to be treated on a day case basis. Nine relapsers were retreated with sodium stibogluconate, achieving a cure rate of 94%, but five patients required additional drug therapy. There were no permanent sequelae associated with VL or its treatment. CONCLUSIONS: The decreased incidence is attributed to the eradication of stray dogs which are the disease reservoir.

Resolution, absolute configuration, and antiarrhythmic properties of the enantiomers of disopyramide, 4-(diisopropylamino)-2-(2-pyridyl)-2-phenylbutyramide.

Disopyramide was resolved by fractional crystallization of its diastereomeric bitartrate salts from methanol-acetone. Diastereomeric sulfonamides prepared from (+)-camphor-10-sulfonyl chloride and the primary amines obtained by LiAlH4 reduction of the resolved bases were separable by high-performance LC and were used to show that within experimental error resolution of disopyramide was complete. The absolute configuration was determined by X-ray crystallography. (+)-[(2R)-(-)-4-(Diisopropylamino)-2-(2-pyridyl)-2-phenylbutyramide (+)-(2R,3R)-bitartrate] crystallizes in space group P212121: a = 14.789 (4), b = 18.151 (4), c = 9.878 (2) A; Z = 4: Dx = 1.225, Dm (flotation C6H6/CCl4) = 1.226 g cm-3. The structure was solved by direct methods. The enantiomeric bitartrates were tested for antiarrhythmic properties. The enantiomeric bitartrate salts were equally effective in prolonging the effective refractory period (ERP) of rabbit ventricle. At 3 x 10(-6) M, the (-)-bitartrate [from (2S)-(+)-disopyramide] increased the ERP 21.8 +/- 6.3 ms and the (+)-bitartrate [from (2R)-(-)-disopyramide] increased the ERP 25.8 +/- 3.6 ms. At 1.5 x 10(-5) M no significant difference was noted, as the increases in the ERP were 41.2 +/- 8.9 and 50.5 +/- 6.3 ms for the (-)- and %+)-bitartrate, respectively.