Influence of contrast ultrasonography with perflutren lipid microspheres on microvessel injury.

Microbubbles have been reported to enhance ultrasound (US)-related side effects in animal systems. The present study investigated the influence of contrast ultrasonography (US) with perflutren lipid microspheres, a recently developed second-generation contrast agent, on microvessels. Rat mesentery was exposed to 1.8-MHz pulsed US with intravenous injection of perflutren (0.1 or 1.0 ml/kg) or Levovist (300 mg/kg), and the microvessel bleeding and endothelial cell injury was examined. Impaired endothelial cells were identified by the fluorescence of propidium iodide. Microvessel bleeding was examined also in the rat myocardium. The interaction between 0.1 ml/kg of perflutren and US exposure did not cause microvessel bleeding, and did not increase endothelial cell injury compared with the sham operation, unless frequent, strong US exposure occurred. When the dose was increased to 1.0 ml/kg, the combination of perflutren and US exposure resulted in capillary bleeding and increased endothelial cell injury in capillaries and venules (p<0.01). However, the incidence of microvessel bleeding and endothelial cell injury did not exceed that with Levovist microbubbles. In the myocardium, microvessel bleeding was not observed under any conditions. In conclusion, perflutren lipid microspheres enhanced US-related microvessel injury as with other contrast agents at the dose of 1.0 ml/kg, but not with 0.1 ml/kg and the appropriate US setting.     

Theoretical study on aromatic and open-shell characteristics of carbon nanobelts composed of indeno[1,2-b]fluorene units: dependence on the number of units and charge states

In this study, we theoretically investigate the aromatic and open-shell characteristics of carbon nanobelts (CNBs) composed of five- and six-membered rings. We have designed nanobelts composed of indeno[1,2-b]fluorene ([1,2-b]IF) units, which are referred to as [N]IF-CNB (N: the number of five-membered rings). The number of π-electrons, n_π, in neutral [N]IF-CNB is 7N, and thus depending on N and charge states, n_π can be 4n + 2 and 4n. Quantum chemical calculations on neutral [6]IF-CNB and [8]IF-CNB and dicationic [8]IF-CNB²⁺ have revealed that they are expected to exhibit unique aromatic and open-shell characteristics depending on n_π, there are several analogies of the electronic structures in [N]IF-CNB to those in [N]annulene. Delocalized and intermediate open-shell electronic structures of [N]IF-CNB are also useful to drastically change the third-order nonlinear optical properties. These results suggest that theoretically designed [N]IF-CNB can be attractive and challenging targets of organic synthesis for realizing novel open-shell functional conjugated macrocycles.

Dependence of aromatic and open-shell characteristics on the number of units and charged states was theoretically investigated for carbon nanobelts composed of indeno[1,2-b]fluorene units by using quantum chemical calculations.     

Radical scavenging activity of carbon nanotubes: toward appropriate selection of a radical initiator

Radical scavenging activities are attractive properties not only for scientific fields e.g. biomedicine, but for the materials industry. In this study, we report that carbon nanotubes (CNTs) can scavenge radicals from organic peroxides, while radicals from azo-type radical initiators exhibit only a few effects from the presence of CNTs. In addition, experimental results suggest the possibility that captured peroxide radicals generate active radical sites on the CNT surface, from which polymerization can take place. These results indicate the importance of selecting an appropriate radical initiator.

Carbon nanotubes scavenge radicals preferentially from peroxides, and polymerization presumably takes place from generated active radical sites on the surface.     

Perioperative and long-term outcomes after pancreaticoduodenectomy in elderly patients 80 years of age and older

Purpose

Although a pancreaticoduodenectomy (PD) has been recently regarded as a safe surgical procedure at high-volume centers, the efficacy of PD for patients 80 years of age and older is controversial. The aim of this study was to evaluate the perioperative and long-term outcomes following PD in patients 80 years of age and older.

Methods

Elderly patients 80 years of age and older who underwent PD between 2001 and 2009 were identified. The perioperative and long-term outcomes were compared with patients younger than 80 years of age.

Results

Of 561 total patients, 22 patients (3.9 %) were 80 years of age or older. Mortality occurred in one patient (4.5 %). Postoperative major complications (Clavien–Dindo classification ≥grade III) occurred in six patients (27.3 %) in this group, which was significantly higher than in patients younger than 80 years of age (P?=?0.008). The survival of the elderly patients undergoing PD for pancreatic cancer was significantly shorter than that for the same patient group with other diseases (median survival, 13 versus 82 months; P?=?0.014). Only one elderly patient with pancreatic cancer survived more than 3 years.

Conclusions

PD for pancreatic cancer in patients aged 80 and older should be carefully selected, because it is associated with a higher incidence of severe postoperative complications and a small change of long-term survival.