Photo-responsive azobenzene interactions promote hierarchical self-assembly of collagen triple-helical peptides to various higher-order structures

Collagen is an essential structural protein in animal tissues and plays key roles in cellular modulation. We investigated methods to discover collagen model peptides (CMPs) that would self-assemble into triple helices and then grow into supramolecular organizations with diverse morphological features, which would be valuable as biomaterials. This challenging undertaking was achieved by placing azobenzene groups on the ends of the CMPs, (GPO)_n (n = 3–10), Azo-(GPO)_n. In a dilute aqueous solution (80 μM), CD spectra indicated that the Azo-(GPO)_n (n > 4) formed triple helices due to strong hydrophobic azobenzene interactions, and that helix stability was increased with the peptide segment length. The resulting triple helices induced a specific azobenzene orientation through turned and twisted configurations as shown by CD spectra. TEM observations for the same solutions disclosed the morphologies for the Azo-CMPs. Azo-(GPO)₃, having the shortest peptide segment, showed no nanostructure, both Azo-(GPO)₄ and Azo-(GPO)₅ provided consistent well-developed nanofiber structures resembling the natural collagen fibers, and Azo-(GPO)_ns (n = 6–10) grew into flexible rod-like micelle fibers. In addition, alkyl chain-attached C_mAzo-(GPO)₅ displayed a toroidal morphology, and Azp-deg-(GPO)₅ having a hydrophilic spacer assembled into a bilayer vesicle structure. These diverse morphological features are considered to be due to the characteristics of the pre-organized triple helix units. Photo-isomerization of the azobenzene moiety brought about the disappearance of such characteristic nano-architectures. When the solution concentration was increased up to 1 wt%, only Azo-(GPO)₄ and Azo-(GPO)₅ spontaneously formed hydrogels exhibiting a satisfactory gel-to-sol transition upon UV irradiation.

Collagen is an essential structural protein in animal tissues and plays key roles in cellular modulation.     

Posterior ventricular septal perforation

We present a case in which the sandwich technique was successfully applied via right ventriculotomy for posterior infarction ventricular septal perforation 2 days after acute posterior myocardial infarction in a 73-year-old male patient. The sealant BioGlue was applied to the space between the two patches instead of gelatin–resorcinol–formaldehyde biological glue. The postoperative course was good, and the patient was discharged on day 24 after surgery with no recognized residual shunt.     

Determination of Nonspherical Morphology of Doxorubicin-Loaded Liposomes by Atomic Force Microscopy

The 3-D morphology of doxorubicin (DOX)–loaded liposomes with a size of circa 100 nm was characterized by atomic force microscopy in an aqueous environment. Prolate liposomes appear in accordance with linear expansion of DOX fiber bundles precipitated inside liposomes. Oblate and concave liposomes were simultaneously observed with increased DOX concentrations; however, their morphologies were not readily determined by 2-D cryo-TEM imaging. Precise data analysis of the 3-D parameters of each liposome allowed semiquantitative evaluation of the transformation of spherical liposomes into nonspherical—prolate, oblate, and concave liposomes. In addition, nonspherical liposomes became spherical on the replacement of the liposomal outer phase consisting of a sucrose solution, with water and subsequent water influx. All spherical liposomes transformed into oblate and concave liposomes with a return to hyperosmotic conditions, when transferred from water to sucrose solution. Furthermore, the concave liposomes did not appear under DOX incubation conditions (65°C), which could be due to the amorphous and supersaturated DOX inside the liposomes that restrained liposomal shrinkage. As atomic force microscopy has improved our ability to image 3-D morphologies of liposomes in various conditions, it is an alternative analytical tool to cryo-TEM and may have future applications in regulatory tests for quality control and assurance.     

DNA-loaded nano-adjuvant formed with a vitamin E-scaffold intracellular environmentally-responsive lipid-like material for cancer immunotherapy

Cytoplasmic DNA triggers cellular immunity via activating the stimulator of interferon genes pathway. Since DNA is degradable and membrane impermeable, delivery system would permit cytoplasmic delivery by destabilizing the endosomal membrane for the use as an adjuvant. Herein, we report on the development of a plasmid DNA (pDNA)-encapsulating lipid nanoparticle (LNP). The structural components include an SS-cleavable and pH-activated lipid-like material that mounts vitamin E as a hydrophobic scaffold, and dual sensing motifs that are responsive to the intracellular environment (ssPalmE). The pDNA-encapsulating LNP (ssPalmE-LNP) induced a high interferon-β production in Raw 264.7 cells. The subcutaneous injection of ssPalmE-LNP strongly enhanced antigen-specific cytotoxic T cell activity. The ssPalmE-LNP treatment efficiently induced antitumor effects against E.G7-OVA tumor and B16-F10 melanoma metastasis. Furthermore, when combined with an anti-programmed death 1 antibody, an extensive therapeutic antitumor effect was observed. Therefore, the ssPalmE-LNP is a promising carrier of adjuvants for cancer immunotherapy.     

Elevation of serum type IV collagen-degrading enzyme in hepatocellular carcinoma with metastasis

The activity of serum type IV collagen-degrading enzyme was measured in 21 patients with hepatocellular carcinoma, and the changes in the enzyme activity were investigated with respect to metastasis. The activity of serum type IV collagen-degrading enzyme did not increase until tumor invasion to the portal vein and intrahepatic metastasis were clearly detected ultrasonographically. Activities did not increase during the observation period in patients whose tumor grew slowly and did not invade the portal vein. Thus, the enzyme activity increases in relation to the metastasis of hepatocellular carcinoma and may be useful to detect ongoing metastases.     

Lumbar foraminal stenosis causes leg pain at rest

Purpose

Lumbar intra-spinal canal stenosis is characterized by leg pain that intensifies during walking and intermittent claudication, while leg pain at rest is a characteristic neurological symptom of lumbar disc herniation. Until now, a correlation between leg pain at rest and symptomatic foraminal stenosis has not been reported. This is a prospective and comparative study of unilateral leg pain from L5 nerve root compression due to spinal canal stenosis to determine clinical characteristics of lumbar foraminal stenosis.

Methods

Clinical and neurological findings were compared among 38 patients receiving L5–S1 transforaminal lumbar interbody fusion for L5–S1 foraminal stenosis (FS group) and 60 patients receiving L4–5 decompression or/and fusion for L4–5 intra-spinal canal stenosis (CS group).

Results

The only significant difference between the FS and CS groups in demographic clinical data was leg pain at rest. The prevalence of leg pain was significantly higher in the FS group compared to the CS group (76 vs. 35 %). The visual analogue scale for leg pain at rest was also significantly higher in the FS group than in the CS group (6.6 ± 3.1 vs. 1.3 ± 1.9).

Conclusions

Leg pain at rest is characteristic of L5–S1 foraminal stenosis.     

Outcomes of emergency surgery for acute abdomen in dialysis patients: experience of a single community hospital

Purpose

Long-term dialysis often causes physiological and metabolic problems that may affect the outcomes of surgery. The aim of this study was to elucidate whether emergency surgery for acute abdomen yields similar outcomes in dialysis patients versus non-dialysis patients.

Methods

The subjects were 126 patients who underwent emergency surgery for acute abdomen between January, 2007 and November, 2011 in our hospital. They were divided into a dialysis group (HD group; n = 9) and a non-dialysis group (non-HD group; n = 117) and their postoperative morbidity and mortality were compared.

Results

Postoperative morbidity and mortality were significantly worse in the HD group. All 9 of these patients succumbed to postoperative complications versus only 5 of the 117 patients in the non-HD group.

Conclusion

The outcomes of emergency surgery for acute abdomen were significantly worse for dialysis patients than for non-dialysis patients. Prompt diagnosis, initiation of the most suitable surgical procedure, and meticulous postoperative cares are imperative to improving the surgical outcomes of dialysis patients.     

Initial experience with proximal ligation for profunda femoris artery aneurysms: report of three cases

Profunda femoris artery aneurysms (PFAAs) are rare and difficult to diagnose in the early stage. They are often found due to the presence of complicated conditions, such as rapid expansion, rupture, or acute lower limb ischemia. Surgical procedures such as aneurysmectomy and endoaneurysmorrhaphy tend to be technically challenging because of the patient status and the extent of the aneurysm. We experienced three cases of PFAAs that were treated by proximal ligation (PL) without complete control of the distal branches. The exclusion of PFAAs was confirmed by duplex ultrasound or angiography at the end of the operation. There was no mortality in the perioperative period. During a 12-month follow-up, all cases exhibited complete exclusion of aneurysms with marked size reduction. Based on these findings, we propose that PL, with a careful follow-up for PFAA exclusion and distal limb circulation, could be an alternative treatment for complicated PFAAs.