Visceral leishmaniasis: a lingual presentation in a patient with HIV infection.

The term leishmaniasis covers a series of illnesses caused by the protozoan Leishmania; depending on the patient's immune response, the particular species of the protozoan, and the geography, the condition may manifest itself as cutaneous, mucocutaneous, or visceral disease. Visceral leishmaniasis has often been found as a co-infection associated with the human immunodeficiency virus, particularly in the region of the western Mediterranean. We report the case of an HIV-infected patient with a history of treated laryngeal leishmaniasis who subsequently appeared for treatment with a tumorous lesion on the dorsum of the tongue that was caused by Leishmania infection.

Differential pulse voltammetric determination of sumatriptan succinate (1:1) in a tablet dosage form.

A voltammetric study of the oxidation of sumatriptan succinate (1:1) has been carried out at the glassy carbon electrode. This compound exhibited a single wave in Britton-Robinson buffer solutions of pH 2-11, with a maximum current at pH 5.0. The mechanism of oxidation was shown to be due to oxidation of the N-H group in the indole ring. Based on this study, a simple, rapid and sensitive voltammetric method was developed for the determination of the drug in a tablet dosage form.

Adsorptive voltammetric behaviour of immunoglobulin M.

The adsorptive voltammetric behaviour of immunoglobulin M (IgM) has been investigated at the static mercury drop electrode. The stripping process yields an analytically useful signal and the detection limit is 1.2 x 10(-10)M. The adsorptive voltammetric behaviour of IgM has been compared with that of IgG and streptavidin.

Application of adsorptive voltammetry to assess the stability of modified alanine aminotransferases.

Alanine aminotransferase has been stabilized by using chemical modification with both bis(imidates) (of varying length) and succinic anhydride. The voltammetric behavior of the native enzyme and its various modified forms has been studied by using both cyclic voltammetry and differential pulse adsorptive voltammetry. A distinctive accumulation pattern was found for each of the stabilized enzymes at the static mercury drop electrode with respect to the native alanine aminotransferase. Adsorptive voltammetry was demonstrated to be a useful technique to assess the extent of chemical modification of this enzyme, which is indirectly related to their stability for use in biotechnological processes. The sue of differential pulse adsorptive voltammetry, after a preconcentration of the enzyme for 300 s at the electrode surface, has yielded a detection limit of 1.0 x 10(-9) M.

Purification of human glutamate dehydrogenase (GDH) and an adsorptive voltammetric investigation of the interaction of GDH with rabbit anti-human GDH antibody.

A procedure for the isolation of glutamate dehydrogenase (GDH) from human liver, which involves the use of ion-exchange chromatography on diethylaminoethyl cellulose and affinity chromatography on guanosine triphosphate conjugated to Sepharose 4B, is described. The adsorptive voltammetric behaviour of human GDH, bovine GDH and rabbit anti-human GDH antibody was optimised with respect to accumulation potential, accumulation time and scan rate. The lower limits of detection were 0.2 and 1.2 mg l-1 for human and bovine GDH, respectively, and the lower limit of detection for rabbit anti-GDH antibody was 0.04 mg l-1. The interaction of human GDH with rabbit anti-human GDH antibody was also examined using this method.

Adsorptive voltammetric investigation of the interaction of cisplatin with cystine and human serum albumin.

The interaction of the anti-cancer drug cisplatin with human serum albumin and cystine has been investigated using differential pulse adsorptive voltammetry. Based on an understanding of the voltammetric behaviour of these biological molecules, which rely on the presence of the disulphide groups within their molecular structure for their electroactivity, it has been postulated that binding of cisplatin to these molecules occurs at the disulphide bond. A fractional coefficient for the binding of cisplatin to human serum albumin at pH 7.4 was calculated to be 0.32. The reactivity of hydrolysis products of cisplatin was shown to be greater than that of the parent drug.

Adsorptive stripping voltammetric assay of folic acid in human serum.

Folic acid was voltammetrically measured after preconcentration by adsorption at the static mercury drop electrode. Phase selective AC voltammetry provided the most sensitive stripping signal. After previous analyte extraction, using liquid-solid extraction with a C-18 reversed phase cartridge, the method was suitable for folic acid measurement in human serum. The detection limit was 5.9 x 10(-9) M with an overall precision of 9.9% (R.S.D.; n = 7) at the concentration level of 1.0 x 10(-7) M with a mean recovery of 57%.