Erasmus Wilson - philanthropic polymath: an enigmatic personality.
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Charities↗
Biomedical subjects
S Gold
Publications and source records attributed to S Gold.
Functional MRI statistical software packages: a comparative analysis.
Currently, there are many choices of software packages for the analysis of fMRI data, each offering many options. Since no one package can meet the needs of all fMRI laboratories, it is helpful to know what each package offers. Several software programs were evaluated for comparison of their documentation, ease of learning and use, referencing, data input steps required, types of statistical methods offered, and output choices. The functionality of each package was detailed and discussed. AFNI 2.01, SPM96, Stimulate 5.0, MEDIMAX 2.01, and FIT were tested. FIASCO, Yale, and MEDx 2.0 were described but not tested. A description of each package is provided.
Algorithms↗
Revision of dementia guidelines.
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Dementia↗
A method to determine activation thresholds in fMRI paradigms.
Determining meaningful activation thresholds in functional magnetic resonance imaging (fMRI) paradigms is complicated by several factors. These include the time-series nature of the data, the influence of physiological rhythms (e.g. respiration) and vacillations introduced by the experimental design (e.g. cueing). We present an empirical threshold for each subject and each fMRI experiment that takes these factors into account. The method requires an additional fMRI data set as similar to the experimental paradigm as possible without dichotomously varying the experimental task of interest. A letter fluency task was used to illustrate this method. This technique differs from classical methods since the Pearson correlation probability values tabulated from statistical theory are not used. Rather each subject defines his or her own set of threshold probability values for correlations. It is against these empirical thresholds, not Pearson's, that an experimental fMRI correlation is assessed.
Adult↗
Factors that influence effect size in 15O PET studies: a meta-analytic review.
The PET literature is growing exponentially, creating a need and an opportunity to perform a meta-analytic review consolidating the published information. This study describes the use of effect size as an index in PET studies and discusses how this measure can be used for comparing findings across studies, laboratories, and paradigms. In comparing studies across laboratories it is essential to know how the methods employed affect the results and conclusions drawn. This study also compared effect size for two different methods of tracer delivery in 15O PET studies ([15O]H2O bolus injection versus inhalation of [15O]CO2), whether averaged versus single-scan conditions were used, and the data analytic strategy employed. The effect sizes observed across studies were consistently large with a median effect size of 8.55, indicating that the phenomena investigated in 15O PET studies are strong. The largest peak activation reported in a study was found to be affected by variability in sample size, data analytic strategy, and repeat versus single-scan conditions. However, the impact of these factors was not examined on smaller or less intense peaks. Minimal standards for reporting statistical results are discussed.
Data Interpretation, Statistical↗
A geriatric consultation team in the emergency department.
BACKGROUND: The proportion and absolute number of older patients presenting to emergency departments (EDs) are increasing. Older ED patients tend to have multiple medical and psychosocial problems that make their care in the ED problematic. Despite this, there have been no previous descriptions of geriatric ED consultative services. SETTING: The Sir Mortimer B. Davis Jewish General Hospital is a 628-bed tertiary care McGill University teaching hospital. It serves a population of about 160,000, of which 23% are aged 65 and older. In response to the special needs of this group, the Division of Geriatric Medicine at the Jewish General Hospital has developed, among its clinical and teaching services, an ED consultation team. PROGRAM DESCRIPTION: The consultation team is composed of a geriatrician, a full-time nurse clinician, and part-time physical and occupational therapists. Consultations are received from referring, primarily Ed physicians and encompass all aspects of medical and psychosocial issues. Geriatric assessment is geared toward decision making for rapid disposition: discharge home or admission to acute geriatrics ward or other services. Thus, the service functions as a gatekeeper for admission to the acute geriatrics ward, as well as coordinating geriatric follow-up both in-hospital (for patients admitted to other services) and in the community (for patients discharged home), via the outpatient geriatric clinic, home visits, or linkage to other community resources.
Aged↗
Timed-sequential induction therapy improves postremission outcome in acute myeloid leukemia: a report from the Children's Cancer Group.
Timed sequencing of cycles of induction chemotherapy in acute myeloid leukemia (AML) has been proposed as a way to achieve maximal leukemic cell kill through recruitment and synchronization of residual neoplastic cells. Furthermore, whether intensive induction therapy should be continued in the presence of profound myelosuppression is an important question. The Children's Cancer Group (CCG) conducted a prospective randomized trial in which 589 patients with AML were randomized at diagnosis to one of two induction approaches involving a 4-day cycle of five active chemotherapeutic agents, with the second cycle administered either 10 days after the first cycle, despite low or dropping blood counts (intensive timing), or 14 days or later from the beginning of the first cycle, depending on bone marrow status (standard timing). All patients achieving remission received a total of four cycles of induction therapy. They were then allocated to allogeneic bone marrow transplantation (BMT) if a compatible family donor was present or randomized to aggressive nonmyeloablative therapy or to myeloablative therapy with purged autologous BMT rescue. The three postremission arms remain coded. Induction success and median days to complete induction were similar for the 295 patients randomized to the intensive timing arm (75%, 99 days) compared with the 294 patients randomized to the standard timing arm (70%, 105 days; P = .18 for remission). However, a marked improvement in outcome was demonstrated in patients randomized to the intensive timing arm, with an actuarial event-free survival at 3 years of 42% +/- 7% (95% confidence interval [CI]) versus 27% +/- 6% for patients on the standard timing arm (P = .0005). Disease-free survival results at 3 years from the end of induction were superior for patients receiving intensively timed induction therapy (N = 211), 55% +/- 9% versus 37% +/- 9% for standard timing patients (N = 195, P = .0002), with a median follow-up from achieving remission of 28 months. Superior results were documented for patients receiving intensive timing irrespective of the postremission therapy to which they were allocated. Intensively timed induction therapy for patients with AML markedly improves event-free survival, even for patients undergoing myeloablative therapy with BMT rescue. Without controlling for the type of induction therapy received, results of various BMT studies in AML comparing different preparative regimens will be difficult to interpret.
Acute Disease↗
Normalizing counts and cerebral blood flow intensity in functional imaging studies of the human brain.
Image intensity normalization is frequently applied to eliminate or adjust for subject or injection global blood flow (gCBF) and other sources of nuisance variation. Normalization has several other positive effects on the analysis of PET images. However, the choice of an intensity normalization technique affects the statistical and psychometric properties of the image data. We compared three normalization procedures, the ratio approach (regional (r)CBF/gCBF), histogram equalization, and ANCOVA, on both PET count and flow data sets. The ratio method presents the proportional increase of regions, the histogram equalization method offers the relative ranking of intensities over the image, and the ANCOVA method provides statistical deviations from an expected linear model of regional values from the subject's gCBF. The original study used 33 normal subjects in a standard subtraction paradigm. The normalization methods were evaluated on their ability to remove extraneous error variation, induce homogeneity of intersubject variation, and remove unwanted dependencies. In general, the normalization modified the subtraction image more than the individual condition images. All three methods worked well at removing the dependency of rCBF on gCBF in count and flow images. For count data, the three methods also reduced the amount of error variation equally well, improving the signal to noise ratio. For flow data, the histogram equalization and ratio methods worked best at reducing statistical error. All three methods dramatically stabilized the variance over the image.
Analysis of Variance↗
Tests for comparing images based on randomization and permutation methods.
Tests comparing image sets can play a critical role in PET research, providing a yes-no answer to the question "Are two image sets different?" The statistical goal is to determine how often observed differences would occur by chance alone. We examined randomization methods to provide several omnibus test for PET images and compared these tests with two currently used methods. In the first series of analyses, normally distributed image data were simulated fulfilling the requirements of standard statistical tests. These analyses generated power estimates and compared the various test statistics under optimal conditions. Varying whether the standard deviations were local or pooled estimates provided an assessment of a distinguishing feature between the SPM and Montreal methods. In a second series of analyses, we more closely simulated current PET acquisition and analysis techniques. Finally, PET images from normal subjects were used as an example of randomization. Randomization proved to be a highly flexible and powerful statistical procedure. Furthermore, the randomization test does not require extensive and unrealistic statistical assumptions made by standard procedures currently in use.
Computer Simulation↗
cAMP regulates morphogenesis in the fungal pathogen Ustilago maydis.
The fungal pathogen Ustilago maydis exhibits a dimorphic switch from budding to filamentous growth in response to mating interactions and environmental conditions. We have found that disruption of the uac1 gene, encoding adenylate cyclase, results in a constitutively filamentous phenotype. Budding is restored to the uac1 mutant upon growth in the presence of cAMP or by extragenic suppression because of a mutation in the ubc1 gene. The ubc1 gene encodes a type II regulatory subunit of cAMP-dependent protein kinase (PKA); defects in this gene attenuate the filamentous growth that normally occurs in response to mating and exposure to air. Growth of wild-type cells in cAMP and mutation of the ubc1 gene also cause defects in the separation of mother and daughter cells (cytokinesis) and alter bud site selection. These results indicate a key role for cAMP and PKA in morphogenesis in U. maydis; this role may be common among dimorphic fungal pathogens.
Adenylyl Cyclases↗
Exposure of simian virus-40-transformed human cells to magnetic fields results in increased levels of T-antigen mRNA and protein.
In its integrated form. SV-40 DNA offers an opportunity to observe the behavior of what is in effect a viral genome within a cellular genome, with transcriptional and translational products that can be clearly distinguished from those of the host cell. Exposure of SV40-transformed human fibroblasts to a 60 Hz continuous-wave sinusoidal electromagnetic (EM) field resulted in increased levels of virally derived mRNA and protein of large T-antigen. These findings provide evidence that a foreign DNA integrated into cells can be affected by EM fields under conditions known to cause increased transcripts from endogenous cellular genes.
Antigens, Viral, Tumor↗
Re: Current status of lasers in soft tissue dental surgery (J Periodontol; 1993; 64:589-602)
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Carbon Dioxide↗
Behavioral adaptation to human immunodeficiency virus-seropositive status in children and adolescents with hemophilia.
OBJECTIVE: To examine the behavioral adaptation to human immunodeficiency virus (HIV)-seropositive status, as defined by parental report, in children and adolescents with hemophilia. RESEARCH DESIGN: A clinical descriptive study of two groups of patients as part of a longitudinal design. SETTING: A university-based comprehensive hemophilia center and department of neurology acquired immunodeficiency syndrome dementia center. PATIENTS: Forty-six male children with hemophilia divided into two groups based on HIV-seropositive (n = 18) or -seronegative (n = 28) status. None of the patients were symptomatic for acquired immunodeficiency syndrome. SELECTION PROCEDURES: All pediatric patients with documented factor VII or IX deficiency aged between 4 and 19 years at study onset and their families were eligible to participate. All subjects were recruited without regard to human immunodeficiency virus status. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Profiles of behavioral adjustment were obtained from parents' reports on the Child Behavior Checklist for the HIV-seropositive and HIV-seronegative groups. The two groups did not differ on any of the major indexes of the Child Behavior Checklist, even after adjusting for maternal education and severity of hemophilia. There also was no difference between the groups when individual cases were examined for the number of child behavior checklist scales falling within a clinically significant range. CONCLUSIONS: The current findings fail to confirm any clear evidence of behavioral problems in an asymptomatic group of HIV-seropositive children and adolescents with hemophilia.
Adaptation, Psychological↗
Auditory event related potentials in chronic tinnitus patients with noise induced hearing loss.
In order to explore a possible deficit in auditory central neural activity in tinnitus with noise induced hearing loss (NIHL), auditory event related potentials (ERP) and reaction time (RT) were recorded (measures of central processing) from tinnitus patients (N = 12) and hearing and age matched controls (N = 12). Testing procedure included oddball paradigms and 1 KHz repetitive stimulus, as well as click-induced brainstem auditory evoked potentials (BAEP). ERP amplitudes (waves N1, P2 and P3) in tinnitus patients were significantly lower than in controls in all testing paradigms. No differences were found in ERP peak latencies, BAEP, RT, or response scoring. The lower ERP amplitudes may indicate attenuated or 'abnormal' auditory central processing in NIHL tinnitus patients. It is suggested that this dysfunction reflects an adaptive brain process response to the tinnitus and points to auditory central involvement in tinnitus sensation.
Acoustic Stimulation↗
Vietnamese refugees and blocked mobility.
"This paper examines data from published sources and ethnographic studies conducted by the authors in Oakland, California and Philadelphia [Pennsylvania] to assess the economic situation of Vietnamese refugees in the United States. Evidence suggests that in strong contrast to being a 'success story,' the economic status of many recently arrived Vietnamese refugees is characterized by unstable, minimum-wage employment, welfare dependency and participation in the informal economy. The paper suggests that the group's economic opportunities have been limited by the configuration of circumstances that have surrounded their entry and settlement into the United States as refugees, as well as by the demographic structure of the group."
Americas↗
Ascorbic acid supplements and blood pressure. A four-week pilot study.
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Administration, Oral↗