Long-term predictive power of heart rate variability on all-cause mortality in the diabetic population

To examine the long-term predictive power of heart rate variability (HRV) on all-cause mortality in randomly selected diabetic individuals. A total of 240 diabetic persons were randomly selected from the diabetic population. A 24-h ECG was obtained for each person included and analysed on the Pathfinder 700. In the RR Tools Program time (SDNN, SDANN, SDNN index, RMSSD, NN50, Triangular index) and frequency domain parameters (total power, VLF, LF, LFnorm, HF, HFnorm, HF/LF) were computed. After 15½ years vital statistics were obtained. The analysis included 165 persons with acceptable ECG recordings. 81 individuals (49%) died during follow-up. Correcting for age and gender we found that in time domain, only the SDNN index was a significant mortality predictor but in the frequency domain, all parameters were significantly associated with death. In multivariate analysis only the power in the low frequency band was an independent predictor. During the period following the first 5 years, the baseline LF continued to be a significant predictor of mortality. This long-term follow-up study indicates that the LF power is the strongest HRV predictor with regard to mortality. A reduced HRV at baseline still holds prognostic information after 5 years.     

Intra-rater variability in low-grade glioma segmentation

Assessment of size and growth are key radiological factors in low-grade gliomas (LGGs), both for prognostication and treatment evaluation, but the reliability of LGG-segmentation is scarcely studied. With a diffuse and invasive growth pattern, usually without contrast enhancement, these tumors can be difficult to delineate. The aim of this study was to investigate the intra-observer variability in LGG-segmentation for a radiologist without prior segmentation experience. Pre-operative 3D FLAIR images of 23 LGGs were segmented three times in the software 3D Slicer. Tumor volumes were calculated, together with the absolute and relative difference between the segmentations. To quantify the intra-rater variability, we used the Jaccard coefficient comparing both two (J2) and three (J3) segmentations as well as the Hausdorff Distance (HD). The variability measured with J2 improved significantly between the two last segmentations compared to the two first, going from 0.87 to 0.90 (p?=?0.04). Between the last two segmentations, larger tumors showed a tendency towards smaller relative volume difference (p?=?0.07), while tumors with well-defined borders had significantly less variability measured with both J2 (p?=?0.04) and HD (p?<?0.01). We found no significant relationship between variability and histological sub-types or Apparent Diffusion Coefficients (ADC). We found that the intra-rater variability can be considerable in serial LGG-segmentation, but the variability seems to decrease with experience and higher grade of border conspicuity. Our findings highlight that some criteria defining tumor borders and progression in 3D volumetric segmentation is needed, if moving from 2D to 3D assessment of size and growth of LGGs.

     

Effect of electric toothbrush on residents' oral hygiene: a randomized clinical trial in nursing homes

A single‐blinded, randomized controlled clinical trial was performed to investigate the effect of electric toothbrushes (ET) compared with manual toothbrushes (MT) on residents in nursing homes and to evaluate the caregiver's opinion on ET. A sample of 180 nursing‐home residents were given either a new ET or a new MT. Oral examinations were performed to measure dental hygiene, using the Oral Hygiene Index‐Simplified (OHI‐S). Both groups received the same instructions for use. After 2 months participants were re‐examined. Questionnaires were then sent to their caregivers. Participants' mean age was 86.1 ± 7.7 yr, and the mean number of remaining teeth was 20 ± 5.6. No specific intervention effect was found for ET. Both groups showed identical improvements in the OHI‐S, from 1.27 ± 0.63 at baseline (the mean value for all participants) to 1.01 ± 0.53 after 2 months. Of 152 caregivers who responded to the questionnaire, the majority evaluated ET to be beneficial and less time‐consuming compared with MT, also for demented residents. In a frail population, no difference is found in the effect of ET compared with MT. However, the ET appears to be a useful aid for residents who receive assistance with dental hygiene.     

Visual loss after use of intraocular silicone oil associated with thinning of inner retinal layers

Purpose: To investigate the incidence and cause of severe visual loss following use and removal of intraocular silicone oil (SiO) after uncomplicated vitrectomy and SiO injection for primary rhegmatogenous retinal detachment (RRD). Methods: Consecutive case series of 216 patients operated with vitrectomy for primary RRD in 2004–2005. In 162 eyes, SiO (5500 centiStoke) had been used as intravitreal tamponade and in 54 eyes gas (perflouropropane, C₃F₈) had been used. Following chart review, we identified 16 eyes in 16 patients (nine SiO eyes, seven gas eyes) with macula‐on and documented visual acuity ≥6/12 before surgery, where SiO had been removed, cataract surgery performed and no re‐detachment had occurred. Examinations included best‐corrected visual acuity (BCVA) and high‐definition optical coherence tomography (OCT) of the macular area. Results: Preoperative characteristics were identical between SiO and gas eyes. Postoperative BCVA was significantly worse in SiO eyes (>6/24) compared to gas eyes (>6/7.5), p = 0.005. Three of 9 (33%) SiO eyes had final BCVA ≤6/60 and 67% had final BCVA ≤6/12. No gas eyes had final BCVA <6/9. Macular OCT revealed thinning of inner retinal layers in SiO‐operated eyes (5148 pixels) compared to gas‐operated eyes (6897 pixels), p < 0.002. No other visually significant structural differences were found. Conclusion: Severe visual loss after SiO use was observed in 1/3 of patients with otherwise good visual potential. The visual loss was associated with a significant reduction in inner retinal thickness indicating neuronal cell loss in the macular area as a possible explanation.     

Variation in mitochondrial DNA levels in muscle from normal controls. Is depletion of mtDNA in patients with mitochondrial myopathy a distinct clinical syndrome?

Summary Recent studies have identified a group of patients with cytochrome oxidase (COX) deficiency presenting in infancy associated with a deficiency of mtDNA in muscle or other affected tissue (Moraes et al 1991). We used a novel approach to compare the level of mitochondrial (mtDNA) compared to nuclear DNA in skeletal muscle from a group of patients and controls, based on dot blots that were hybridized with a mtDNA probe labelled with³⁵S[dCTP] and a reference nuclear DNA probe labelled with [³²P]dCTP.The ratio of mtDNA to nuclear DNA varied in samples from different muscles of the same individual. Secondly, fetal muscle had very low levels of mtDNA compared to nuclear DNA, and data from older controls (cross-sectional rather than sequential) suggest that this increases rapidly over the first 3 months after birth and thereafter more slowly. Four patients with COX deficiency had levels of mtDNA that were below the age-specific range defined by normal quadriceps muscle. The clinical features of two of these patients were similar to earlier case reports of mtDNA depletion. In three patients the clinical course was relatively benign compared to cases that have previously been described.Levels of mtDNA in skeletal muscle from some patients with other forms of muscle disease were also found to be low, suggesting that mtDNA depletion, possibly related to depletion of mitochondria, may be a relatively non-specific response of muscle to various pathological processes. However, there does appear to be a distinctive group of young patients with reduced cytochrome oxidase activity in muscle, in whom marked mtDNA depletion reflects the primary defect.