Direct visualization of translesion DNA synthesis polymerase IV at the replisome.

In bacterial cells, DNA damage tolerance is manifested by the action of translesion DNA polymerases that can synthesize DNA across template lesions that typically block the replicative DNA polymerase III. It has been suggested that one of these translesion DNA synthesis DNA polymerases, DNA polymerase IV, can either act in concert with the replisome, switching places on the ß sliding clamp with DNA polymerase III to bypass the template damage, or act subsequent to the replisome skipping over the template lesion in the gap in nascent DNA left behind as the replisome continues downstream. Evidence exists in support of both mechanisms. Using single-molecule analyses, we show that DNA polymerase IV associates with the replisome in a concentration-dependent manner and remains associated over long stretches of replication fork progression under unstressed conditions. This association slows the replisome, requires DNA polymerase IV binding to the ß clamp but not its catalytic activity, and is reinforced by the presence of the γ subunit of the ß clamp-loading DnaX complex in the DNA polymerase III holoenzyme. Thus, DNA damage is not required for association of DNA polymerase IV with the replisome. We suggest that under stress conditions such as induction of the SOS response, the association of DNA polymerase IV with the replisome provides both a surveillance/bypass mechanism and a means to slow replication fork progression, thereby reducing the frequency of collisions with template damage and the overall mutagenic potential.

Efficiency of a biodegradable gel containing hyaluronic acid and berberine hydrochloride in endoscopic sinus surgery (ESS): A prospective comparative study.

PURPOSE: To evaluate the efficiency of a biodegradable gel containing hyaluronic acid and berberine hydrochloride in endoscopic sinus surgery. METHODS: Sixty-six chronic rhinosinusitis patients with or without nasal polyps who underwent bilateral endoscopic sinus surgery (ESS) were randomly received a biodegradable gel containing hyaluronic acid and berberine hydrochloride or merocel in both middle meatal spacers at the end procedure of ESS. Lund-Kennedy endoscopic score (LKES) was used to examine status of nasal cavity on preoperative day and postoperative day 1 to 7. The LKES ratio was calculated as the LKES on postoperative day divided into the LKES on preoperative day. Visual analogue score (VAS) was used to assess patient's status from the first postoperative day to the hospital discharge day. The average VAS during hospital stays was calculated by the sum of VAS in each examination day divided into the number of examined day. The LKES ratio, the average of VAS during hospital stays and length of hospitalized day of the patients were used as clinical outcome indices in early stage after surgery. A general linear model adjusted for confounding factors was used for data analysis. RESULTS: Adjusted mean of LKES ratio were lower in group used biodegrable gel of hyaruloic acid and berberin hydrochlode (study group) than those in merocele group in the postoperative day 1 to day 7. However, significant difference was found in the adjusted mean of LKES ratio on the postoperative day 2 to 6. Similarly, the adjusted mean of VAS during hospital stays and length of hospitalized day after surgery in study group were significantly decreased as compared with those in merocele group. CONCLUSIONS: Biodegradable material containing hyaluronic acid and berberine hydrochloride was more effective than merocel in length of hospital stay, post-operative symptoms, and sinus cavity's status in early stage after ESS.

Vitamin E (alpha-tocopherol) production by the marine microalgae Dunaliella tertiolecta and Tetraselmis suecica in batch cultivation.

Batch experiments with Dunaliella tertiolecta and Tetraselmis suecica were performed to investigate alpha-tocopherol (alpha-T) production in time, in order to assess the effect of light availability per cell on the production of this antioxidant. In D. tertiolecta alpha-T content increased during growth, in other words, as the cell density increased and the light availability per cell decreased. In T. suecica the pattern was different: alpha-T content was highest during the exponential phase, decreased significantly during the linear phase and increased again towards the end of the cultivation. Chlorophyll (chl-a) content of T. suecica cells decreased after the exponential phase, instead of the expected increase typically observed in shade-adapted cells, suggesting that the culture was nutrient limited. An experiment with extra nutrients showed that chl-a and alpha-T content increased significantly during both the linear and the stationary phase when compared with values in nutrient-deficient conditions. No correlation between alpha-T and chl-a was observed. Our results indicate that diminished light availability does not limit alpha-T production in D. tertiolecta and T. suecica, opening up the possibility of using high cell density, light-limited cultures for the production of this commercially interesting compound.

Potent vasodilatory effect of fasudil on radial artery graft in coronary artery bypass operations.

BACKGROUND: The radial artery (RA) is a useful conduit for coronary artery bypass grafting (CABG) but is susceptible to vasospasm during harvesting. We evaluated the usefulness of fasudil, a Rho kinase inhibitor, in dilating the RA graft and increasing graft free flow (GFF) compared with the conventional graft-dilating agents papaverine and verapamil-nitroglycerin (VG). METHODS: Between June 2012 and January 2013, 45 patients with ischemic heart disease who underwent isolated CABG using the RA were enrolled and randomly assigned to fasudil (n = 15), papaverine (n = 15), or VG (n = 15). Fasudil (2.67 mmol/L), papaverine (1.0 mmol/L) mixed with heparinized blood, or VG (30 µmol/L each of verapamil and nitroglycerin) was injected intraluminally into the RA graft after harvesting. Main outcome measures were RA GFF, hemodynamic changes, and histopathologic examination of the RA. RESULTS: In the fasudil group, GFF increased significantly (p < 0.001) from 36.8 ± 20.4 at baseline to 148.0 ± 88.3 mL/min after injection. GFF increased significantly (p < 0.001) from 36.0 ± 19.0 to 72.3 ± 36.7 mL/min in the papaverine group and increased significantly (p < 0.001) from 39.5 ± 23.3 to 64.3 ± 29.9 mL/min in the VG group. The GFF was significantly higher (p = 0.001) in fasudil-treated RA than in papaverine- or VG-treated RA. Histopathologically, RA graft diameter was markedly increased after fasudil injection, and the structure of the multiple elastic lamellae was intact. Blood pressure did not change significantly after drug injection in all groups. CONCLUSIONS: Fasudil exhibited a very potent vasodilatory effect on the RA compared with conventional papaverine or VG, resulting in increased GFF. This agent is useful for dilating RA grafts in CABG.

Assessment of a new type I endoleak repair technique using an anchoring device.

OBJECTIVE: Type I endoleaks are one of the most frequent and life-threatening complications of thoracic endovascular aortic repair. This study aimed to assess the use of suture-anchoring devices for repairing type I endoleaks. METHODS: The descending aortic aneurysm model (saccular type) was made by side-to-end anastomosis to a Dacron graft. A Matsui-Kitamura stent graft was deployed to create a proximal type I endoleak. Approximately 5 mm above the upper rim of the anastomosis, the aorta was punctured by the pistol of the suture-anchoring device with a T-shaped bar under fluoroscopy. Sutures were applied until angiography showed the absence of a type I endoleak. During the process, two pressure measurements were used to perform continuous assessments of aortic pressure and intra-aneurysm sac pressure. RESULTS: A mean ± SD of 5 ± 1 anchoring shots were used to eliminate type I endoleaks. The device performed well, and no complications were observed. The mean ± SD intrasac pressures before stent graft deployment, during endoleak maintenance, and after repair were 118 ± 5, 61 ± 4, and 26 ± 5 mm Hg, respectively. The postrepair pressure was significantly decreased (P < 0.001; Student t test). CONCLUSIONS: Despite some anatomic and clinical limitations identified during the experiments, the effectiveness of the suture-anchoring device was confirmed. Further improvement of the device will soon lead to its use as a less invasive endoleak repair procedure.