Intranasal insulin treatment improves memory and learning in a rat amyloid-beta model of Alzheimer's disease

Recently, insulin has been used as a pro-cognitive agent for the potential treatment of Alzheimer's disease (AD), because of its ability to cross the brain-blood barrier (BBB) by a saturable transport system. This study has been designed to evaluate the effects of intranasal insulin regimen, as a bypass system of BBB, on spatial memory in amyloid-beta (Aβ) model of AD in rat. Unilateral infusion of Aβ_25-35 (10 nmol/2 µl/rat) into the lateral ventricular region of brain was used to produce a rat model of AD. After a 24-h recovery period, rats received insulin or vehicle via intraperitoneal or intranasal route (0.1, 0.2, and 0.3 IU) for 14 days. Memory function in rats was assessed by Morris water maze test, with 5 days of training and consequent probe test protocol. Different doses of intraperitoneal insulin did not have a significant effect on learning and memory in AD rats. However, intranasal insulin at doses of 0.2 and 0.3 IU improved the learning and memory in Aβ-received rats. In conclusion, intranasal insulin as a non-invasive strategy improves spatial learning and memory in AD model.

Effects of extremely low frequency electromagnetic fields on paraoxonase serum activity and lipid peroxidation metabolites in rat

BACKGROUND

Atherogenic effects of ELF-MF exposure have not been studied well so far. Therefore we have hypothesized that ELF-MF exposure might have atherogenic effect by impairing antioxidant function and increasing lipid peroxidation. This study was therefore undertaken to examine the effects of ELF-MF on paraoxonase (PON) activity, antioxidant capacity and lipid peroxidation metabolites. Effects of time on remodeling of antioxidant system were also investigated in this study.

METHODS

Seventy five Wistar rats were randomly allocated into five groups as follows: 1) Sham exposure, 2) Single exposure to 60 Hz, sacrificed immediately after exposure, 3) Single exposure to 60 Hz, sacrificed 72 hours after exposure, 4) Fourteen days of exposure to 60 Hz, sacrificed immediately after exposure, and 5) Fourteen days of exposure to 60 Hz, sacrificed 72 hours after exposure. Blood samples were collected and analyzed. The results were compared using ANOVA and post hoc Tukey HSD for multiple caparisons.

RESULTS

Single ELF-MF exposure significantly increased lipid peroxidation (CD and MDA) and increased antioxidant serum activity (HDL, paraoxonase activity, and serum total antioxidant capacity). Chronic ELF-MF exposure increased lipid peroxidation and affected antioxidant system. Free fatty acids levels were significantly increased after both single and two weeks exposure. Chronic exposure led to irreversible changes while acute exposure tended to reversible alterations on above mentioned parameters.

CONCLUSIONS

According to the results of this study, ELF-MF exposure could impair oxidant-antioxidant function and might increase oxidative stress and lipid peroxidation. Antioxidant capability was dependent on the duration and continuity of ELF-MF exposure.

Acceleration of skin wound healing with tragacanth (Astragalus) preparation: an experimental pilot study in rats

Gum tragacanth is a natural complex mixture of polysaccharides and alkaline minerals extracted from species of Astragalus plant, which is found widely in arid regions of the Middle East. In a pilot experimental study we examined the effects of its topical application on wound healing in ten albino adult male rats. Two similar parasagittal elliptical full-thickness wounds (control vs. test samples) were created on the dorsum of each animal. Test group samples were fully covered by a thin layer of gum tragacanth daily. The extent of wound healing was evaluated by planimetric analysis on multiple occasions during the 10-day study period. On the 7th day of the study, the percent of wound closure was significantly higher in gum tragacanth-treated specimens compared to the control samples (87%±2% vs. 70%±4%, P<0.001). The majority of wounds in the test group were completely closed by the 10th day of the study. The difference in wound healing index measured by histological examination on day 10 of the study was also statistically meaningful between the two groups (0.624±0.097 vs. 0.255±0.063, P<0.05). The results of this study clearly showed the useful effects of topical application of gum tragacanth in acceleration of skin wound contraction and healing. More studies are encouraged to identify the implicating agents and precisely understand the mechanism by which they exert their wound healing effects.

Endonasal laser-assisted microscopic dacryocystorhinostomy: surgical technique and follow-up results

PURPOSE

Endonasal dacryocystorhinostomy is known as an increasingly attractive and effective approach for the surgical treatment of nasal duct obstruction with minimal complications and best cosmetic consequences. In a relatively large-scale case-series study over a 5-year period, we describe the surgical technique and 12-month follow-up results of microscopic laser dacryocystorhinostomy with particular regard to the effect of various pre-/postoperational factors (ie, patients' sex, age, symptoms chronicity, previous interventions, duration of silicone intubation) on the surgical outcome.

MATERIALS AND METHODS

A total of 162 cases in 151 patients with chronic epiphora, mucocele, or recurrent episodes of dacryocystitis were included in the study. Endonasal laser dacryocystorhinostomy was performed using a surgical microscope with transcanalicular lacrimal sac illumination. The laser types used were potassium-titanyl-phosphate and neodymium:yttrium-aluminum-garnet for ablation of nasal mucosa and application to bone, respectively. Patients were evaluated 6 months and 1 year later. Data were analyzed by chi(2) tests.

RESULTS

There were no major complications during or after the operations. Complete cure occurred in 89.5% (after 6 months) and 74.2% (after 1 year) of the cases. Anatomical patency was shown by lacrimal system irrigation with fluorescein in 81.5% of the cases after the 12-month follow-up. It was found that patients younger than 55 years, with symptoms lasting less than 1 year, and without history of nasal problems, had significantly higher surgical success rates (P < .05). Moreover, rates of failure were significantly lower in cases whose canaliculi were intubated for 5 to 6 months (P < .05).

CONCLUSIONS

Endonasal microscopic laser dacryocystorhinostomy is a safe and minimally invasive procedure with reasonable results. It has many advantages over external or other conventional approaches. Successful results could be further enhanced by more wisely selecting the patients and by silicone extubation after 6 months.