The effect of prior antithyroid drug use on delaying remission in high uptake Graves' disease following radioiodine ablation.

Antithyroid drugs (ATDs) have been shown to attenuate the effectiveness of radioiodine (radioiodine ablation, RIA) therapy in Graves' disease. We undertook a study to look at the impact of iodine uptakes on the outcome of (131)I therapy. To determine the effect of prior ATD use on the duration of time to achieve cure in patients with high vs intermediate uptake Graves' disease who received a fixed dose (15 mCi) of (131)I radioiodine. In a retrospective study of patients with Graves' disease, 475 patients who underwent RIA were followed-up on a two-monthly basis with thyroid function tests. Of the 123 patients with a documented preablation RAIU and consistent follow-up it was observed that 40 patients had an intermediate RAIU (10-30%) and 83 subjects had a distinctly increased uptake (>30%). Successful cure was defined as the elimination of thyrotoxicosis in the form of low free thyroxin and rising TSH levels. When a standard dose of 15 mCi (131)I was administered, a cure rate of 93% was achieved. The median duration of time to cure (TC) was 129 days. Surprisingly, a direct proportional linear relationship (R(2)=0.92) was established between time to cure and radioiodine uptake (TC> 3 0%=172days, TC10 - 3 0%=105 days, P<0.001). Patients who used ATD medications took a proportionately longer duration to achieve remission (TCNO ATD=102days, TCATD=253days, P<0.001). The effect of prior ATD therapy in delaying remission was amplified in the subset of patients with higher uptakes (TC> 3 0% + ATD=310days, TC> 3 0% + NO ATD=102days, P<0.001) compared to those with the intermediate uptakes (TC10 - 3 0% + ATD=126 days, TC10 - 3 0% + NO ATD=99 days, P<0.001). RIA, using a dose of 15 mCi achieved a high cure rate. Higher uptakes predicted longer time to achieve remission, with prior ATD use amplifying this effect.

Effect of cigarette smoking on nasal mucociliary clearance: A comparative analysis using saccharin test.

BACKGROUND: Nasal mucociliary clearance (NMC) system transports the mucus layer covering the nasal epithelium towards nasopharynx by ciliary beating at a frequency of 7-16 Hz. NMC is altered by septal deviations, upper respiratory infections, and drugs. Few studies have revealed significant depression of ciliary activity in smokers. We conducted this study to compare NMC and influence duration of smoking on NMC in adult smokers and nonsmokers using saccharin test. MATERIALS AND METHODS: Our study included 30 nonsmokers and 30 smokers (21-40 years) who were not on any medications and had no history of any systemic illness. Time elapsing until the first experience of sweet taste at posterior nasopharynx, following placement of saccharin particle approximately 1 cm behind the anterior end of inferior turbinate was recorded as NMC time in minutes using standard method described by Anderson. Mean NMC of both groups were compared using Student's t-test and influence of duration was analyzed by one-way Analysis of variance (ANOVA). RESULTS: NMC was significantly prolonged in smokers (481.2 ± 29.83; P < 0.01) in comparison to nonsmokers (300.32 ± 17.42 s). A statistically significant increase in NMC was observed with an increase in duration of smoking habit (NMC in smoking <1 year = 492.25 ± 79.93 s, 1-5 years = 516.7 ± 34.01 s, >5 years = 637.5 ± 28.49 s; F statistic = 20.8968, P = 0.0000). CONCLUSIONS: NMC measurement is a simple and useful index for the assessment of effect of smoking on the ciliary activity of respiratory mucosa. Prolonged clearance observed in smokers of our study may be due to slowed ciliary beat frequency or reduction in number of cilia and changes in viscoelastic properties of mucus.