Strong anisotropy of projected 3d moments in epitaxial CrO2 films

Soft x-ray magnetic circular dichroism (XMCD) spectra have been investigated for different crystallographic projections of CrO2. Strong anisotropic orbital Cr 3d contributions and a change of sign of the XMCD signal is observed and attributed to t(2g) majority states near the Fermi level. Additionally, moment analysis exhibits anisotropic behavior in the projected spin contributions of CrO2 assigned to a strong magnetic dipole term T(z), consistent with an intrinsic magnetic easy axis behavior along the CrO2 [001] axis. A reduced projected isotropic Cr 3d spin moment has been interpreted in terms of hybridization with oxygen.

HoFe - Garnet soft XMCD measurements below and above the compensation temperature

We have investigated the magnetism of Holmium-Iron-Garnet (Ho3Fe5O12) at the Ho M4,5 - the Fe L2,3 - and the O K - edges. As expected switching of the sub-lattice magnetization is observed at the compensation temperature. We will give detailed analysis ofthe Ho and Fe XMCD signals, using sum rules. Fe dichroism is analyzed in terms of 3d ground state moments and compared to Gadolinium-Iron-Garnet (Gd3Fe5O12). Contributions of octahedral and tetrahedral Fe sites could be separated and analyzed quantitatively. At the oxygen K edge two different structures are observable. Those structures show different temperature dependencies. Therefore we address these features separately to Fe and Rare Earth contributions.

Non-symmetric influences in the total electron yield X-ray magnetic circular dichroism signal in applied magnetic fields

The total electron yield current is strongly influenced by external magnetic fields. As known before, this side effect can be slightly reduced by applied external bias voltages increasing the total sample drain current nearly up to saturation. Nevertheless those effects are not perfectly reduced in almost all X-ray Magnetic Circular Dichroism (XMCD) applications and are more prominent in very small XMCD signals, like O K edge spectra. We show that asymmetries in the total electron yield field response will result in XMCD offset signals, which are strongly photon energydependent and follow the nonmagnetic absorption signal. A simple but effective method to prevent those offset signals, is the use of asymmetric magnetic fields. A quantitative analysis and a numerical reduction method for those offset signals are shown.

Recommendations of the Canadian Consensus Conference on Dementia--dissemination, implementation, and evaluation of impact

BACKGROUND

Subsequent to the development of consensus statements on a clinical topic, it is vital to establish a plan for dissemination, implementation and evaluation of impact. Consensus statements can be used for both guiding continuing medical education (CME) and producing clinical practice guidelines (CPGs). Insufficient attention to dissemination can lead to a failure to change physician behaviour and improve patient outcomes.

METHODS

A plan to disseminate the conclusions of the Canadian Consensus Conference on Dementia (CCCD) was developed. This plan was based on a literature review of CME and CPGs. A Medline search was performed on the dissemination and evaluation of the 1989 Canadian Consensus Conference on the Assessment of Dementia (CCCAD) and other published guides for physicians on dementia care. CCCD dissemination that has occurred to date (June, 2000) was reviewed in this paper.

RESULTS

Lectures and unsolicited printed material are weak forms of CME. Small-group interactive CME that provides practice opportunities appears to be the most effective way to change physician behaviour. The ability of CPGs to change physician behaviour is uncertain. It appears that inadequate attention has been placed on CPG dissemination and implementation. The CCCAD had a modest impact on clinical practice in Canada. While dissemination of the conclusions of the CCCD has taken place, evaluation of the impact of the CCCD has yet to be done. Local initiatives utilizing the conclusions of the CCCD are on-going.

CONCLUSIONS

Further work is needed on how to optimize the impact of consensus statements and CPGs. While dissemination of the CCCD has occurred, it is currently unknown whether it has led to any change in physician practices.

A comparison of allogeneic bone marrow transplantation, autologous bone marrow transplantation, and aggressive chemotherapy in children with acute myeloid leukemia in remission

Intensive, myelosuppressive therapy is necessary to maximize outcomes for patients with acute myeloid leukemia (AML). A comparison was made of 3 aggressive postremission approaches for children and adolescents with AML in a randomized trial, CCG-2891. A total of 652 children and adolescents with AML who achieved remission on 2 induction regimens using identical drugs and doses (standard and intensive timing) were eligible for allocation to allogeneic bone marrow transplantation (BMT) based on matched related donor status (n = 181) or randomization to autologous BMT (n = 177) or to aggressive high-dose cytarabine-based chemotherapy (n = 179). Only 115 patients (18%) refused to participate in the postremission phase of this study. Overall compliance with the 3 allocated regimens was 90%. At 8 years actuarial, 54% +/- 4% (95% confidence interval) of all remission patients remain alive. Survival by assigned regimen ("intent to treat") is as follows: allogeneic BMT, 60% +/- 9%; autologous BMT, 48% +/- 8%; and chemotherapy, 53% +/- 8%. Survival in the allogeneic BMT group is significantly superior to autologous BMT (P =.002) and chemotherapy (P =.05); differences between chemotherapy and autologous BMT are not significant (P =.21). No potential confounding factors affected results. Patients receiving intensive-timing induction therapy had superior long-term survival irrespective of postremission regimen received (allogeneic BMT, 70% +/- 9%; autologous BMT, 54% +/- 9%; chemotherapy, 57% +/- 10%). Allogeneic BMT remains the treatment of choice for children and adolescents with AML in remission, when a matched related donor is available. For all others, there is no advantage to autologous BMT; hence, aggressive nonablative chemotherapy should be used.

Visualization of subthalamic nuclei with cortex attenuated inversion recovery MR imaging

There is a significant amount of interest in studying the thalamus because of its central location in the brain and its role as a gatekeeper to higher centers of cognition. Imaging and measuring of the individual subnuclei of the thalamus has proven extremely difficult in MR because of the contrast-to-noise (CNR) of the MR sequences used. This report describes a novel MR pulse sequence known as cortex attenuated inversion recovery (CAIR), which increases the CNR in images and allows the individual subnuclei of the thalamus to be visualized by selectively nulling the gray matter in the brain using an inversion recovery sequence with an inversion time of 700 ms at 1.5 T.

Longitudinal study of cognitive function in first-episode and recent-onset schizophrenia

OBJECTIVE

Whether cognitive function in schizophrenia deteriorates, improves, or remains stable is a crucial question. Few studies have examined the longitudinal stability of cognitive function and the relationship between cognitive performance and clinical symptoms over time in a cohort of well-treated patients with schizophrenia.

METHOD

In the present study, 54 patients with first-episode and recent-onset schizophrenia completed a comprehensive cognitive test battery and were rated on symptom measures at index hospitalization and again after 5 years.

RESULTS

Performance IQ and full-scale IQ significantly improved, whereas verbal IQ did not change. Group performance improved on some of the neuropsychological tests, including the Circle A letter-cancellation task, free recall of logical memory test score, and the Wisconsin Card Sorting Test. Mean finger-tapping performance worsened over time, whereas performance on other neuropsychological tests did not change. Negative, psychotic, and disorganized symptoms significantly improved over the time period. Changes in negative symptoms were correlated with performance changes in verbal IQ and full-scale IQ but not performance IQ. Improvement in verbal cognition was observed when negative symptoms improved. Psychotic and disorganized symptom dimensions were not correlated with any IQ measure.

CONCLUSIONS

These results indicate that in a cohort of young patients receiving neuroleptic treatment early in their illness, cognitive performance does not deteriorate--and may improve. Only one of the three symptom dimensions--negative--was associated with change in cognitive performance. This study supports the view that negative symptoms are associated with a poor long-term cognitive outcome and may be closely related to the primary cognitive deficit in schizophrenia.

Supreme Court to rule on rights of people with disabilities

Since Congress enacted the Americans with Disabilities Act (ADA) in 1990, people with disabilities have demanded nationwide, "Enforce our civil rights," and "Our homes, not nursing homes." Now, in the case Olmstead v. L.C., the United States Supreme Court will decide whether the ADA will be a "civil rights statute" that enforces the rights of the disabled community and a means to achieve homebased services.

Magnetic resonance imaging of neuroblastoma using current techniques

We evaluated the ability of current magnetic resonance (MR) scanning techniques to detect and stage neuroblastoma in children, using surgical and histopathologic correlation. We prospectively and retrospectively reviewed 16 MR examinations from 14 patients with neuroblastoma (13 patients) or ganglioneuroblastoma (1 patient) and compared these to computed tomography (CT) (5 patients) and pathology (all patients). Sequences included: precontrast T1-weighted and T2-weighted images, and gadolinium-enhanced T1-weighted images. The study time for each MR exam was also calculated. Five primary tumors were intrathoracic paraspinous masses, eight were adrenal, and 1 was presacral. Neural foraminal invasion was demonstrated on MR in four of 14 patients. Three of the four patients had undergone CT and neural foraminal invasion was shown in one. Vascular encasement was demonstrated in five of 14 patients on MR images. Three of the five patients had undergone CT and vascular involvement was shown in two. All cases of neural foramina invasion and vascular encasement were proven at surgery. There were no false positive or false negative MR studies of neural foraminal invasion or vascular encasement. Bone marrow invasion was shown in two of 14 patients on MR images which were confirmed by bone marrow aspirate. No false negative cases of bone marrow invasion was shown. In one patient, CT considered one neuroblastoma to be adrenal in location which was correctly shown to be intrathoracic on MR. The mean study time for MR imaging was 49 min. Current MR techniques are accurate at detecting and staging neuroblastoma, and coverage of chest, abdomen, and pelvis can be performed in less than one hour.

Prevalence of potentially reversible dementias and actual reversibility in a memory clinic cohort

BACKGROUND

Although clinics for the evaluation of cognitive dysfunction have typically emphasized the detection and treatment of the reversible causes of dementia, it remains unclear whether the treatment of such causes results in reversal of the dementia. Therefore, the appropriate work-up for dementia is in dispute.

METHODS

A chart review was performed with records from an urban tertiary care referral-based memory clinic. The records for 196 patients with dementia or suspected dementia, seen between October 1991 and December 1993, were examined to determine the prevalence of potentially reversible dementias and whether the cognitive dysfunction improved or resolved after treatment. Data abstracted from the medical charts included demographic information, medication use, presence of depression, and results of neuropsychological tests, blood work and neuroimaging. The clinical diagnosis, the response to treatment, if applicable, and the outcome (mean follow-up period 16 months) were analysed. The recommendations of the 1989 Canadian Consensus Conference on the Assessment of Dementia (CCCAD) on the use of CT were retrospectively applied in each case.

RESULTS

Of the 196 patients, 45 (23.0%) had a potentially reversible condition identified by history, physical examination, blood testing or CT; in only 7 (3.6% of the total) did treatment result in improvement or resolution of the dementia. These 7 patients had higher results for the Mini-Mental State examination (mean result 26) and exhibited only mild cognitive deficits. Potentially reversible lesions were found in the CT scans of 6 (3.1%) patients: 4 had normal-pressure hydrocephalus and 2 had a brain tumour. If the CCCAD recommendations had been followed, CT would have been performed in 76 (38.8%) of the patients, and 1 of the 6 patients with a lesion would have been missed.

INTERPRETATION

Both potential and actual reversibility of dementia was low in these memory clinic patients. The patients whose condition improved with intervention had early and milder cognitive deficits, which suggests that thorough evaluation of early memory loss is warranted.

[Implementation and evaluation of an ambulatory exercise therapy based rehabilitation program for breast cancer patients]

Physical exercise does not only have positive effects on physical fitness but also on mental health. However, there has been little empirical study on effects of rehabilitation programmes based on physical exercise in cancer patients. We conducted a study to examine the interrelation between the participation of breast cancer patients in an exercise rehabilitation training and aspects of quality of life and physical fitness. 28 patients with not metastasized mamma carcinoma participated in a structured exercise rehabilitation program twice a week for ten weeks. Before and after the intervention the patients were asked to fill in questionnaires to assess their quality of life. At the same instants they underwent physical examination and a bicycle ergometry as well as a blood drawing. The training was aimed at changes at the social, emotional, as well as the motor physical level. Pre-post comparisons demonstrated an improvement in quality of life, such as decreased levels of depression and anxiety. Furthermore the women proved to show an obvious increase in physical fitness. Present results support an implementation of an exercise rehabilitation training for breast cancer outpatients.

Toxicity, pharmacology and feasibility of administration of PEG-L-asparaginase as consolidation therapy in patients undergoing bone marrow transplantation for acute lymphoblastic leukemia

We attempted to administer PEG-L-asparaginase (PEG-L-A) following hematologic recovery to 38 patients undergoing autologous or allogeneic marrow transplantation for acute lymphoblastic leukemia (ALL). Twenty-four patients (12 of 22 receiving allogeneic and 12 of 16 receiving autologous transplants) received between one and 12 doses of PEG-L-A, including nine who completed the planned 12 doses of therapy. The toxicities encountered were similar to those observed in non-transplanted patients undergoing therapy with PEG-L-A and included allergic reactions, pancreatitis, weight loss, hypoalbuminemia, and low levels of anti-thrombin III. Of the 24 who received the drug, eight remain in remission. Of 12 patients in second remission at the time of transplantation who received PEG-L-A, five of seven who received allogeneic and two of five who received autologous transplants remain in remission, 16+ to 46+ months from transplant. While PEG-L-A could be administered to most of the patients undergoing marrow transplantation for ALL, most patients either relapsed while receiving the drug or developed toxicities which resulted in abbreviated courses. At this time, we cannot recommend PEG-L-A as single agent, post-BMT chemotherapy.

Distinctive demography, biology, and outcome of acute myeloid leukemia and myelodysplastic syndrome in children with Down syndrome: Children's Cancer Group Studies 2861 and 2891

In recent pediatric trials of acute myeloid leukemia (AML), children with Down syndrome (DS) have had significantly more megakaryoblastic leukemia and have experienced better outcome than other children. To further characterize AML in DS, Children's Cancer Group Studies 2861 and 2891 prospectively studied demography, biology, and response in AML and myelodysplastic syndrome (MDS) of children with and without DS. These studies evaluated timing of induction therapy and compared postremission chemotherapy with marrow transplantation in 1,206 children. One-hundred eighteen (9.8%) had DS, a fourfold increase in 20 years. DS patients were younger, had lower white blood cell and platelet counts, more antecedent MDS, acute megakaryoblastic leukemia or undifferentiated AML, and an under-representation of chromosomal translocations (P < .001 for each variable). Four-year event-free survival in DS was 69% versus 35% in others (P < .001). Intensively timed induction conferred significantly higher mortality in DS patients; bone marrow transplantation offered no advantage. Conventional induction followed by chemotherapy achieved an 88%, 4-year, disease-free survival in DS patients versus 42% in others (P < .001). Megakaryoblastic leukemia was unfavorable in others but prognostically neutral in DS. AML in DS is demographically and biologically distinct from AML in other children. It is singularly responsive to conventional chemotherapy and may warrant even less therapy. The increasing proportion of DS patients with AML most likely reflects changes in attitudes about entering DS patients on AML trials and possibly increasing ability to distinguish megakaryoblastic leukemia from lymphoid leukemia.

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.

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.

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.

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.

Community-Based Educational Programs for Cancer Nursing

A United Way grant allowed the Department of Nursing Research and Education to make available its expertise in cancer nursing and establish itself as a resource for oncology. Community educational needs were assessed by a questionnaire sent to outside agencies prior to designing an oncology educational program. In a 9-month period, 57 classes at 21 different facilities representing 417 hours of instruction were provided. Nurses attending the classes totaled 1,175. Results showed an increase in scores from pre-test to post-test, indicating that participants demonstrated increased knowledge as a result of class participation. This funding provided the catalyst to prepare a large number of community hospital nurses in the complex care of oncology patients.