Age-dependent changes in the medial prefrontal cortex and medial amygdala structure, and elevated plus-maze performance in the healthy male Wistar rats.

Aging affects different parts of the brain structure and function. These changes are associated with several age-related emotional alterations like anxiety that is regulated by the amygdala and medial prefrontal cortex (mPFC). Thus, this study aimed to explore the effects of aging on the morphology changes in these regions. Twenty male Wistar rats were assigned to young and old groups. The anxiety level was evaluated by elevated plus-maze. Then, their brains were removed, fixed, cut, and stained with Cresyl Violet or Golgi-Cox. In addition to the estimation of stereological parameters, dendrite complexity, and spatial distribution of the neurons in the mPFC and amygdala were evaluated. Aging increased the medial amygdala volume and its total number of neurons, but it did not have a significant effect on these parameters in the mPFC. Furthermore, the size of the neurons in the mPFC increased, whereas the total length of the dendrite and its complexity significantly decreased with aging in this structure and increased in the amygdala. Although aging did not significantly change the dendritic spine density in both regions, old rats showed a more mature spine in the mPFC and more anxiety-like behavior. In conclusion, the increase of anxiety in the old individuals could be attributed to structural changes in the morphology of the dendrite and neuron and its spatial distribution in the mPFC and amygdala. The findings of this study partly support this hypothesis.

Effect of intradermal injection of heparinase III on skin wound healing in diabetic rats.

AIM: neuropathy and vascular damage in this disease. Heparanase is an endoglycosidase that degrades heparan sulfate in the extracellular matrix and is believed to promote angiogenesis. The present study has been performed to investigate the effect of heparinase III (an enzyme which exclusively cleaves heparan sulfate) on wound healing in diabetic rats. METHODS: The rats became diabetic by a single streptozotocin injection. Two weeks later, a wound was created by excision of the skin in the left paravertebral area. Heparinase III (0.2 unit) was injected intradermally around the wound every 5 days, starting on day one, for a total of three doses. The wound area was measured every 3 days. After completion of wound healing, full thickness skin samples were taken from the wound sites and evaluated for volume density of the collagen bundles, numerical density of the fibroblasts, and length density of the vessels. RESULTS: Heparinase III accelerated wound closure compared to control diabetic animals. Microscopical examination revealed that it increased angiogenesis with no significant effect on collagen density and the number of fibroblasts. CONCLUSION: Heparinase III induces angiogenesis and improves wound healing in diabetic animal model.

The Effect of Intra-CA1 Agmatine Microinjection on Water Maze Learning and Memory in Rat.

BACKGROUND: Reports on agmatine are controversial showing that it may improve memory, it can deteriorate memory and some did not notice any interference with learning and memory. In the present study, the effect of directly intra-CA1 agmatine microinjection on water maze learning and memory has been assessed. METHODS: The cannuls were implanted in hippocampal CA1 regions of rats in a sterotaxic frame after general anesthesia. After one week recovery period, the animals were assessed in the reference memory version of water maze. Agmatine (1, 10, 100 or 200 µg/0.5 µl) or saline were infused 20 minutes before or immediately after training. RESULTS: Agmatine-treated rats did not show any significant difference neither in water maze acquisition nor in consolidation task in comparison with control and sham groups. CONCLUSION: Agmatine does not affect water maze learning and memory.

Administration of heparanase-III improves the survival and angiogenesis of rat skin autografts.

AIM: Heparanase, a glycohydrolase enzyme, cleaves heparan sulfate in the tissue matrix. Heparan sulfate degradation causes the release of angiogenic and growth factors, leading to angiogenesis. The aim of this paper was to evaluate the angiogenic effect of heparinase-III administration on skin autograft healing in rat. METHODS: Four groups of 14 adult male Charles River rats were enrolled. Full thickness skin autografts (15 mm in diameter) were made on the interscapular region of each rat. After 24 hours, 0.1 cc of heparanase, at the three concentrations of 0.1, 0.2, and 0.4 units, were injected intradermally into the grafts of each of the three case groups. The control group received an equal volume of the vehicle (buffered phosphate solution). After 5 days, biopsy specimens from skin grafts of 5 randomly selected rats of each group were submitted for histological studies. RESULTS: The concentration of vessels (with 5-50 mm in diameter) in the grafts of the groups receiving 0.2 and 0.4 units of heparanase-III was significantly more than that of the control group (100.43+/-11.24 and 95.85+/-12.44 vs 71.42+/-5.22 vessels/mm(2), P<0.05). The graft survival time of the group that received 0.2 U heparanase-III was significantly longer than that of the control group (15.43+/-0.72 vs 13.23+/-0.69 days; P<0.05). CONCLUSIONS: Heparanase-III administration improves the healing of rat skin autografts through induction of angiogenesis.

Narrowband DWDM filters based on Fibonacci-class quasi-periodic structures.

In this paper, we propose a narrowband DWDM filter structure, whose reflection band characteristics, meets the ITU-T standard. The proposed filter structure is based on Fibonacci quasi-periodic structures composed of multilayers with large index differences. Studying the effects of the optical and geometrical parameters of Fibonacci quasi-periodic structures on its filtering properties, we have realized that to achieve the ITU-T standard, we need to cascade two successive structures both with the same generation numbers j=4 and orders n=25 and apodized refractive indices. The apodization process helps to minimize the stop band sidelobes. We have also demonstrated that beside Fibonacci's order, n, the layers dimensions, and their refractive index ratios are the main design parameters.