Vitamin D deficiency in children and adolescents with food allergy: Association with number of allergens, sun exposure and nutritional status

Our objective was to describe the serum vitamin D concentrations of children and adolescents with food allergy (FA) and to verify the association between the number of food allergens involved, length of sun exposure, and nutritional status. Through a cross-sectional study, 79 patients with FA, from ages 2 to 15 years, were assessed and followed up in a reference outpatient clinic, in Sao Paulo, Brazil. Clinical and biochemical data were collected for analysis of 25(OH)D, calcium, phosphorus, phosphatase, parathyroid hormone (PTH), and high-sensitivity C-reactive protein (hs-CRP). The cut-off point used for vitamin D deficiency was 25(OH)D ≤ 20 ng/mL. Vitamin D deficiency was detected in 45.6% of patients with a median age of 6.9 years (Interquartile range [IQR] 4.7; 10.2). The median serum 25(OH)D concentration was 21.1 ng/mL (IQR 17.8; 26.0). Multivariate linear regression was performed considering serum vitamin D level as a dependent variable. Allergy to multiple foods (inverse) and length of sun exposure (direct), but not nutritional status, were independently associated with serum 25(OH)D levels (P = 0.034 and P = 0.014, respectively). Patients with cow’s milk allergy also showed lower vitamin D concentrations in comparison with other FA (19.1 ng/mL [IQR 16.6; 24.4] vs 22.2 ng/mL [IQR 18.1; 27.1] [P = 0.056]). Vitamin D deficiency affected about half of individuals with FA. Multiple food allergy was associated with lower vitamin D concentrations, reinforcing the importance of monitoring vitamin D status in patients with FA (AU)

Seasonal variation of the chemical constituents from Croton species.

The terpenes, sterols, alkaloid (glaucine) and alpha-tocopherol show seasonal variation for Croton hemiargyreus hemiargyreus and Croton echinocarpus. The amounts of triterpenes are higher during the tropical summer and in most samples the major sesquiterpene was characterized as caryophyllene. The seasonal variation of glaucine showed a maximum between June and October for C. hemiargyreus, and was present only in January and June in C. echinocarpus.

Performance of capillary columns for high-temperature gas chromatography

The developments in stationary-phase synthesis and capillary column technology have opened new perspectives in the analysis of high-molecular-weight compounds (600 daltons) and thermolabile organic compounds by high-temperature-high-resolution gas chromatography. This branch of high-resolution gas chromatography deals with analysis performed up to 390 degrees C oven temperature (with some applications going up to 420 degrees C and even a few applications to 450 degrees C maximum). The technique has been applied to many different fields of science (e.g., organic geochemistry, environmental chemistry, archeology, and natural product research). Apolar and medium-polar gum phases can now be operated at temperatures from 400 to 480 degrees C, but these higher temperatures are seldom used because of the thermostability of the material used to make the capillary tubing. This paper shows the performance of nine commercial high-temperature columns when used in routine applications.

Rapid screening of natural products by high-resolution high-temperature gas chromatography.

The crude ethanol extracts from the leaves of three Croton hemiargyrus hemiargyreus plants are fractionated by thin-layer chromatography, yielding five fractions. The fractions and the crude extract are analyzed by high-temperature high-resolution gas chromatography coupled with mass spectrometry (HT-HRGC-MS). Several natural products, including thermolabile components, can be characterized directly in the samples, such as alkaloids, terpenes, flavonoids, acids, alcohols, etc. The cold on-column technique proves to be appropriate for the injection of these thermolabile compounds. HT-HRGC-MS is shown to be a valuable tool and an alternative technique to classical phytochemical procedures for the simple and fast routine analysis of natural products in crude extracts.