Structural changes in the rat placenta during the last third of gestation discovered by stereology.

Structural changes in the rat placenta during the last third of gestation were for the first time assessed by stereology. Fischer female rats were euthanized on the day 16 or day 19 of gestation, and 35 placentas were collected. Three randomly selected placentas from each group were stereologically analyzed for the absolute volume. The proportion of the glycogenic cells and the trophoblast giant cells (TGC) in the basal part of the placenta was calculated using volume density. The absolute volume of the rat placenta on the day 16 of gestation was determined as 0.0638 cm3. The labyrinth comprised 0.0274 cm3, the basal plate 0.0271 cm3 and the decidua 0.0093 cm3. On the day 19 of gestation, the absolute volume of the placenta was 0.1627 cm3, the labyrinth occupied 0.0922 cm3, the basal plate 0.0596 cm3 and the decidua 0.0109 cm3. The volume density of trophoblast giant cells was 0.174 cm0 on the day 16 and 0.107 cm0 on the day 19 of gestation. The glycogenic cells comprised 0.379 percentage of the basal plate on the day 16 and 0.236 on the day 19 of gestation. We conclude that the absolute volume of the whole placenta and the labyrinth has increased from day 16 to the day 19 of gestation. In contrast, the volume density of glycogenic cells and trophoblast giant cells was higher on the day 16 than on the day 19 of gestation, probably due to the intensive trophoblast invasion during that time.

Increased permeability of the blood-brain barrier following administration of glyceryl trinitrate in common carp (Cyprinus carpio L.).

Nitric oxide (NO) has been implicated in the pathogenesis of migraine and treatment with its exogenous donor glyceryl trinitrate (GTN) represents widely accepted experimental "migraine model". In this study, glyceryl trinitrate was administered intraperitoneally to carps, serum nitrite and nitrate levels were determined, permeability of blood-brain barrier was investigated, and histological changes of brain tissue were analyzed. Serum nitrite and nitrate levels displayed characteristic biphasic pattern with moderate initial increase and maximal terminal increase, suggesting the GTN-induced endogenous NO synthesis. Increased permeability of the blood-brain barrier in GTN-treated animals was determined based on Evans blue capillary leakage into the brain tissue. Histological analysis revealed changes consistent with vasodilatation and oedema. Our study strongly supports the importance of the NO role in the pathogenesis of migraine attacks and increase in blood-brain barrier permeability during the attack. The study has also provided evidence that this mechanism of action is conserved to the lower vertebrate.

Haematology and some blood chemical parameters of young carp till the age of three years.

Haematological and biochemical analyses of blood were performed in carp (Cyprinus carpio L.) kept in small ponds. Caught and anaesthetised carp were clinically examined and blood samples were taken at regular intervals during the three years. In the first year of examinations, the haemoglobin and haematocrit values of carp fry significantly increased (P < 0.01) from June to September. The intensive growth of carp in the summer period in the second year was accompanied by adequate erythropoiesis. During hibernation haematocrit and haemoglobin significantly decreased (P < 0.05) and mean corpuscular haemoglobin concentration (MCHC) increased (P < 0.01) in both scaly and mirror carp. MCHC increased also with the age and increasing body weight of the fish. Mirror carp had lower haematocrit and haemoglobin values than scaly carp (P < 0.01). Comparative haematological analyses between carp of normal and poor body condition showed that moderate anaemia appeared in those with poor body condition. The results indicate that there is marked seasonal and age-dependent variation in the values of haematocrit and haemoglobin. Pond water quality investigations indicated good environmental conditions. A 50% increase (P < 0.05) of glucose concentration was found from June to September in the blood plasma of carp in the third year, accompanied by an even more increased (80%; P < 0.01) concentration of total lipids. At the same time, considerable changes of cholesterol and total protein concentrations were not observed. The results suggest that the investigated haematological and biochemical variables could be successfully utilised in monitoring the metabolic balance and health status of fish in intensive culture.