Production optimization of 99Mo/99mTc zirconium molybate gel generators at semi-automatic device: DISIGEG.

DISIGEG is a synthesis installation of zirconium (99)Mo-molybdate gels for (99)Mo/(99m)Tc generator production, which has been designed, built and installed at the ININ. The device consists of a synthesis reactor and five systems controlled via keyboard: (1) raw material access, (2) chemical air stirring, (3) gel dried by air and infrared heating, (4) moisture removal and (5) gel extraction. DISIGEG operation is described and dried condition effects of zirconium (99)Mo- molybdate gels on (99)Mo/(99m)Tc generator performance were evaluated as well as some physical-chemical properties of these gels. The results reveal that temperature, time and air flow applied during the drying process directly affects zirconium (99)Mo-molybdate gel generator performance. All gels prepared have a similar chemical structure probably constituted by three-dimensional network, based on zirconium pentagonal bipyramids and molybdenum octahedral. Basic structural variations cause a change in gel porosity and permeability, favouring or inhibiting (99m)TcO(4)(-) diffusion into the matrix. The (99m)TcO(4)(-) eluates produced by (99)Mo/(99m)Tc zirconium (99)Mo-molybdate gel generators prepared in DISIGEG, air dried at 80°C for 5h and using an air flow of 90mm, satisfied all the Pharmacopoeias regulations: (99m)Tc yield between 70-75%, (99)Mo breakthrough less than 3×10(-3)%, radiochemical purities about 97% sterile and pyrogen-free eluates with a pH of 6.

Effects of the environmental light conditions on the ultrastructure of the harderian gland in the newborn rat. biochemical correlation with the pineal gland.

Morphological changes at the levels of both light and electron microscopy were studied regarding the secretory elements of the Harderian glands of neonatal rats, induced by environmental lighting conditions. The results were correlated with biochemical determinations of serotonin levels and hydroxyindole-O-methyl transferase (HIOMT) activity in the pineal gland. Neonatal male albino rats were divided into three groups: 12 were exposed to a light period for seven days; 12 to a dark period, and 12 to diurnal lighting conditions (light, 12 hours; darkness, 12 hours), as controls. In each group some animals were killed at 1.00 pm. The Harderian gland of each animal was immediately fixed and processed for light and electron microscopy while the pineal gland was homogenized in a fixative for biochemical determination of serotonin levels and HIOMT activity. On the light period the acinar lumen was observed to be dilated with increased secretions from the acini and excretory ducts while on the dark period the acinar lumen narrowed with hardly any secretions. On the dark period there were no changes in the cyclic variations of serotonin levels and HIOMT activity in the pineal gland; while on the light period, these cycles disappeared. It is concluded that secretory activity of the Harderian gland is modified by environmental lighting conditions, and that secretions produced by this gland appear to be directly related to the control mechanism of melatonin production by the pineal gland in neonatal rats.