Relations between combined oral contraceptive therapy and indices of autonomic balance (baroreflex sensitivity and heart rate variability) in young healthy women.

INTRODUCTION: There are structural and functional links between autonomic nervous and endocrine systems. Derivatives of estrogens and gestagens applied in combined oral contraceptives (COC) reduce the production of endogenous sex steroids, but their effect on autonomic nervous system remains unknown. AIM: To compare indices of heart rate variability (HRV) and baroreflex sensitivity (BRS) among young healthy women taking vs. non-taking COC. MATERIAL AND METHODS: We performed a cross-sectional study in a group of 53 healthy women (age: 23 +/- 3 years, BMI: 22.3 +/- 2.8 kg/m(2)) taking COC for > or = 3 months (COC-group) and in a group of 113 healthy women (age: 24 +/- 4 years, BMI: 22.0 +/- 3.1 kg/m(2)) not taking COC for > or = 3 months (n-COC-group). All examined women were between the 4th and the 8th day of menstrual (or pill-driven) cycle lasting from 21 to 35 days. Indices of autonomic balance was assessed based on the time- and frequency- domains of heart rate variability (HRV very low (VLF), low (LF), high (HF) frequencies and total HRV spectrum). BRS was evaluated using the sequence (BRS-Seq) and the controlled breathing (BRS-CtBr) methods. RESULTS: There were no differences in: age, weight, height, measures of adiposity and fat distribution, the menstrual (or pill-driven) cycle day on the day of examination, heart rate and HRV parameters between the two studied groups (all p > 0.1). BRS-CtBr was higher among n-COC-group as compared to COC-group (20.00 +/- 6.28 versus 18.07 +/- 6.57 ms/mmHg, p < 0.05). There was a trend towards higher BRS-Seq in the n-COC-group as compared to the COC-group (19.4 7 +/- 7.85 versus 16.95 +/- 5.76 ms/mmHg, p = 0.12). In the n-COC-group, BRS-CtBr and RMSSD were inversely related to age (r = -0.23, r = -0.19, p < 0.05). In the COC-group, SDNN was inversely related to waist circumference and WHR (respectively r = -0.34 and r = -0.35, both p < 0.05). CONCLUSIONS: COC impair the reflex regulation of cardiovascular system based on baroreflex, which may indicate unfavorable influence of COC use on women health. The exact mechanism of BRS impairment caused by COC remains unknown, also in the context of the different composition of various COC. Thus, it needs to be studied further

[Diagnostic scintigraphy and effectiveness of 131I radioiodine therapy in differentiated thyroid carcinoma (DTC)]. / Scyntygrafia diagnostyczna a skutecznosc leczenia zrósnicowanego raka tarczycy (DTC) radiojodem 131I.

INTRODUCTION: Since the effect of pre-therapeutic scintigraphy on the outcome of DTC treatment is debated, we evaluated factors affecting the effectiveness of (131)I therapy with respect to the delay between diagnostic scintigraphy and the application of radioiodine. MATERIAL AND METHODS: In the studied group of 60 patients with DTC, mean age 54.6 +/- 13.0 years, four weeks prior to the planned diagnostics, L-thyroxine was withdrawn and the following tests performed: (131)I (4 MBq) uptake above the neck, thyroid volume by USG, TSH and hTg level. Wholebody scintigraphy (37 MBq) was performed. The time between this diagnostic scintigraphy and application of (131)I (3657 MBq) was calculated. Based on whole-body 131I scintigraphy (74 MBq) performed 1 year after radioiodine treatment, the patients were divided into: group I - 42 patients with no tracer accumulation, and group II--18 patients who continued to accumulate (131)I in the neck. RESULTS: The differences between the median values of (131)I uptake and of thyroid volumes, and between the TSH and hTg median values in the two groups of patients were found not to be statistically significant. The average times between diagnostic scintigraphy and (131)I treatment in group I and II (9.4 vs. 8.3 weeks, respectively) were not significantly different either. CONCLUSION: Despite the different effectiveness of supplementary (131)I treatment, patients in group I and group II showed no statistically significant differences in the studied parameters. It appears that the diagnostic (131)I activity of 37 MBq and the time between diagnostic scintigraphy and application of (131)I did not have any effect on the results of the treatment in our group of patients.