Oxygen uptake plateau occurrence depends on oxygen kinetics and oxygen deficit accumulation

We tested the hypothesis that participants with an oxygen uptake () plateau during incremental exercise exhibit a lower VO₂‐deficit (VO_2DEF)‐accumulation in the submaximal intensity domain due to faster ramp and square wave O₂‐kinetics. Twenty‐six male participants performed a standard ramp test (increment: 30 W·min^?1), a ramp test with an individualized ramp slope and a two‐step (moderate and severe) square wave exercise followed by a ‐verification bout. VO_2DEF was calculated by the difference between individualized ramp test O₂ and O₂‐demand estimated from steady‐state O₂‐kinetics. Twenty‐four participants verified their O_2max in the verification test. Ten of them showed a plateau in the individualized ramp test. VO_2DEF at the end of this ramp test (4.34 ± 0.60 vs 4.54 ± 0.43 L) was not different between the plateau and the non‐plateau group (P > 0.05). The plateau group had a significantly (P < 0.05) lower VO_2DEF 2 minutes before termination of the individualized ramp test (2.24 ± 0.40 vs 2.78 ± 0.33 L). This coincided with a shorter mean response time (43 ± 9 vs 53 ± 7 seconds), a higher increase in O₂ per W (10.1 ± 0.2 vs 9.2 ± 0.5 mL·min^?1·W^?1) at the individualized ramp test as well as shorter time constants of moderate (36 ± 6 vs 48 ± 7 seconds) and severe (62 ± 9 vs 86 ± 10 seconds) square wave kinetics (all P < 0.05). We conclude that the O₂‐plateau occurrence requires a fast O₂‐kinetics and a low VO_2DEF‐accumulation at intensities below O_2max.     

Immunohistochemistry for c-myc and bcl-2 overexpression improves risk stratification in primary central nervous system lymphoma

Overexpression of bcl-2 and c-myc are defining features of double-expressor-lymphoma (DEL) but may also occur separately in patients with primary central nervous system lymphoma (PCNSL). Despite all progress in optimizing treatment regimen, there is lack of sufficient risk stratification models. Here, we first describe the relationship between DEL biology, the National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI), treatment response, disease progression, and mortality in PCNSL. In this study, we determined c-myc and bcl-2 status immunohistochemically in samples of 48 patients with newly diagnosed PCNSL and followed these patients for a median interval of 6.2 years. Twelve, 18, and 17 patients harbored none, one, or both DEL features. Corresponding overall response rates after first-line therapy were strongly associated with DEL biology (100%, 42%, and 44% in patients with 0, 1, or 2 DEL features). Patients with one or both DEL features had a 5-fold and 13-fold higher 5-year risk of progression and/or death than patients without DEL features. These associations prevailed after adjusting for the NCCN-IPI. DEL improved the discriminatory capability of the NCCN-IPI (P = .0001). Furthermore, we could show that addition of DEL biology to the NCCN-IPI significantly improved the score's discriminatory potential both toward progression-free survival (increase in Harell's c = 0.15, P = .005) and overall survival (increase in Harell's c = 0.11, P = .029). In conclusion, DEL biology is a strong and simple-to-use predictor of adverse outcome in PCNSL. Addition of DEL to the NCCN-IPI improves its prognostic potential. Disease progression from PCNSL harboring both DEL features is invariably fatal. This defines a novel PCNSL patient subset with a great unmet need for improved therapy.     

Melde- und Informationssystem für bedeutsame Vorkommnisse bei Strahlenanwendungen in der Medizin: Struktur,Zuständigkeiten und Meldekriterien

The increasing frequency and complexity of medical radiation exposures to humans inevitably result in higher risks of harmful unintended or accidental radiation exposures. To ensure a high level of protection and its continuous improvement, the Directive 2013/59/Euratom thus requires to systematically record and analyze both events and near-miss events as well as, in the case of their significance, to disseminate information regarding lessons learned from these events promptly and nationwide to improve radiation protection in medicine. These requirements have been transposed into German legislation by the new radiation protection law and radiation protection ordinance that entered into force simultaneously on December 31^th, 2018. The reporting and information system as provided by these regulations as well as the tasks, duties and powers of the parties involved are presented in the first part of this review article. In the second part, the established application-specified criteria for the significance – and thus the notification requirement - of (near-miss) events are itemized and explicated.     

AktivMobil – ein betriebliches Gesundheitsprogramm

Background

Workplace health promotion programs (WHPP) are becoming increasingly important. AktivMobil is a behavioral preventive WHPP that was developed for an occupational group with increased work-related strain. This study aimed to elucidate the impact of the program, consisting of a check-up session and a subsequent 20-week virtual and 6?hour personal coaching, on health-related quality of life and physical activity.

Methods

Health-related quality of life and physical activity were quantified by the Short-Form Health Survey (SF-36) and the International Physical Activity Questionnaire (IPAQ) in a quasi-experimental, controlled trial. In all, 28 employees took part in the intervention and were compared to 20 employees without intervention.

Results

The physical component summary score, physical functioning, physical role functioning, pain, general health, vitality, social functioning, mental health and health transition improved significantly in the treatment group after 20 weeks. However, no significant effects were observed for total physical activity and leisure time physical activity. In addition, there was no significant difference between treatment and control subjects at the second evaluation point.

Conclusions

The findings speak for the effectiveness of AktivMobil on promoting health-related quality of life, which is also an indicator of absenteeism. However, the combination with work-related strategies should not be ignored.

     

Increased apical enlargement contributes to excessive dentin removal in curved root canals: a stepwise microcomputed tomography study

Introduction

To determine whether increased apical enlargement would result in a complete preparation of curved canals and to progressively assess shaping quality using multiple microcomputed tomography (MCT) scans.

Methods

Ninety root canals with a curvature of 25° to 50° were selected. Five MCT scans, 1 preoperative and 4 postoperative, were acquired from each canal. Canal preparation was performed up to size 50 using 3 techniques, nickel-titanium (NiTi) hand files, Mtwo (VDW, Munich, Germany), and ProTaper (Maillefer, Ballaigue, Switzerland), by experienced operators in a dental mannequin so as to simulate the clinical conditions. At a level of 1 mm short of the working length, 2 parameters were evaluated in each of the 4 postoperative acquisitions: the percentage of the prepared outline and the amount of dentin removed (the prepared area).

Results

Statistically, there was no significant difference between the 3 systems used regarding the prepared outline. The maximum prepared outline was achieved by the use of NiTi hand files (63%; confidence interval [CI], 54%–73%), whereas Mtwo and ProTaper amounted to 58% (CI, 50%–66%) and 60% (CI, 51%–70%), respectively. In contrast, the dentin area removed by ProTaper was significantly higher than that of Mtwo and NiTi hand files.

Conclusions

Increased apical enlargement of curved canals did not result in a complete apical preparation, whereas it did lead to the unnecessary removal of dentin.