Aminoguanidine ameliorates ovariectomy-induced neuronal deficits in rats by inhibiting AGE-mediated Aß production.

Advanced glycation end products (AGEs) have been reported to cause neurodegeneration, senile plaque formation and spatial learning and memory deficits. There is much evidence describing the beneficial effects of aminoguanidine (AG) on the central nervous system; AG is able to inhibit the receptor for AGEs and beta-amyloid (Aß) deposition in the brain, thus preventing cognitive decline and neurodegeneration. In this study, we investigated whether AG protects against ovariectomy-induced neuronal deficits and Aß deposition in rats. Animals in the ovariectomy group (OVX) group, and those in the OVX+AG group were treated with AG (100 mg/kg/day) for 8 weeks. Learning and memory were evaluated using the electric Y maze. AGE and Aß1-40 biochemical assessments were performed using enzyme-linked immunosorbent assay (ELISA) kits. Furthermore, evaluations of brain amyloid precursor protein 695 (APP695) mRNA expression by RT-PCR and AGE expression by immunohistochemistry were carried out. Ovariectomized rats exhibited memory impairment and Aß production disorder with upregulated APP695 mRNA and AGE expression levels. AG pretreatment relieved the ovariectomy-induced learning and memory disorder and significantly ameliorated the Aß production disturbance and AGE generation. Additionally, pathological changes in morphology were also significantly recovered. Our data reveal that AG plays a potentially neuroprotective role against ovariectomy-induced learning and cognitive impairment and Aß production disorder.Advanced glycation end products (AGEs) have been reported to cause neurodegeneration, senile plaque formation and spatial learning and memory deficits. There is much evidence describing the beneficial effects of aminoguanidine (AG) on the central nervous system; AG is able to inhibit the receptor for AGEs and beta-amyloid (Aß) deposition in the brain, thus preventing cognitive decline and neurodegeneration. In this study, we investigated whether AG protects against ovariectomy-induced neuronal deficits and Aß deposition in rats. Animals in the ovariectomy group (OVX) group, and those in the OVX+AG group were treated with AG (100 mg/kg/day) for 8 weeks. Learning and memory were evaluated using the electric Y maze. AGE and Aß1-40 biochemical assessments were performed using enzyme-linked immunosorbent assay (ELISA) kits. Furthermore, evaluations of brain amyloid precursor protein 695 (APP695) mRNA expression by RT-PCR and AGE expression by immunohistochemistry were carried out. Ovariectomized rats exhibited memory impairment and Aß production disorder with upregulated APP695 mRNA and AGE expression levels. AG pretreatment relieved the ovariectomy-induced learning and memory disorder and significantly ameliorated the Aß production disturbance and AGE generation. Additionally, pathological changes in morphology were also significantly recovered. Our data reveal that AG plays a potentially neuroprotective role against ovariectomy-induced learning and cognitive impairment and Aß production disorder.

Brazing Coupling Performance of Piezoelectric Waveguide Transducers for the Monitoring of High Temperature Components.

Piezoelectric waveguide transducers possess great potential for the online monitoring of high temperature critical components, in order to improve their operational safety. Due to the use of a waveguide bar, the sensory device is not susceptible to high temperature environments, which enables the long-term service of the piezoelectric transducers. However, the coupling between the waveguide bar and the high-temperature component has been proven to be the most important part of the monitoring system. In order to effectively transmit waves through the junction of the waveguide bar and the monitoring target, it is necessary to research a reliable coupling method to connect the waveguide transducers with the host structure. In the present research, the feasibility of brazing coupling for wave propagation through the junction was investigated through experiments. Piezoelectric waveguide transducers were welded using various kinds of brazing filler metals. The experimental results indicate that the coupling effects of the brazing welding depend on the filler metals. At the same time, some filler metals for the effective coupling of the transducer and the target monitoring component were identified. The brazing coupling method was verified that it can non-dispersively and effectively propagate waves into the host structure with much better reliability than the conventional dry coupling approach. Moreover, the high-temperature experimental results show that the brazing-coupled waveguide bar system can work reliably and stably in high temperatures at 300 °C for a long time. This work strives to pave a solid foundation for the application of piezoelectric waveguide transducers for the structural health monitoring of high temperature critical components.

Hypogastric artery autograft treating hemorrhage with infection of external iliac artery secondary to renal transplantation.

Massive hemorrhage from infected anastomosed site between the graft artery and the external iliac artery is one of the most serious complications of renal transplantation. Clinically, it is a rare but fatal occasion. We reported here one case of hemorrhage with infection in the iliac artery anastomosed site treated successfully with hypogastric artery autograft interposition in March 2003.

[RDP1258 on proliferation of rat splenocytes in vivo].

AIM: To explore the immunosuppressive effects of a novel HLA-derived peptide, RDP1258, on rat splenocyte proliferation in vivo and its underlying mechanisms. METHODS: RDP1258 was synthesized through artificial solid-phase synthesis method. Its effects on proliferative reaction of rat splenocytes in vivo were observed by (3)H-TDR incorporation method. And its effects on the heme oxygenase(HO) enzyme activity were analyzed by enzyme chemistry method. RESULTS: The results showed that the synthetic HLA-derived peptide RDP1258 obviously inhibited the proliferation of rat splenocytes stimulated by isoantigen and mitogen. In vivo administration of RDP1258 peptide to rats resulted in upregulation of splenic HO activity and rapid upregulation of HO-1 protein expression. CONCLUSION: HO-1 might participate in RDP1258 inhibiting the proliferation of rat splenocytes induced by mitogen and isoantigen in vivo.

Arterial anastomosis without sutures using ring pin stapler for clinical renal transplantation: comparison with suture anastomosis.

PURPOSE: The metal ring pin stapler was initially developed for microvascular surgery and there has been little experience of their use in larger vessels. We determined if the titanium ring pin coupling system could be safely and rapidly applied for arterial reconstruction in clinical renal transplantation. MATERIALS AND METHODS: The donor renal artery was end-to-end anastomosed to the internal iliac artery with titanium ring pin staplers in 36 patients. Anastomotic, clamp and total operative time and vascular problems were compared with those in the control group of sutured anastomosis in 39 transplant recipients. RESULTS: The completion of mechanical anastomosis required half the time of suture anastomosis. Mean clamp time was 17.8 minutes in the nonsuture group and 28.1 minutes in the control group. There was no significant difference in total operative time between the 2 groups. A small anastomotic line leak was noted in each group, which was temporary and self-limited. There were no postoperative anastomotic failures, postoperative bleeding episodes or need to revise the anastomosis (100% patency rate) in the 2 groups. Of the patients 61 were followed for 2 to 5 years. Transplant renal artery stenosis was observed in 1 patient in the nonsuture group but 3 in the control group. CONCLUSIONS: The anastomotic technique with the ring pin system is safe and simple, permitting an expeditious and everting anastomosis with a smooth intima-to-intima junction. Application of this technique may decrease warm ischemia time and the incidence of anastomotic artery stenosis, thus, improving outcomes.

[Inhibitory effects of HLA-derived peptide RDP1258 on proliferation and heme oxygenase-1 activity of rat splenocytes].

AIM: To observe the immunosuppression effect of a novel HLA-derived peptide RDP1258, and to explore its mechanisms. METHODS: RDP1258 was synthesized chemically. The effect of the peptide on alloreactive proliferation of rat splenocytes was observed by (3)H-TdR incorporation method. The heme oxygenase-1(HO-1) activity was analyzed by the enzyme assay. RESULTS: The results showed that the synthetic HLA-derived peptide could obviously inhibit the proliferation of rat splenocytes and HO-1 activity in a dose-dependent manner in-vitro. CONCLUSION: HO-1 may participate in the inhibitory effect of RDP1258 on the proliferation of rat splenocytes induced by mitogen or alloantigen.