Biomedical subjects

Mark M Span

Publications and source records attributed to Mark M Span.

8 recordsLinked to original sources

PubMed2006

Cognitive self-therapy for chronic depression and anxiety: a multi-centre randomized controlled study.

BACKGROUND: Non-professional treatment programmes are presumed to relieve the extensive need for care of anxiety and depression disorders. This study investigates the effectiveness of cognitive self- therapy (CST) in the treatment of depression or generalized anxiety disorder. METHOD: Patients (n=151) were randomized to receive CST or treatment as usual (TAU) in a trial lasting for 18 months, measuring symptoms (SCL-90; main outcome), social functions, quality of life and utilization of care. RESULTS: Patients in both conditions improved significantly, but no difference was found between the conditions. Reduction of symptoms, improvement of social functions and medical utilization were maintained at the end of the 18 months. Medical care utilization (therapist contact and hospitalization) was lower for CST than for TAU. No suicides occurred. CONCLUSIONS: Cognitive self-therapy is likely to decrease the need for care of chronic depression and anxiety disorders, but it has not been proven to be more effective than treatment as usual.

Adult↗

PubMed2006

Safe and unsafe duration of fasting for children with MCAD deficiency.

OBJECTIVE: To study the safe and unsafe duration of fasting in children with medium chain acyl-Coenzyme A dehydrogenase (MCAD) deficiency, the literature and the database on Dutch MCAD-deficient patients were searched for data on fasting studies in patients with MCAD deficiency. MATERIALS AND METHODS: These data were extended with information on fasting studies performed on our patients with MCAD deficiency known in the Beatrix Children's Hospital, UMC Groningen, The Netherlands. The data reflect considerable inter-individual variation and overlap between safe and unsafe duration of fasting. RESULTS: In six out of 35 fasting tests, symptoms were reported before hypoglycaemia was observed. Until 1 year of age, the median safe and unsafe duration of fasting was 12 hours (n=7, range 8-19 hours) and 18 hours (n=5, range 15-20 hours), respectively. After the first year of life, the median safe and unsafe duration of fasting was 18 hours (n=17, range 10-24 hours) and 20 hours (n=9, range 13-32 hours), respectively. CONCLUSION: Therefore, to conclude, we recommend a maximum duration of fasting in children with MCAD deficiency of 8 hours between 6 months and 1 year of age, 10 hours in the second year of life and 12 hours thereafter. From this study, no conclusions can be drawn on the duration of fasting during situations of intercurrent illness, especially with fever.

Acyl-CoA Dehydrogenase↗

PubMed2006

TRAIL-receptor expression is an independent prognostic factor for survival in patients with a primary glioblastoma multiforme.

PURPOSE: In order to improve the survival of patients with a glioblastoma multiforme tumor (GBM), new therapeutic strategies must be developed. The use of a death inducing ligand such as TRAIL (TNF Related Apoptosis Inducing Ligand) seems a promising innovative therapy. The aim of this study was to quantify the expression of the death regulating receptors TRAIL-R1, TRAIL-R2 and TRAIL on primary GBM specimens and to correlate this expression with survival. EXPERIMENTAL DESIGN: Expression of TRAIL and TRAIL-receptors was assessed by immunohistochemistry, both quantitatively (% of positive tumor cells) and semi-quantitatively (staining intensity) within both the perinecrotic and intermediate tumor zones of primary GBM specimens. RT-PCR of GBM tissue was performed to show expression of TRAIL receptor mRNA. RESULTS: Immunohistochemistry showed a slight diffuse intracytoplasmic and a stronger membranous staining for TRAIL and TRAIL receptors in tumor cells. Semi-quantitative expression of TRAIL showed a significantly higher expression of TRAIL in the perinecrotic zone than in the intermediate zone of the tumor (P=0.0001). TRAIL-R2 expression was significantly higher expressed than TRAIL-R1 (P=0.005). The antigenic load of TRAIL-R2 was positively correlated with survival (P=0.02). Multivariate analysis of TRAIL-R1 within the study group (n=62) showed that age, gender, staining intensity, antigenic load, % of TRAIL-R1 expression, were not statistically correlated with survival however radiotherapy was significantly correlated (multivariate analysis: age: P=0.15; gender: P=0.64; staining intensity: P=0.17; antigenic load: P=0.056; % of TRAIL-R1 expression: P=0.058; radiotherapy: P=0.0001). Subgroup analysis of patients who had received radiotherapy (n=47) showed a significant association of % of TRAIL-R1 expression and the antigenic load of TRAIL-R1 with survival (multivariate analysis: P=0.036, respectively, P=0.023). Multivariate analysis of TRAIL-R2 staining intensity and antigenic load, within the study group (P=0.004, respectively, P=0.03) and the subgroup (P=0.002, respectively, P=0.004), showed a significant association with survival. RT-PCR analysis detected a negative relation between the amount of TRAIL-R1 mRNA and the WHO grade of astrocytic tumors (P=0.03). CONCLUSIONS: TRAIL-R1 and TRAIL-R2 expression on tumor cells are independent prognostic factors for survival in patients with a glioblastoma multiforme. Both receptors could be targets for TRAIL therapy. As TRAIL-R2 is more expressed, in comparison with TRAIL-R1, on GBM tumor cells, TRAIL-R2 seems to be of more importance as a target for future TRAIL therapy than TRAIL-R1.

Apoptosis↗

PubMed2006

Noninferiority testing in cost-minimization studies: Practical issues concerning power analysis.

OBJECTIVES: In cost-minimization studies, it is important to establish noninferiority in the clinical effect of the treatments under investigation. The relationship between the proportion of patients reaching the end point in a study, equivalence limit (delta), and power is investigated in the context of cost-minimization studies with dichotomous clinical end points. Two formulations of the null-hypothesis, absolute and relative formulations of delta, will be explored. METHODS: Sensitivity analysis was performed, in which the effect of the predicted proportions and delta on the power in a noninferiority setting was investigated. The patterns found are discussed in terms of the practical relevance within the cost-minimization framework. RESULTS: Sensitivity analyses show different patterns of results for both null-hypotheses. The differences in these results originate from the way delta is expressed. By expressing delta as absolute difference, power grows quite fast when sample proportions are smaller than expected. In the case of a proportional delta at small sample proportions, the power to establish noninferiority remains low. CONCLUSIONS: To obtain valid results from a cost-minimization study, care has to be taken to adapt the correct methodology for noninferiority testing in clinical outcomes. Defining delta in terms of absolute differences between treatments can lead to obscured results. Although conservative, the expression of delta as a proportion of the effectiveness of the treatment as usual is found to be closer to clinical practice. The inflated delta, resulting from smaller clinical effects than expected when absolute formulation is applied, thus can be avoided.

Cost Control↗

PubMed2005

Incomplete quality of life data in lung transplant research: comparing cross sectional, repeated measures ANOVA, and multi-level analysis.

BACKGROUND: In longitudinal studies on Health Related Quality of Life (HRQL) it frequently occurs that patients have one or more missing forms, which may cause bias, and reduce the sample size. Aims of the present study were to address the problem of missing data in the field of lung transplantation (LgTX) and HRQL, to compare results obtained with different methods of analysis, and to show the value of each type of statistical method used to summarize data. METHODS: Results from cross-sectional analysis, repeated measures on complete cases (ANOVA), and a multi-level analysis were compared. The scores on the dimension 'energy' of the Nottingham Health Profile (NHP) after transplantation were used to illustrate the differences between methods. RESULTS: Compared to repeated measures ANOVA, the cross-sectional and multi-level analysis included more patients, and allowed for a longer period of follow-up. In contrast to the cross sectional analyses, in the complete case analysis, and the multi-level analysis, the correlation between different time points was taken into account. Patterns over time of the three methods were comparable. In general, results from repeated measures ANOVA showed the most favorable energy scores, and results from the multi-level analysis the least favorable. Due to the separate subgroups per time point in the cross-sectional analysis, and the relatively small number of patients in the repeated measures ANOVA, inclusion of predictors was only possible in the multi-level analysis. CONCLUSION: Results obtained with the various methods of analysis differed, indicating some reduction of bias took place. Multi-level analysis is a useful approach to study changes over time in a data set where missing data, to reduce bias, make efficient use of available data, and to include predictors, in studies concerning the effects of LgTX on HRQL.

Adult↗

PubMed2005

Endovascular treatment of popliteal artery aneurysms: results of a prospective cohort study.

OBJECTIVE: Popliteal artery aneurysms can be treated endovascularly with less perioperative morbidity compared with open repair. To evaluate suitability of the endovascular technique and the clinical results of this treatment, we analyzed a prospective cohort of consecutive popliteal aneurysms referred to a tertiary university vascular center. METHODS: All popliteal artery aneurysms between June 1998 and June 2004 that measured >20 mm in diameter were analyzed for endovascular repair. Anatomic suitability was based largely on quality of the proximal and distal landing zone as determined by angiography. Endovascular treatment was performed by using a nitinol-supported expanded polytetrafluoroethylene lined stent graft introduced through the common femoral artery. RESULTS: We analyzed 67 aneurysms in 57 patients. Ten aneurysms (15%) were excluded from endovascular repair, or from any repair at all, for various reasons. The remaining 57 (85%) were treated endovascularly, of which 5 were treated emergently for acute ischemia. During a mean 24-month follow-up, 12 stent grafts (21%) occluded. Primary and secondary patency rates were 80% and 90% at 1 year, and 77% and 87% at 2 years of follow-up. Postoperative treatment with clopidogrel proved to be the only significant predictor for success. CONCLUSIONS: Endovascular repair of a popliteal artery aneurysm is feasible. Changes in the material used and the addition of clopidogrel may improve patency rates.

Aged↗

PubMed2004

Age-related changes in the efficiency of cognitive processing across the life span.

The global-speed and the specific-gain/loss hypotheses have been dominant theoretical frameworks in the recent literature on cognitive development and aging. Few attempts have been made to explicitly assess the predictive power of the two frameworks against each other. We evaluated the extent to which age changes in performance in executive function tasks (involving response selection, response suppression, working memory, and adaptive control) depend on age-related changes in global information-processing speed. Our sample consisted of children, adolescents, adults and seniors. Analysis of covariance and structural equation modeling revealed a mixed pattern of results. Controlling for global speed removed the child vs. adult differences in the speed of responding on the executive function tasks but the senior vs. adult differences remained. This mixed pattern of findings was interpreted to suggest that the effects of advancing age on the speed of responding are mediated by a global mechanism during childhood but during senescence the efficiency of executive functioning seems particularly vulnerable to the effects of age.

Adolescent↗

PubMed2002

Perseverative behavior and adaptive control in older adults: performance monitoring, rule induction, and set shifting.

Older adults, like patients with dorsolateral frontal lobe lesions, have been shown to be progressively susceptible to errors of perseveration in the Wisconsin Card Sorting Test (WCST). This deficit may result from several types of endogenous adaptive control abilities. First, to enable behavioral modifications in response to sudden changes in task demands, one has to consider and evaluate the possible alternative categorization rules and select one for further testing (rule induction). Second, to perform the required shift appropriately, one should suppress the no-longer relevant task set and replace it by an appropriate new one (set shifting). Third, however, proper application of rule-induction and set-shifting abilities requires the ability to monitor and interpret task cues and feedback signals appropriately to guide behavior and to recognize the need to apply rule-shift operations (performance monitoring). To explore the extent to which these different endogenous adaptive control abilities are differentially sensitive to the effect of aging, young and older adults were tested in two experiments using WCST-like tasks. From the finding that older adults were not able to capitalize on explicit shift cues (either nonspecific or specific) the inference can be drawn that basic set-shifting abilities, rather than rule-induction or performance-monitoring abilities, were the primary factor responsible for the increased tendency to perseverate as adults grow into senescence.

Adaptation, Psychological↗