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At least 217 records · Page 12Linked to original sources
PubMed2002

Predictors of mood response to acute tryptophan depletion. A reanalysis.

Acute tryptophan depletion (ATD) induces depressive symptoms in 50-60% of selective serotonin reuptake inhibitor (SSRI) treated, recovered depressed patients. However, no reliable predictors of mood response to ATD have been established. In the present study, individual subject data of six ATD studies were pooled ('mega-analysis') in order to investigate the mediating role of clinical, demographic and biochemical characteristics in the mood response to ATD. A procedure was developed to make different versions of the Hamilton scale comparable. Recurrent depressive episodes, female gender, prior exposure to SSRI antidepressant treatment and previous serious suicidal thoughts/attempts all appear to be independent predictors of mood response to ATD. Chronicity of illness is the most powerful predictor. Residual symptoms of depression were not found to predict response to ATD. ATD may be useful to study the mechanism of action of SSRI antidepressants and individual biological vulnerability of the serotonin system. Whether the effects of ATD represent a reversal of the action of SSRI antidepressants or individual vulnerability probably depends upon the timing of the procedure in the course of remission of a depressive episode.

Adult↗
PubMed2004

"Lipotyphlan" phylogeny based on the growth hormone receptor gene: a reanalysis.

From an evolutionary perspective, "insectivores" have been one of the most important mammalian groups for over a century. Morphologists have successively pruned flying lemurs, elephant shrews, and tree shrews from Insectivora, but have retained chrysochlorids, tenrecs, erinaceids, soricids, talpids, and solenodontids in crown-group Lipotyphla. With the appearance of large molecular data sets, the monophyly of Lipotyphla has proved untenable. Rather, an emerging consensus is that Lipotyphla is a diphyletic taxon comprised of two monophyletic groups, Afrosoricida and Eulipotyphla. A recent paper by Malia et al. [Mol. Phylogenet. Evol. 24 (2002) 91-101] challenged this view and argued that "While the data [Growth Hormone Receptor] were unable to support the orders Lipotyphla, Eulipotyphla, and Tenrecoidea [= Afrosoricida] this was most likely due to the polyphyly of these groups and not to problems associated with the gene itself such as saturation or highly divergent sequences em leader " (p. 100). We analyzed Malia et al.'s original GHR data set (at both nuclear and protein level), an expanded GHR data set that included 49 additional sequences, and a concatenated data set that included GHR, BRCA1, vWF, and A2AB for a diverse selection of lipotyphlan taxa. Although protein analyses proved inconclusive, all analyses at the DNA level clearly show that the statement of Malia et al. is erroneous. Indeed, likelihood analyses with GHR and with the concatenated data set provide more support for Eulipotyphla and Afrosoricida than for competing hypotheses. These results also highlight the potential pitfalls of single-gene and parsimony-only analyses.

Animals↗
PubMed2003

Effect of raloxifene on the risk of new vertebral fracture in postmenopausal women with osteopenia or osteoporosis: a reanalysis of the Multiple Outcomes of Raloxifene Evaluation trial.

Raloxifene reduces vertebral fracture risk in postmenopausal women with osteoporosis and established osteoporosis, but its efficacy in women with osteopenia has not been studied. The objective of this study was to evaluate the effect of raloxifene hydrochloride on the risk of vertebral fractures in postmenopausal women with osteopenia and to compare this effect with that in women with osteoporosis as defined by the bone mineral density (BMD) T-score at the hip. We studied the 3204 postmenopausal women with osteopenia or osteoporosis without vertebral fractures at baseline in the Multiple Outcomes of Raloxifene Evaluation trial. Compared with placebo, 60 mg/day raloxifene reduced the risk of new vertebral fractures at 3 years independent of baseline total hip BMD. The relative risk for new vertebral fractures for the raloxifene group compared with placebo was 0.53 (95% CI, 0.32-0.88) for those with osteopenia and 0.31 (0.06-0.71) for those with osteoporosis. In raloxifene-treated women the rate of vertebral fracture was similar in women with osteoporosis (2%) to that in women with osteopenia (1.9%). For clinically apparent vertebral fractures, the relative risk of fracture in the osteopenia group for raloxifene was 0.25 (0.04-0.63) compared with placebo. There were no new clinical vertebral fractures in women with osteoporosis receiving raloxifene, whereas four occurred in the placebo group. We conclude that treatment with 60 mg/day raloxifene significantly decreases the risk of new vertebral fractures and new clinical vertebral fractures in postmenopausal women without baseline vertebral fracture who have osteopenia or osteoporosis.

Aged↗
PubMed2006

Reanalysis of systematic reviews: the case of invasive strategies for acute coronary syndromes.

OBJECTIVES: The objective of this study was to collect all systematic reviews on invasive strategies for acute coronary syndromes (ACS) and reanalyze the data in these reviews to reach combined estimates, as well as to make predictions on the effectiveness and risk of harm so as to facilitate relevant decision making in health care. METHODS: The data sources used were the following electronic databases, searched from 1994 to September 2004: Cochrane Database of Systematic Reviews; Cochrane Central Register of Controlled Trials; DARE, HTA, EED (NHS CRD); MEDLINE In-Process, Other Non-Indexed Citations, MEDLINE, and PubMed (2000 to 2004). References to the identified systematic reviews were checked. An ancillary search to identify recent randomized controlled trials (RCTs) covering the period from January 2003 to January 2006 was done in MEDLINE(R). We included systematic reviews of RCTs on patients with ACS. In unstable angina and non-ST-elevation myocardial infarction (UA/NSTEMI), eligible reviews had to compare early routine invasive strategy with early selective invasive strategy. In ST-elevation myocardial infarction (STEMI), a comparison between primary percutaneous coronary intervention (PCI) and thrombolytic therapy was required. The methodological quality of the reviews was assessed, and a standardized data extraction form was used. Results for the main outcomes of the RCTs in the reviews were reanalyzed. An additional search of those RCTs not included in the meta-analyses was performed for UA/NSTEMI and short-term morality data on STEMI. Bayesian models were constructed to estimate the uncertainty about a possible treatment effect and to make predictions and probability statements. Main results are based on these analyses. Mortality was considered as the primary outcome measure. RESULTS: One systematic review on invasive strategies was identified for UA/NSTEMI and nine on invasive strategies for STEMI. Five reviews of the latter that were published after the year 2000 were included for the final analysis. The median quality score was 10.5 (range, 7-13; n = 6) on a scale from 0 to 18 points. An updated literature search identified one further RCT on UA/NSTEMI. Regarding NSTEMI and mortality, the average risk difference favoring an early invasive treatment strategy compared with early conservative strategy was .6 percent (95 percent credible interval [CrI], -2.1 to 1.0). Predicted risk (relative risk/risk difference scales) of doing harm was 26.7/26.6 percent. Regarding STEMI and mortality, the absolute risk reduction in favor of primary PCI over thrombolysis was 4.1 percent (95 percent CrI, -7.1 to -1.1) when PCI was compared with streptokinase and 1.2 percent (95 percent CrI, -2.7 to .2) when compared with fibrin-specific thrombolytics. Predicted risk of harm was 8.9/5.3 percent and 8.0/13.3 percent, respectively. CONCLUSIONS: There seems to be at present no solid evidence for survival benefit on early invasive strategy for UA/NSTEMI as a broad diagnostic group, and the risk of doing harm should be considered. Also, the evidence for PCI to decrease early mortality after STEMI is scanty. Estimations of predicted harm may further aid decisions on whether to implement the new treatment over the old one. It may also give an additional dimension for interpreting the results of any meta-analysis.

Angioplasty, Balloon, Coronary↗
PubMed1992

Moving from the question of efficacy to the question of therapeutic relevance: an exploratory reanalysis of a controlled clinical study of 130 inpatients with dementia syndrome taking piracetam.

The authors reanalyzed previously published data from a prospectively randomized, placebo-controlled, double-blind phase-III study of 130 inpatients with dementia syndrome. The patients in the study had been diagnosed as having suffered from organic brain syndrome (ICD 290), which is the core syndrome of dementia (so-called dementia syndrome) for at least two years. They were treated with piracetam for three months at a dose level of 4,800 mg/d. These data were reexamined in order both to survey the extent of drug-related improvement and response rates when assessed at different levels and to investigate the comparability of efficacy in subgroups suffering from either senile dementia of the Alzheimer type or multi-infarct dementia. Three scales were used for the assessment of efficacy. They were the CGI, or Clinical Global Impression, completed by the physicians; the SCAG, or Sandoz Clinical Assessment Geriatric, used by clinical psychologists; and the BGP, or Beurteilungsskala für Geriatrische Patienten (Evaluation Scale for Geriatric Patients), employed by the nursing staff. The Syndrome-Kurztest (SKT) and Benton tests served to measure performance. The items and subscores of the SCAG and the SKT were highly intercorrelated at baseline, forming a common factor fairly independent of the information gained by BGP. This suggests that merely using different kinds of information-gathering methods, i.e., clinical scales and performance tests, completed by different groups of observers, does not automatically result in nonredundant comprehensive information. When using the most conservative response criterion of individual improvement, i.e., at least one baseline standard deviation, treatment with piracetam showed statistically significant (pe less than .001) explorative response rates of 50% and above in three out of four target variables, as compared to the 0 to 6% obtained with placebo. CGI was used as descriptive variable. Again, using this response criterion from a separate analysis of diagnostic subgroups, as matched by the median of the patients' Hachinski Ischemic Scale scores, it does not appear that piracetam's efficacy for patients with senile dementia of the Alzheimer type (SDAT) varies with its efficacy for patients with multi-infarct dementia (MID).

Aged↗
PubMed1998

Acetyl L-carnitine slows decline in younger patients with Alzheimer's disease: a reanalysis of a double-blind, placebo-controlled study using the trilinear approach.

OBJECTIVES: To assess the longitudinal effects of acety-L-carnitine (ALC) on patients diagnosed with Alzheimer's disease. DESIGN: Longitudinal, double-blind, parallel-group, placebo-controlled. SETTING: Twenty-four outpatient sites across the United States. PARTICIPANTS: A total of 334 subjects diagnosed with probable Alzheimer's disease by NINCDS-ADRDA criteria. These data were originally reported by Thal and colleagues (1996). MEASUREMENTS: Cognitive subscale of the Alzheimer Disease Assessment Scale (ADAS) given every 3 months for 1 year. RESULTS: The average rate of change was estimated using the trilinear approach, which allows for periods of both change and stability. Both the ALC group and the placebo group exhibited the same mean rate of change on the ADAS (0.68 points/month). However, a multiple regression analysis revealed a statistically significant Age x Drug interaction characterized by younger subjects benefiting more from ALC, significant, cutpoint for ALC benefit was 61 years of age. CONCLUSIONS: ALC slows the progression of Alzheimer's disease in younger subjects, and the use of the trilinear approach to estimate the average rate of change may prove valuable in pharmacological trials.

Acetylcarnitine↗
PubMed1999

Reanalysis of solute retention on immobilized human serum albumin using fractal geometry.

Earlier experimental data for sucrose dependence of dansyl amino acid retention on immobilized human serum albumin (Peyrin E.; et al. Anal. Chem. 1998, 70, 2812) are reexamined within a fractal framework. A mathematical development based on the fractal geometry of Mandelbrot is proposed to provide a more realistic picture of the molecular association between the ligand and the site II cavity. The fractal dimension D of the cavity surface is calculated using the theoretical approach from previous data. Results show that the surface morphology of the cavity is strongly influenced by the surface tension effects of sucrose molecules, the salting-out agent leveling the surface irregularities. In addition, dansyl amino acid retention and thermodynamic parameter variations are discussed using this fractal concept of surface fluctuations.

Algorithms↗
PubMed1999

Use of different outcome measures in randomised studies of malignant glioma can significantly alter the interpretation of time to progression: reanalysis of the MRC BR2 study.

The Medical Research Council (MRC) BR2 study [1] is a randomised trial of two doses of cranial radiation for patients with malignant glioma. We reanalysed data to examine the effect of using change in ranked scales of neurological status (MRC Neurological Status Scale) and performance (World Health Organisation Scale: WHO) to determine progression rather than clinician's impression. Four hundred and seventy four patients were studied. Where clinicians recorded no progression, ranked scales frequently documented progression (MRC 13%; WHO 13%). Where clinicians recorded progression, ranked scales frequently did not alter (MRC 33%; WHO 30%) or occasionally improved (MRC 5%; WHO 3%). When analysing time to progression based on a variety of measures, the estimated difference between treatments was most extreme (hazard ratio 0.81, logrank p = 0.04) when change in WHO status was used, and least extreme when change in MRC neurological status was used (hazard ratio 0.99, p = 0.94). This study highlights how different outcome measures can significantly alter the interpretation of randomised studies.

Central Nervous System Neoplasms↗
PubMed2004

A reanalysis of protein polymorphism in Drosophila melanogaster, D. simulans, D. sechellia and D. mauritiana: effects of population size and selection.

Comparison of synonymous and nonsynonymous variation/substitution within and between species at individual genes has become a widely used general approach to detect the effect of selection versus drift. The sibling species group comprised of two cosmopolitan (Drosophila melanogaster and Drosophila simulans) and two island (Drosophila mauritiana and Drosophila sechellia) species has become a model system for such studies. In the present study we reanalyzed the pattern of protein variation in these species, and the results were compared against the patterns of nucleotide variation obtained from the literature, mostly available for melanogaster and simulans. We have mainly focused on the contrasting patterns of variation between the cosmopolitan pair. The results can be summarized as follows: (1) As expected the island species D. mauritiana and D. sechellia showed much less variation than the cosmopolitan species D. melanogaster and D. simulans. (2) The chromosome 2 showed significantly less variation than chromosome 3 and X in all four species which may indicate effects of past selective sweeps. (3) In contrast to its overall low variation, D. mauritiana showed highest variation for X-linked loci which may indicate introgression from its sibling, D. simulans. (4) An average population of D. simulans was as heterozygous as that of D. melanogaster (14.4% v.s. 13.9%) but the difference was large and significant when considering only polymorphic loci (37.2% v.s. 26.1%). (5) The species-wise pooled populations of these two species showed similar results (all loci = 18.3% v.s. 20.0%, polymorphic loci = 47.2% v.s. 37.6%). (6) An average population of D. simulans had more low-frequency alleles than D. melanogaster, and the D. simulans alleles were found widely distributed in all populations whereas the D. melanogaster alleles were limited to local populations. As a results of this, pooled populations of D. melanogaster showed more polymorphic loci than those of D. simulans (48.0% v.s. 32.0%) but the difference was reduced when the comparison was made on the basis of an average population (29.1% v.s. 21.4%). (7) While the allele frequency distributions within populations were nonsignificant in both D. melanogaster and D. simulans, melanogaster had fewer than simulans, but more than expected from the neutral theory, low frequency alleles. (8) Diallelic loci with the second allele with a frequency less than 20% had similar frequencies in all four species but those with the second allele with a frequency higher than 20% were limited to only melanogaster the latter group of loci have clinal (latitudinal) patterns of variation indicative of balancing selection. (9) The comparison of D. simulans/D. melanogaster protein variation gave a ratio of 1.04 for all loci and 1.42 for polymorphic loci, against a ratio of approximately 2-fold difference for silent nucleotide sites. This suggests that the species ratios of protein and silent nucleotide polymorphism are too close to call for selective difference between silent and allozyme variation in D. simulans. In conclusion, the contrasting levels of allozyme polymorphism, distribution of rare alleles, number of diallelic loci and the patterns of geographic differentiation between the two species suggest the role of natural selection in D. melanogaster, and of possibly ancient population structure and recent worldwide migration in D. simulans. Population size differences alone are insufficient as an explanation for the patterns of variation between these two species.

Alleles↗
PubMed2001

Anxiety sensitivity, panic, and depressed mood: a reanalysis teasing apart the contributions of the two levels in the hierarchial structure of the Anxiety Sensitivity Index.

Anxiety sensitivity (AS) has been defined as the fear of anxiety and anxiety-related sensations, and evidence suggests that AS plays an important role in the psychopathology of panic. It is entirely unclear whether the relation between AS and panic should be attributed to one (or more) of the AS group factors, the general AS factor, or to factors at both levels of the AS hierarchy. The authors reanalyzed data presented earlier by R. M. Rapee, T. A. Brown, M. A. Antony, and D. H. Barlow (1992) to tease apart the contributions of the different levels of the AS hierarchy to fear responses to hyperventilation and 5.5% carbon dioxide challenges. The results demonstrated that AS-Physical Concerns is the only one of the three AS group factors that contributes to relations with fear responses to these two challenges. However, AS-Mental Incapacitation Concerns had a stronger positive linear association with depressed mood than did AS-Physical Concerns.

Adult↗
PubMed1996

Hypnotic enhancement of cognitive-behavioral weight loss treatments--another meta-reanalysis.

In a 3rd meta-analysis of the effect of adding hypnosis to cognitive-behavioral treatments for weight reduction, additional data were obtained from authors of 2 studies, and computational inaccuracies in both previous meta-analyses were corrected. Averaged across posttreatment and follow-up assessment periods, the mean weight loss was 6.00 lbs. (2.72 kg) without hypnosis and 11.83 lbs. (5.37 kg) with hypnosis. The mean effect size of this difference was 0.66 SD. At the last assessment period, the mean weight loss was 6.03 lbs. (2.74 kg) without hypnosis and 14.88 lbs. (6.75 kg) with hypnosis. The effect size for this difference was 0.98 SD. Correlational analyses indicated that the benefits of hypnosis increased substantially over time (r = .74).

Cognitive Behavioral Therapy↗
PubMed2000

The effects of learning a new algorithm on asymptotic accuracy and execution speed in old age: a reanalysis.

Time-accuracy curves were derived for 16 younger and 19 older persons who participated in a study on training in the method of loci (Baltes & Kliegl, 1992). The effects of instruction were to immediately and permanently boost asymptotic performance and initially slow down the rate of approach to the asymptote. After extensive practice, rate of approach returned to the initial fast level. Age differences were found in both asymptotic performance and rate of approach. The effects of instruction and practice, however, were similar in younger and older adults, but older adults needed 1 session of instruction more than younger adults did before the intervention showed its full effect.

Adult↗