Species with environmental sex determination may show sex ratios that differ from 1:1; therefore, sex ratio is an important variable when studying the population dynamics of these species. For instance, when estimating population size and productivity, sex ratio would be a required parameter. For endangered species, such as sea turtles, this is particularly important in order to understand the possible effects of human impacts and conservation measures. Unfortunately, only adult sea turtles show evident external sexual dimorphism; sex ratios are more difficult to obtain for the juvenile class, which represents the largest part of a population. Here we present the first extensive assessment of the sex ratio of juvenile loggerhead turtles Caretta caretta in the Mediterranean Sea. A total of 310 dead turtles from 4 different areas were sexed by direct examination of gonads, the most reliable sexing method. Females comprised 54.2% of the whole sample, and no significant differences were observed among study areas. However, this value cannot be ascribed to a single population, because specimens from different nesting sites - both within and outside the Mediterranean - share the same foraging areas, and each population may potentially contribute a different sex ratio. Although we recorded an unbiased sex ratio, our results were compatible with a hypothetical scenario in which Mediterranean nesting beaches produce a majority of females when other information from the region (distribution, mixed stocks and sex ratios) was considered. © Inter-Research 2006

Seasonal changes of testicular activity of the swordfish Xiphias gladius and correlations of plasma levels of testosterone (T) and 11‐ketotestosterone (11‐KT) with proliferation and apoptosis of germ cells, determined, respectively, with monoclonal antibodies against proliferating cell nuclear antigen and terminal deoxynucleotidyl transferase‐mediated d’UTP nick end labelling, are described. Three phases of the reproductive cycle were found: active spermatogenic (May), spawning (June to July) and spent (August to September) stages. Germ cell proliferating activity was highest in May, decreased during June to July and remained stable during August to September. Apoptotic germ cells, primary spermatocytes and spermatogonia, were present in all the specimens analysed and were more abundant in May. The levels of 11‐KT in plasma were always higher than T and were highest in May, in concomitance with the maximum proliferation and apoptosis rate of germ cells.

Published data strongly suggest that tumor progression and malignancy are associated with increased angiogenesis. However, no data have been published concerning the relationship between microvascular density (MVD), tumor cytosol, and blood vascular endothelial growth factor (VEGF) concentrations in canine non-Hodgkin lymphoma (C-NHL), a neoplasm that shares biological and clinical characteristics with human NHL. We have evaluated MVD and tumor cytosol, serum (S), platelet-poor plasma (P-PP), plasma-activated platelet rich (P-APR) VEGF concentration in a series of 63 B-cells C-NHL by means of immunohistochemistry and enzyme-linked immuno-sorbent assay (ELISA) detection of VEGF. We found that MVD, VEGF from cytosol, and VEGF from P-APR are significantly correlated (p ranging from 0.001 to 0.003) and that these parameters paralleled with the malignancy degree of NHL. Accordingly, spontaneous C-NHL seems to be an interesting model to study the role of angiogenesis as interspecies pathway of tumor malignancy and we suggest that VEGF from P-APR might be a novel useful circulating bio-marker of tumor angiogenesis.