Antibiofilm efficacies of cold plasma and er: YAG laser on Staphylococcus aureus biofilm on titanium for nonsurgical treatment of peri-implantitis

Objectives

The aim of the present study was to compare antibiofilm efficacies of the laser in contact and noncontact application modes and cold atmospheric plasma (CAP) on Staphylococcus aureus biofilm grown on sandblasted, large grit, acid-etched (SLA) titanium discs as an in vitro model of biofilm eradication on dental implant materials.

Methods

S. aureus biofilm was matured on titanium discs for 7 days then, treated with contact and noncontact Er:YAG laser and CAP. Antibiofilm efficacy of laser and plasma treatments were evaluated with colony counting and safranin assays. Surface characteristics of titanium disc were analyzed with scanning electron microscopy and surface roughness measurements. Temperature distribution over titanium discs were presented for the thermal safety assessment of laser and plasma treatments.

Results

: CAP resulted in 6-log inactivation of S. aureus biofilm, whereas biofilm inactivation was determined as 1 and 2.7-log for noncontact and contact laser treatments, respectively. Laser and plasma treatments did not cause any alterations on the roughness of titanium discs. Contact laser treatment caused a focal temperature increase up to 58°C, whereas plasma treatment led a uniform temperature distribution on the disc within safe limits.

Conclusion

CAP showed superior antibiofilm activity on 7-day-old S. aureus biofilm grown over SLA titanium discs, compared to contact and noncontact laser treatment without temperature increase and any damage to the surface of titanium discs.

Prognostic significance of serum galectin-3 levels in patients with hepatocellular cancer and chronic viral hepatitis

BACKGROUND/AIM

Galectins affect diverse physiological and pathophysiological processes such as development, inflammation, and tumor growth. We aimed to compare serum galectin-3 levels in three patient groups with chronic hepatitis B and C virus (HBV, HCV), cirrhosis secondary to HBV or HCV, and hepatocellular carcinoma (HCC) secondary to HBV or HCV and evaluate the role of galectin-3 during HCC progression.

PATIENTS AND METHODS

Nineteen patients with hepatocellular cancer, 22 patients with cirrhosis, and 24 patients with chronic hepatitis B and C were included in this study. Serum galectin-3 levels in different liver diseases were assessed by enzyme-linked immunosorbent assay.

RESULTS

The mean galectin-3 levels were 4.61 ng/mL (±2.32) in HCC patients, 5.68 ng/mL (±2,2) in cirrhotic patients, 1.98 ng/mL (±1.50) in chronic viral hepatitis group. There were no statistical differences between HCC and cirrhotic patients (P = 0.5), but lower in chronic hepatitis group statistically compared with cirrhosis and HCC (P < 0.001, P = 0.002, respectively). In case of cirrhotic patients, galectin-3 levels were significantly higher in patients with cirrhosis secondary to HCV compared with HBV (P = 0.03). When we evaluated galectin-3 levels in HCC patients, it was found to be 3.92 ng/mL in HCC secondary to hepatitis B and 5.37 ng/mL in HCC secondary to hepatitis C.

CONCLUSION

Serum galectin-3 levels in patients with chronic HBV or HCV may guide us about progression to cirrhosis or HCC and prognosis of the disease. Especially, galectin-3 levels may be more pronounced in case of HCV.

Experimental energy resolution of a paracentric hemispherical deflector analyzer for different entry positions and bias

A specially designed hemispherical deflector analyzer (HDA) with 5-element input lens having a movable entry position R0 suitable for electron energy analysis in atomic collisions was constructed and tested. The energy resolution of the HDA was experimentally determined for three different entry positions R0 = 84, 100, 112 mm as a function of the nominal entry potential V(R0) under pre-retardation conditions. The resolution for the (conventional) entry at the mean radius R0 = 100 mm was found to be a factor of 1.6-2 times worse than the resolution for the two (paracentric) positions R0 = 84 and 112 mm at particular values of V(R0). These results provide the first experimental verification and a proof of principle of the utility of such a paracentric HDA, while demonstrating its advantages over the conventional HDA: greater dispersion with reduced angular aberrations resulting in better energy resolution without the use of any additional fringing field correction electrodes. Supporting simulations of the entire lens plus HDA spectrometer are also provided and mostly found to be within 20%-30% of experimental values. The paracentric HDA is expected to provide a lower cost and∕or more compact alternative to the conventional HDA particularly useful in modern applications utilizing a position sensitive detector.