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Biomedical subjects

B Roldán

Publications and source records attributed to B Roldán.

4 recordsLinked to original sources

Improvements in europium sensitized fluorimetric determination of demeclocycline and methacycline.

Demeclocycline (DM) and methacycline (MT) have been determined by europium-sensitized fluorescence, using EDTA as co-ligand and cetyltrimethylammonium chloride as surfactant. The methods have been developed in slightly alkaline solutions, with the formation of a new chelate where the lanthanide ion is bound to the beta-diketone group. Calibration graphs between 0.01 and 0.1 microg mL(-1) have been obtained for DM and MT determination. Both methods have been applied to the determination of these tetracyclines in serum samples with satisfactory recovery results.

Demeclocycline↗

High prevalence of the polycystic ovary syndrome and hirsutism in women with type 1 diabetes mellitus.

The current recommendation for strict metabolic control of type 1 diabetes mellitus requires the administration of supraphysiological doses of insulin, which might result in insulin-mediated stimulation of androgen synthesis, as occurs in insulin-resistant states. At present, the prevalence of hyperandrogenic disorders in women with type 1 diabetes mellitus is unknown. Eighty-five women with type 1 diabetes mellitus were evaluated for symptoms and signs of hyperandrogenism. In 68 of the patients, several serum androgen and hormone concentrations were measured. The polycystic ovary syndrome (PCOS) was defined by the presence of menstrual dysfunction, together with clinical and/or biochemical evidence of hyperandrogenism, and exclusion of other etiologies. Eighteen healthy women, menstruating regularly, served as controls for the androgenic profiles. Thirty-three patients (38.8%) presented hyperandrogenic disorders (16 had PCOS, and 17 had hirsutism without menstrual dysfunction). Type 1 diabetic patients with PCOS presented increased serum total and free testosterone concentrations, and serum androstenedione levels, but had normal serum sex hormone-binding globulin and dehydroepiandrosterone-sulfate levels. Hirsute type 1 diabetic women without menstrual dysfunction presented normal serum androgen levels. There were no significant differences between hyperandrogenic and nonhyperandrogenic type 1 diabetes mellitus women in clinical variables such as the duration of diabetes, age at diagnosis of diabetes, conventional or intensive insulin therapy, mean daily insulin dosage, or metabolic control. In conclusion, women with type 1 diabetes mellitus have a high prevalence of hyperandrogenic disorders, including PCOS and hirsutism.

Adult↗

[Long-latency auditory evoked potentials in cochlear implants].

Cortical evoked potentials were evaluated in patients with cochlear implants. In a group of 8 adults of different ages, the lingual state before implantation and during rehabilitation were evaluated. Using cortical evoked potentials, the results of the P300 wave in response to two tones, one frequent (1,000 Hz) and the other infrequent (2,000 Hz), presented at 70 and 80 dB HL were studied. Results were analyzed and compared in relation to locutive state, rehabilitation stage, and intensity of stimulus. Absolute latencies did not differ significantly. However, latency values in relation to reaction time were significantly longer in prelingual than in postlingual patients (p < 0.05, Student < > test). The results confirmed the normality of central cognitive processes in patients with cochlear implants in objective assessment of P300 latency. The results suggest differences between prelingual and postlingual patients in relation to central signal processing.

Acoustic Stimulation↗