Effect of intrahippocampal injection of aluminum on active avoidance learning in adult male rats.

Aim of this research was to study the effect of intrahippocampal injection of different doses of AlCl3 in adult male rats on active avoidance learning. Thirty five adult male Wistar rats (250-300 g) were used into five groups: (1) Control, (2) Test-I received daily 1 microL AlCl3 1%, pH = 7.2, 3); Test-II received daily 1 microL AlCl3 0.5%, pH = 3.4, 4); Sham-I received daily 1 microL aCSF, pH = 7.2, 5); Sham-II received daily 1 microL aCSF, pH = 3.4. All rats in test and sham groups treated 10 min before training. Animals were anaesthetized with ketamine HCl/xylazine (90/10 mg kg(-1) b.wt.(-1), i.p.) and underwent a stereotaxic surgery for implant of two stainless steel guide cannula into the hippocampus bilaterally. Every day 10 min after above treatments all rats were used to assess the spatial learning performing using Y-maze. Criterion Correct Response (CCR) was 90% in last session of training. There were no significant differences between training sessions to receiving CCR in control, Sham-I and Sham-II groups. Cognition in animals received AlCl3 1%, pH = 7.2 was impaired significantly with compare to other groups (*p<0.0001). Present results show that intrahippocampal injection of AlCl3 1%, causes active avoidance learning impairment significantly. The exact mechanism of Al3 effect on brain and cognition is remains unknown.

Alterations in osmotic fragility of the red blood cells in hypo- and hyperthyroid patients.

BACKGROUND: Changes in concentration of thyroid hormones can affect Na+-K+-ATPase number and activity and phospholipid composition of the cell membranes leading to changes in the surface to volume ratio and strength of membrane. AIM: In this study, the osmotic fragility of the red blood cells from non-treated hypo- and hyperthyroid patients was compared to that of control subjects. MATERIAL/SUBJECTS AND METHODS: After 3 washings with normal saline, red blood cells were placed in varying concentrations of sodium chloride (Na- Cl) (0-0.9%) and fragility was assessed with colorimetric method; to do this, after the incubation period, tubes were centrifuged and the optical density of the tubes was measured. Hemolysis percentage in tubes was calculated based on 100% hemolysis in the tubes containing no NaCl (0%). RESULTS: Osmotic fragility of the cells from hyperthyroid patients in 0.45% NaCl was significantly lower than control subjects (74.6%+/-30.2 vs 93.8%+/-9.1, p<0.01). The osmotic fragility of red blood cells in 0.5% concentration of sodium chloride in hyperthyroid patients was significantly lower compared to that of controls (27.8%+/-26.0 vs 63.5%+/-27.5, p<0.001). No significant difference was observed between the osmotic fragility of the hypothyroid patients compared with control subjects. CONCLUSIONS: Alteration in osmotic fragility is seen in patients with hyperthyroidism; however, anemia reported in hypo- or hyperthyroid patients is not due to high osmotic fragility of red blood cells and other causes need to be investigated.