Facultative nest-parasitism among Iberian shrubsteppe passerines

This paper analyses intra- and interspecific facultative nest parasitism of shrubsteppe passerines on the Iberian peninsula through 4 seasons, from 1991–94. Daily frequency of nest parasitism was very low (f = 3.9 × 10^-3 during laying and f = 2.8 × 10^-4 during incubation). Observation of the 3 examples found in the field of 2 intraspecific and one interspecific instances revealed that the eggs were accepted and, in the latter case, that the parasitic chick was viable. The experimental tests in the field of placing 1 additional egg that was similar to (n = 57) or clearly different from the host (n = 50), in order to simulate both intra and interspecific parasitism revealed: (i) higher rejection rates in areas with higher risk of predation and (ii) similar rejection rates for both types of eggs. The experimental addition of nestlings of other species (n = 6) revealed that in 67% of the cases studied, the parasitic chick had a normal growth rate. It is suggested that nest parasitism among these species is an occasional behaviour pattern, caused by high nest predation rates in Iberian shrubsteppe habitats.     

Comparison between in vitro potency tests for Cuban hepatitis B vaccine: contribution to the standardization process.

Quality control of recombinant Hepatitis B vaccines performed by National Control Laboratories prior to marketing vaccine batches requires in vivo and or a well validated in vitro potency assays as recommended by WHO technical series. The in vitro test must also demonstrate its suitability for monitoring the consistency of the vaccine manufacturer. The aim of this study was to establish the relationship between both in vitro potency tests performed by Cuban manufacturer and National Control Laboratory for Hepatitis B vaccine and the suitability of our method for monitoring the manufacturer's test results and consistency. We also intended to contribute to the standardisation process consisting of in vitro methods for this vaccine.     

Development of astroglial cells in the encephalon of Gallotia galloti: A Golgi technique study

Some variants of the Golgi techniques have been used to study the possible origin and developmental sequence of astroglial cells in the lizard Gallotia galloti. the developmental sequence consists of progressive transformations of astroglial cells originating either from radial glia or from glioblasts. The so-called displaced radial glia, an intermediate cellular type between radial glia and astrocytes, indicate the radial glia/astrocytes transformation. Apparently, glioblasts also evolve into astroblasts that, in turn could develop into immature protoplasmic or fibrous astrocytes, precursors of mature protoplasmic and fibrous astrocytes, respectively. The present study confirms our previous ultrastructural and immunohistochemical studies on the same animal. © 1995 Wiley-Liss, Inc.