Pre- and post-estrogen administration in global cerebral ischemia reduces blood-brain barrier breakdown in ovariectomized rats

The aim of present study was to determine the effect of estrogen treatment on blood-brain barrier permeability in rats with induced global cerebral ischemia. The study included six-month-old female Sprague-Dawley rats which were divided into the following groups: Control-Ischemia-Reperfusion (C + I-R); Ovariectomy-Ischemia-Reperfusion (Ovx + I-R); Ovariectomy + Estrogen + Ischemia-Reperfusion (Ovx + E + I-R); Ovariectomy + Ischemia-Reperfusion + Estrogen (Ovx + I-R + E). Ischemia-reperfusion was induced by clamping two carotid arteries, then opening the clamp. Blood-brain barrier permeability was visualized by Evans Blue extravasation and quantified by spectrophotometry. Our results indicate that following ischemia-reperfusion the BBB permeability is increased in ovariectomized rats (Evans Blue extravasation) compared to the control group in the cortex, thalamus, hippocampus, cerebellum and brain stem, while in the midbrain no significant increase was detected. In contrast, BBB permeability in the groups treated with estrogen, administered either before or after ischemia-reperfusion, was significantly lower than in ovariectomized animals. In conclusion, the increase in BBB permeability resulting from experimentally induced cerebral ischemia was prevented by exogenous estrogen treatment. The study results indicate that estrogen may be used for therapeutic purposes in ischemia-reperfusion

JOURNAL OF PSYCHIATRIC NURSING

Objectives: This study aims to examine the effects of psychoeducation on problem solving skills of cancer patients. Methods: This study was conducted as a quasi-experimental research with pre- and post-test design. This study was performed in Manisa at a radiation oncology service between April and December 2016. The study sample consisted of 32 patients who met the study inclusion criteria. The patients were interviewed and provided with psychoeducation individually for 1 hour per week in a period of 6 weeks. The data were collected using an Introductory Information Form and the Problem Solving Inventory (PSI). The data was evaluated using number, percent distribution and paired samples t test. Results: The patients' PSI (total) pre- and post-test mean scores were 112. 75 +/- 26.68 and 63.28 +/- 12.67, respectively. The difference between the patients' PSI (total) pre-and post-test mean scores was found to be statistically significant (t=13.173, p<0.001). The differences between patients' pre-and post-test mean scores on the PSI subscales were also found to be statistically significant (p<0.001). Conclusion: The present study results showed that psychoeducation positively changed the perception of problem-solving in cancer patients

The effect of nicotine pretreatment on the blood-brain barrier permeability in nicotine-induced seizures

Nicotine is a toxic substance which because of its lipid solubility can cross the blood brain barrier. It has several different actions in the CNS; one of which is neuroexcitation, where it can result in seizure activity. Based on the observations that nicotine pretreatment ameliorated blood flow and glucose utilisation in caudate putamen on rats whose mesostriatal dopamine system had been cut and that nicotine pretreatment rendered animals less susceptible to nicotine induced seizures than saline administered controls, we conducted this set of experiments where we investigated the protective effect of nicotine pretreatment on the BBB permeability in nicotine induced seizures. Administration of saline or subseizure producing dose of nicotine (1 mg/kg i.p.) was followed by seizure producing doses of nicotine (2, 5 or 8 mg/kg, i. p.). Intravenous technique was used to calculate the unidirectional blood to brain transfer constant (Kin) for six different brain regions, with [H-3] alpha-AIB as a tracer. Mean Kin in brains of all acute nicotine groups (2, 5 or 8 mg/kg) increased by 83.94%, 182.6% and 265% respectively. Twenty one days chronic nicotine pretreatment prevented the rise in Kin AIB to 2 mg/kg acute nicotine and partially ameliorated the disturbed BBB to 5 and 8 mg/kg

Tolerance to pentylentetrazol-induced convulsions and protection of cerebrovascular integrity by chronic nicotine

The authors' previous studies have shown that in nicotine-induced seizures sensitivity was decreased and blood-brain barrier (BBB) disruption was prevented as a consequence of nicotine pretreatment. This study aimed to investigate the possible protective actions of nicotine on cerebrovascular permeability and seizures induced by pentylentetrazol (PTZ) injection. Cerebrovascular effects of nicotine were evaluated by measuring the permeability changes of BBB using Evans-Blue (EB) dye and specific gravity (SG), which indicates brain water and protein content. The experiments were carried out on Wistar rats. Animals were randomly divided into two groups. Convulsions were induced by injection of PTZ (80 mg/kg i.v.) in rats either pretreated with nicotine daily with a low dose of 0.8 mg/kg day.for 21 days or injected with a single dose of 6 mg/kg mecamylamine. The same procedures were followed in control rats with the exception that they were injected only with saline. PTZ injection caused tonic-clonic convulsions and increased the EB dye leakage and specific gravity values in saline-injected control rat brains. Daily injection of nicotine lessened the intensity of seizures. These were accompanied by marked decreases in both the leakage of EB and brain water content. Acute administration of a nAChR antagonist mecamylamine significantly increased seizure latency and decreased the duration of seizures. Thereby, mecamylamine reduced the EB leakage and water content in most brain regions. These results indicate that development of tolerance to PTZ convulsions can be produced by chronic nicotine administration in rats. The mechanism for this effect currently needs clarification. Moreover, the data also suggest that cholinergic activity may account for occurrence of PTZ-induced convulsions

CHANGES IN THE PERMEABILITY OF THE BLOOD - BRAIN BARRIER IN ACUTE HYPERAMMONEMIA - EFFECT OF DEXAMETHASONE

This study was designed to determine the contribution of elevated plasma ammonia levels to blood-brain barrier (BBB) abnormalities in the presence of intact liver. The permeability changes of the BBB were investigated grossly with Evans blue (EB) and quantitatively by measuring the blood-to-brain transfer content for alpha-aminoisobutyric acid (AIB) in normal rats and rats subjected to sublethal doses of ammonium acetate (NH4OAc) (750 and 600 mg/kg ip; at 30-min intervals). Some rats were pretreated with dexamethasone (DXN). Injection of NH4OAc increased both plasma and brain ammonia concentrations about 16-and 5-fold, respectively, above the control level. In rats receiving NH4OAc injection, the blood-to-brain transfer constant (K(i)) for AIB was increased 3- to 11-fold. The elevated K(i) values were limited to certain gray matter areas and less pronounced permeability changes were detected in white matter. Extravasation sites of EB were more restricted and were especially observed in thalamus and cerebellum, whereas cortex and white matter were unaffected. Dexamethasone pretreatment for 3 d reduced both leakage of EB and the K(i) for AIB in NH4OAc injected animals, whereas acute treatment appeared ineffective. Dexamethasone did not prevent the development of coma but slightly decreased the ammonia concentration in plasma and brain. The results obtained indicate that hyperammonemia may disrupt BBB integrity not only to AIB and EB but also enhance the transport of other solutes

Protective effect of magnesium supplementation on experimental 3-methyl cholantrene-induced fibrosarcoma and changes in tissue magnesium distribution during carcinogenesis in rats

In this study, we wanted to examine the effect of magnesium (Mg2+) supplementation on the experimental 3-methyl cholantrene (3-MC)-induced fibrosarcoma and alterations in (Mg2+) distribution in several tissues of the rats, during carcinogenesis. It was determined that serum and tissue (Mg2+) levels of the rats in (Mg2+)-supplemented diet group were higher than those of the rats in the (Mg2+)-nonsupplemented and control groups. The mean time of fibrosarcoma development for (Mg2+)-supplemented group was longer than (Mg2+)-nonsupplemented group (p < 0.05). Symptoms of hypermagnesemia were not observed in any of the rats. These results suggests that dietary (Mg2+) supplementation may have a partial anticarcinogenic effect on experimental 3-MC-induced fibrosarcoma by prolongation of the latent period of carcinogenesis