DNA repair gene expression in biological tissues exposed to low-intensity infrared laser

Special properties of laser light have led to its usefulness in many applications in therapy. Excitation of endogenous chromophores in biotissues and generation of free radicals could be involved in its biological effects. DNA lesions induced by free radicals are repaired by base excision repair pathway. In this work, we evaluated the expression of APE1 and OGG1 genes related to repair of DNA lesions induced by free radicals. Skin and muscle tissues of Wistar rats were exposed to low-intensity infrared laser at different fluences and frequencies. After laser exposition of 1 and 24 h, tissue samples were withdrawn for total RNA extraction, cDNA synthesis, and evaluation of APE1 and OGG1 gene expression by quantitative polymerase chain reaction. Data obtained show that laser radiation alters the expression of APE1 and OGG1 mRNA differently in skin and muscle tissues of Wistar rats depending of the fluence, frequency, and time after exposure. Our study suggests that low-intensity infrared laser affects expression of genes involved in repair of DNA lesions by base excision repair pathway.     

Antibiotics produced by Streptomyces

Streptomyces is a genus of Gram-positive bacteria that grows in various environments, and its shape resembles filamentous fungi. The morphological differentiation of Streptomyces involves the formation of a layer of hyphae that can differentiate into a chain of spores. The most interesting property of Streptomyces is the ability to produce bioactive secondary metabolites, such as antifungals, antivirals, antitumorals, anti-hypertensives, immunosuppressants, and especially antibiotics. The production of most antibiotics is species specific, and these secondary metabolites are important for Streptomyces species in order to compete with other microorganisms that come in contact, even within the same genre. Despite the success of the discovery of antibiotics, and advances in the techniques of their production, infectious diseases still remain the second leading cause of death worldwide, and bacterial infections cause approximately 17 million deaths annually, affecting mainly children and the elderly. Self-medication and overuse of antibiotics is another important factor that contributes to resistance, reducing the lifetime of the antibiotic, thus causing the constant need for research and development of new antibiotics.     

Identifying and Addressing Preventable Process Errors in Trauma Care

Background

Management of the acute trauma patient is complex, with potential for error and adverse events. Avoidable injuries and deaths are not well understood. Analysis of error incidence, type, and severity can aid in greater understanding of the root causes and guide future development of error reduction strategies.

Methods

Weekly case review meetings for a UK trauma center were retrospectively reviewed over 1 year. Errors were identified and corroborated with case-note review by a reviewer blinded to any identified events. All events were classified according to the Joint Commission on Accreditation of Healthcare Organisations taxonomy and were typified as structural or process errors and omission or commission errors.

Results

A total of 1,752 major trauma patients were admitted over the study period, and 169 preventable errors were identified through analysis of case review meetings and case-note review. Clear patient harm was identified in 3.6 % of cases, with risk of harm in 30 %. Most errors occurred during the initial phase of care in the emergency department (51 %) and resulted most commonly in delays (56 %). The majority of errors were identified as process-related (88 %), with 62 % of them considered errors of omission.

Conclusions

This study reports error incidence in trauma and typifies them according to type and root cause. It identifies process errors and errors of omission in particular as the most common recurring events. Error theory suggests that protocols or checklists may most effectively address these errors. Further study should be prospective and may aid in the development of such interventions.     

Single-incision transumbilical levels 1 and 2 axillary lymph node dissection using a flexible endoscope in human cadaveric models

Background

The use of the flexible endoscope as a surgical platform potentially exposes a range of new surgical approaches and benefits yet to be fully defined. A new method using the flexible endoscope to undertake axillary dissection for breast cancer treatment is explored together with an investigation into its acceptability to the general public.

Methods

Endoscopic axillary dissection via a transumbilical approach using the flexible endoscope passed subcutaneously from the umbilicus is described for four human cadaveric axillas. A questionnaire, validated by clinicians, explored the general public’s reaction to the approach and how it might be influenced by potentially serious morbidity such as an increased rate of cancer recurrence.

Results

All axillas were accessed successfully via the transumbilical approach. Levels 1 and 2 axillary dissection was attempted on four axillas. Scarring from previous axillary surgery prevented dissection in one case. In the remaining three cases, respectively 12, 11, and 14 lymph nodes were harvested. The operative times improved with each case, from 1080 to 390 min. A total of 127 people responded to the questionnaire, with 73 % preferring the described approach over the open and periareolar alternatives when morbidities were considered equivalent. When a hypothetical elevated risk of cancer recurrence was included with the transumbilical approach, one-fifth of the public still accepted the approach due to the likelihood of a superior cosmesis.

Conclusion

The use of the flexible endoscope for oncologically safe levels 1 and 2 axillary dissection is possible and would be acceptable to the general public if it were clinically approved. However, significant challenges with the current endoscopic equipment and relevant instrumentation limit the potential of the technique. Technical innovation in terms of new instrument design with improved ergonomics will reduce long operating times and fatigue, thus ensuring surgical acceptance of the flexible endoscope.     

Cardiorespiratory fitness is not associated with risk of venous thromboembolism: a cohort study

Abstract

Objectives. The inverse and independent association between cardiorespiratory fitness (CRF) and arterial thrombotic disease is well established. However, the potential association between CRF and venous thromboembolism (VTE) is not well known. We aimed to assess the prospective association of CRF with the risk of VTE. Design. Cardiorespiratory fitness, as measured by maximal oxygen uptake (VO_2max), was assessed using a respiratory gas exchange analyser in 2,249 men aged 42–61 years without a history of VTE at baseline in the Kuopio Ischemic Heart Disease prospective cohort. Cox-regression models were used to calculate hazard ratios (HR) with 95% confidence interval (CI) for VTE. We corrected for within-person variability in CRF levels using data from repeat measurements taken several years apart. Results. There were 144 (6.4%) incident VTE events recorded during a median follow-up of 25.2 years. The age-adjusted regression dilution ratio of CRF was 0.58 (95% CI: 0.53–0.64). The risk of VTE did not significantly decrease per 1 standard deviation increase in CRF in age-adjusted analysis (HR 0.90; 95% CI 0.75–1.08). The association remained consistent in analyses adjusted for several established and emerging risk factors (HR 0.90; 95% CI 0.73–1.12). The corresponding adjusted HRs were 0.80 (95% CI: 0.52–1.23) and 0.82 (95% CI: 0.51–1.32) respectively, when comparing the extreme tertiles of CRF levels. Conclusions. In a middle-aged Caucasian male population, CRF was not associated with future risk of VTE. Further studies are required to confirm and to generalize these findings, particulary in women and other age groups.     

Selective enamel etching: effect on marginal adaptation of self-etch LED-cured bond systems in aged Class I composite restorations

The aim of this study was to evaluate the influence of previous enamel etch and light emitting diode (LED) curing on gap formation of self-etch adhesive systems in Class I composite restorations after thermomechanical aging (TMA). Thus, on 192 human molars, a box-shaped Class I cavity was prepared maintaining enamel margins. Self-etch adhesives (Clearfil SE and Clearfil S3) were used to restore the preparation with a microhybrid composite. Before application of the adhesives, half of the teeth were enamel etched for 15 seconds with 37% phosphoric acid; the other half were not etched. For the photoactivation of the adhesives and composite, three light-curing units (LCUs) were used: one polywave (Ultra-Lume LED 5, UL) and two single-peak (FlashLite 1401, FL and Radii-cal, RD) LEDs. After this, epoxy resin replicas of the occlusal surface were made, and the specimens were submitted to TMA. New replicas were made from the aged specimens for marginal adaptation analysis by scanning electron microscopy. Data were submitted to Kruskal-Wallis and Wilcoxon tests (α=0.05). Before TMA, when enamel was etched before the application of S3, no gap formation was observed; however, there were gaps at the interface for the other tested conditions, with a statistical difference (p≤0.05). After TMA, the selective enamel etching previous to the S3 application, regardless of the LCU, promoted higher marginal adaptation compared to the other tested groups (p≤0.05). Prior to TMA, higher marginal integrity was observed, in comparison with specimens after TMA (p≤0.05). With regard to Clearfil SE and Clearfil Tri-S cured with FL, no differences of gap formation were found between before and after aging (5.3 ± 3.8 and 7.4 ± 7.5, respectively), especially when the Clearfil Tri-S was used in the conventional protocol. When cured with RD or UL and not etched, Clearfil Tri-S presented the higher gap formation. In conclusion, additional enamel etching promoted better marginal integrity for Clearfil Tri-S, showing it to be an efficient technique for Class I composite restorations. The two-step self-etch adhesive was not influenced by selective enamel etching or by the LED-curing unit.