GnRH analog is ineffective in increasing adult height in girls with puberty onset after 7 years of age: a systematic review and meta-analysis

Objective We assessed the effectiveness of puberty blockade with a gonadotropin-releasing hormone (GnRH) analog in increasing adult height (AH) in girls with puberty onset between 7 and 10 years of age. Methods We performed a systematic review and included controlled studies in which girls with early puberty (EP) were assigned to the GnRH analog or no treatment groups. The primary outcome analyzed was AH. Search strategies were applied to the MEDLINE, EMBASE, LILACS and CENTRAL databases. Results We identified 1514 references, and six studies fulfilled our eligibility criteria. Two studies were randomized and four were not randomized. At the baseline of each trial, height, chronological age, bone age, predicted AH (PAH) and target height (TH) were equal between the groups. All studies used intramuscular triptorelin every 28 days in the intervention groups. The mean duration of the therapy was 2 years. Meta-analysis of AH among the six studies (comprising 332 girls) showed no significant difference between the groups (mean difference = 0.50 cm, 95% confidence interval = -0.72 to 1.73 cm, I 2 = 0%). In a sub-group analysis based on PAH (<155 cm and 155 cm and equal to TH), there was no difference in average AH between the groups. The quality of evidence according to the Grading of Recommendations Assessment, Development and Evaluation approach was low. Conclusion We found no evidence from controlled experimental and observational studies that compared with no treatment, the use of GnRH analogs improved AH in girls with EP.

Retention properties of the fluorinated bonded phase on liquid chromatography of aromatic hydrocarbons

The unique characteristics of a bonded-fluoroalkylsilane column, Fluofix, are described by comparison with those of a bonded octylsilane column, C8, in the reversed-phase chromatography of aromatic hydrocarbons. The selectivity of homologous aromatics on the fluorinated column varied with the methanol concentration in the eluent. At a larger proportion of methanol than 80:20 (v/v) the larger aromatics eluted faster than the smaller ones. However, with less methanol, the aromatics were eluted in order of their molecular size, as usually reported for a conventional hydrocarbonaceous column. A dependence of the retention mechanism on the composition of the eluent was suggested by the decrease in the entropy-enthalpy compensation temperature, beta, with increase of methanol concentration in the eluent. In order to explain the concentration dependence of the retention, the molecular interaction energy in the retention process was calculated by computer simulation. The interaction energy between aromatics and the stationary ligand on the Fluofix column was smaller than that on the C8 column and comparable to the interaction energy between the aromatics and methanol. At higher methanol concentrations, solute-fluorinated ligand complex formation was obstructed by the methanol molecules solvating the solute, reducing the retention of the larger aromatics.