Randomized clinical trial of ascorbic acid in the treatment of pressure ulcers

The objective of this study was to assess the effects of ascorbic acid supplementation, 500 mg twice daily in the treatment of pressure ulcers as an adjunct to standardized treatment.

The design consisted of a multicenter blinded randomized trial. The control group received 10 mg of ascorbic acid twice daily.

Patients from 11 nursing homes and 1 hospital participated.

Main outcome measures included wound survival, healing rates of wound surfaces, and clinimetric changes over 12 weeks.

Eighty-eight patients were randomized. Intention-to-treat analysis showed that the wound closure probability per unit time (i.e., the closure rate) was not higher in the intervention group than in the control group (Cox hazard ratio of 0.78 [90% precision interval, 0.44–1.39]). Mean absolute healing rates were 0.21 and 0.27 cm²/week in the intervention and control group, respectively (PI of the adjusted difference: −0.17 to 0.13). Relative healing rates and healing velocities did not show favorable results of ascorbic acid supplementation, either. A panel scored slides of the ulcers with a report mark between 1 (bad) and 10 (excellent). The improvement was 0.45 and 0.72 points per week in the intervention and control group, respectively (PI of the adjusted difference: −0.50 to 0.20). With another clinimetric index we could not show any differences, either.

These data do not support the idea that ascorbic acid supplementation (500 vs. 10 mg twice daily) speeds up the healing of pressure ulcers.     

Spatial memory impairment in patients after tumour resection: evidence for a double dissociation

Human spatial memory can be divided into multiple, partly separate cognitive processes. In this study, object location memory was studied using a set of tasks that assessed three different spatial memory aspects: positional memory, object location binding, and a combined process. Also, maze learning and spatial span memory were measured. Ten patients who had undergone intracranial tumour resection participated, and their individual results were compared with control data from 24 healthy subjects. Four patients showed selective spatial memory impairments; two patients were impaired at positional memory, and two other patients were impaired on object location binding and the combined process. This double dissociation provides further evidence for the notion that object location memory is not a unitary system, but consists of at least two separate mechanisms. In addition, spatial memory problems were predominantly present in the patients with lesions in either the right hemisphere or in the parietal lobe. These results are in agreement with previous findings on the involvement of the right hemisphere and the posterior parietal cortices in spatial processing.     

MR renography: an algorithm for calculation and correction of cortical volume averaging in medullary renographs

We evaluated a mathematical algorithm for the generation of medullary signal from raw dynamic magnetic resonance (MR) data. Five healthy volunteers were studied. MR examination consisted of a run of 100 T1-weighted coronal scans (gradient echo; TR/TE 11/3.4 msec, flip angle 60 degrees; slice thickness 6 mm; temporal resolution 2 seconds). Gadolinium-diethylene triamine pentaacetic acid (DTPA; 0. 05 mmol/kg) was injected with an injector pump (5 ml/sec). Medullary MR renographs (MRRs) were calculated for regions of interest with strong and moderate cortical volume averaging (CVA). A reference medullary MRR, devoid of CVA, was obtained. Percentual signal differences between calculated and reference medullary MRRs were estimated for each consecutive scan. Run averaged values of these differences were calculated. Mean values, after subtraction of the resting state signal, were +0.2% (SD 9.7%) and +0.7% (SD 9.0%) for areas with strong and moderate CVA, respectively. We conclude that with this algorithm reliable extraction of medullary MRRs is feasible, providing a unique tool for clinical evaluation of medullary disease. J. Magn. Reson. Imaging 2000;12:453-459.     

Societal Effects Are a Major Factor for the Uptake of the Coronavirus Disease 2019 (COVID-19) Digital Contact Tracing App in The Netherlands

ObjectivesOur study investigates the extent to which uptake of a COVID-19 digital contact-tracing (DCT) app among the Dutch population is affected by its configurations, its societal effects, and government policies toward such an app.MethodsWe performed a discrete choice experiment among Dutch adults including 7 attributes, that is, who gets a notification, waiting time for testing, possibility for shops to refuse customers who have not installed the app, stopping condition for contact tracing, number of people unjustifiably quarantined, number of deaths prevented, and number of households with financial problems prevented. The data were analyzed by means of panel mixed logit models.ResultsThe prevention of deaths and financial problems of households had a very strong influence on the uptake of the app. Predicted app uptake rates ranged from 24% to 78% for the worst and best possible app for these societal effects. We found a strong positive relationship between people’s trust in government and people’s propensity to install the DCT app.ConclusionsThe uptake levels we find are much more volatile than the uptake levels predicted in comparable studies that did not include societal effects in their discrete choice experiments. Our finding that the societal effects are a major factor in the uptake of the DCT app results in a chicken-or-the-egg causality dilemma. That is, the societal effects of the app are severely influenced by the uptake of the app, but the uptake of the app is severely influenced by its societal effects.     

Reduced sensitivity in the recognition of anger and disgust in social anxiety disorder

Introduction. The aim of this study was to investigate the recognition of facial expressions in patients with a generalised social anxiety disorder. It is well documented that in different psychiatric disorders (e.g., depression, schizophrenia) patients may show an altered processing of emotions. However, in generalised social anxiety, emotion recognition has not been studied.

Methods. 24 Patients with generalised social anxiety disorder and 26 healthy controls, matched on age, education, and sex were included. The task entailed the emotional labelling of faces with different facial expressions (happiness, fear, disgust, sadness, surprise, anger) presented in different intensities. Subjects were asked to make a forced‐choice response.

Results. These revealed that patients with a generalised social anxiety disorder were less sensitive for the negative facial expressions of anger and disgust compared to the control group.

Conclusions. This deficit could play a role in the development and/or the maintaining of the social anxiety. Both explanations are discussed.