The Effect of Melatonin on Pediatric Drug-Resistant Epilepsy; a Randomized Double Blind Clinical Trial

BackgroundAbout 15 to 40% of children with seizures are refractory to standard anti-epileptic drugs and for such patients, other treatments such as surgery and the ketogenic diet can reduce seizure frequency. Melatonin is a natural pineal gland hormone. The use of melatonin for controlling pediatric seizures is still controversial. This study aimed to evaluate the effect of melatonin on seizures, parent's satisfaction, sleep, and behavior in children with drug-resistant epilepsy.Materials and Methods: In a pilot crossover study, children with drug-resistant epilepsy, who referred to the epileptic clinic of Ghaem Hospital, were randomly assigned to receive treatment with melatonin or a placebo for 4 weeks followed by a one-day washout period. Then patients who started with melatonin were switched to the placebo. Melatonin was administered 30 minutes before bedtime at a dose of 10 mg /m2 in 3mg tablets.ResultsTwenty patients, of which 11 (55%) were male, were enrolled into the study. The range and mean age of patients were 2 to 13 years and 7.28 ± 3.46 years, respectively. The mean number of diurnal seizures in the study group during placebo treatment was 11.05 and during melatonin treatment was 6.25, which was statistically significant (P=0.021). However, the reduction of the mean duration of diurnal seizures in the study groups was not statistically significant (P=0.386). There was no correlation between decreasing in number or duration of seizures with melatonin plasma levels. Drowsiness was the only side effect of melatonin, which occurred in three patients. ConclusionMelatonin has probable beneficial effects on some epileptic patients with unclear mechanisms. Physicians can use it in selected epileptic children to improve seizures

Correction: A 99mTc-Labelled Tetrazine for Bioorthogonal Chemistry. Synthesis and Biodistribution Studies with Small Molecule trans-Cyclooctene Derivatives.

[This corrects the article DOI: 10.1371/journal.pone.0167425.]

A ^99mTc-Labelled Tetrazine for Bioorthogonal Chemistry. Synthesis and Biodistribution Studies with Small Molecule <i>trans</i>-Cyclooctene Derivatives

<div><p>A convenient strategy to radiolabel a hydrazinonicotonic acid (HYNIC)-derived tetrazine with ^99mTc was developed, and its utility for creating probes to image bone metabolism and bacterial infection using both active and pretargeting strategies was demonstrated. The ^99mTc-labelled HYNIC-tetrazine was synthesized in 75% yield and exhibited high stability <i>in vitro</i> and <i>in vivo</i>. A <i>trans</i>-cyclooctene (TCO)-labelled bisphosphonate (TCO-BP) that binds to regions of active calcium metabolism was used to evaluate the utility of the labelled tetrazine for bioorthogonal chemistry. The pretargeting approach, with ^99mTc-HYNIC-tetrazine administered to mice one hour after TCO-BP, showed significant uptake of radioactivity in regions of active bone metabolism (knees and shoulders) at 6 hours post-injection. For comparison, TCO-BP was reacted with ^99mTc-HYNIC-tetrazine before injection and this active targeting also showed high specific uptake in the knees and shoulders, whereas control ^99mTc-HYNIC-tetrazine alone did not. A TCO-vancomycin derivative was similarly employed for targeting <i>Staphylococcus aureus</i> infection <i>in vitro</i> and <i>in vivo</i>. Pretargeting and active targeting strategies showed 2.5- and 3-fold uptake, respectively, at the sites of a calf-muscle infection in a murine model, compared to the contralateral control muscle. These results demonstrate the utility of the ^99mTc-HYNIC-tetrazine for preparing new technetium radiopharmaceuticals, including those based on small molecule targeting constructs containing TCO, using either active or pretargeting strategies.</p></div

Synthesis scheme for ^99mTc-HYNIC-tetrazine-TCO-vancomycin (7) from TCO-vancomycin (6) and 4.

<p>Synthesis scheme for ^99mTc-HYNIC-tetrazine-TCO-vancomycin (7) from TCO-vancomycin (6) and 4.</p

Biodistribution data for active targeting of <i>S</i>. <i>aureus</i> infection using ^99mTc-HYNIC-tetrazine-TCO-vancomycin (7).

<p>Compounds <b>4</b> and <b>6</b> were combined prior to i.v. injection of Balb/c mice (n = 3 per time point). Select fluids and tissues were collected at 1 (gray bars) and 6 h (black bars) post injection, including the infected calf muscle (right), and the non-infected calf muscle (left). Data are expressed as the mean percent injected dose per gram (%ID/g) ± SEM. Tabulated biodistribution data can be found in the supporting information (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0167425#pone.0167425.s004" target="_blank">S4 File</a>).</p

Synthesis scheme for the actively targeted derivative, ^99mTc-HYNIC-tetrazine-TCO-BP (5).

<p>The TCO derivative of the bisphosphonate, alendronate (TCO-BP) was mixed with 4 prior to administration to mice.</p

Synthesis scheme for the preparation of 3.

<p>A protected form of HYNIC (<b>1</b>) was coupled to a commercially available tetrazine to form <b>2</b>. The Boc group was removed prior to labelling by treatment with TFA in DCM to produce <b>3</b>. Tz* = (4-(1,2,4,5-tetrazin-3-yl)phenyl) methanamine.</p

Biodistribution data for 4.

<p>Data are presented as the mean (± SEM) percent injected dose per gram (%ID/g) for selected tissues and fluids from CD1 mice at 0.5, 1, 2 and 6 h post injection (n = 3 per time point). Approximately 0.88 MBq were administered per mouse. Full biodistribution data can be found in the supporting information (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0167425#pone.0167425.s004" target="_blank">S4 File</a>).</p

Radiolabelling scheme for the HYNIC-tetrazine ligand 3 and HPLC chromatogram of the isolated product 4.

<p>^99mTc labelling of the HYNIC-tetrazine <b>3</b> (A). A γ-HPLC chromatogram of the purified final product <b>4</b> (B).</p

Binding of 4 to <i>S</i>. <i>aureus in vitro</i> using TCO-vancomycin 6.

<p><i>S</i>. <i>aureus</i> were pretreated with <b>6</b> in the absence (gray) or presence (black) of a 10-fold excess of vancomycin. The mean percentages (± SEM) of total radioactivity bound after 1 and 6 h incubation times with <b>4</b> are shown.</p