Identification of two additives, locust bean gum (E-410) and guar gum (E-412), in food products by DNA-based methods.

Locust bean gum (E-410) and guar gum (E-412) are high molecular weight galactomannans used by the food industry as versatile food additives. The compounds, although chemically closely related, do not have the same functional properties when used in foods, and the substitution or unadvertised addition of either could change the desired qualities of the product. Analytical discrimination between E-410 and E-412 is technically difficult since they only differ in their galactose: mannose ratios, being 1 : 4 and 1 : 2 for locust bean gum and guar gum, respectively. A qualitative DNA-based method is reported for the authentication of additives E-410 and E-412 in finished food products (ice cream, dehydrated desserts, milk derivatives, dehydrated soups, salad dressing, marmalade and meat) from small quantities of food. DNA sequences from the nuclear ribosomal spacers of Ceratonia siliqua and Cyamopsis tetragonoloba, the plant sources of E-410 and E-412, respectively, were used to design polymerase chain reaction primers specific for each additive (PA23/PA21 and PG22/PG21). Twenty-two foods were analysed for the presence of E-410 and E-412 additives by this single-step polymerase chain reaction-based method. Positive DNA amplifications with the E-410 and/or E-412 primers were obtained in all 19 samples reported to contain either additive.

[Chest X-ray plate in bed-ridden patients in the Intensive Care Unit]. / La placa de tórax en pacientes encamados en la unidad de cuidados intensivos.

Chest radiographs using portable equipment is one most frequently used radiological investigations for bed-ridden patients. As the investigation is carried out using ionising radiation, the protection measures to be applied should be known. These investigations are normally hindered by the patient's condition and it is important to take into account that this circumstance can cause differences in the radiological study. As in all radiological studies, the reading and the diagnosis should be systematic and it is necessary to recognise the different elements that these patients may bare, in addition to the symptomatology of the possible pathologies that may exist in the chest.