Selection of task-dependent diffusion filters for the post-processing of SPECT images

Iterative reconstruction from single photon emission computed tomography (SPECT) data requires regularization to avoid noise amplification and edge artefacts in the reconstructed image. This is often accomplished by stopping the iteration process at a relatively low number of iterations or by post-filtering the reconstructed image. The aim of this paper is to develop a method to automatically select an optimal combination of stopping iteration number and filters for a particular imaging situation. To this end different error measures between the distribution of a phantom and a corresponding filtered SPECT image are minimized for different iteration numbers. As a study example, simulated data representing a brain study are used. For post-reconstruction filtering, the performance of 3D linear diffusion (Gaussian filtering) and edge preserving 3D nonlinear diffusion (Catté scheme) is investigated. For reconstruction methods which model the image formation process accurately, error measures between the phantom and the filtered reconstruction are significantly reduced by performing a high number of iterations followed by optimal filtering compared with stopping the iterative process early. Furthermore, this error reduction can be obtained over a wide range of iteration numbers. Only a negligibly small additional reduction of the errors is obtained by including spatial variance in the filter kernel. Compared with Gaussian filtering, Catté diffusion can further reduce the error in some cases. For the examples considered, using accurate image formation models during iterative reconstruction is far more important than the choice of the filter.     

Mental disorders in elderly suicide

The purpose of this study was to investigate the prevalence and comorbidity of current mental disorders defined by DSM-III-R among elderly suicide victims and to compare them with the mental disorders among younger victims. Using a psychological autopsy method, we collected comprehensive data on all suicides in Finland during 1 year. Retrospective Axis I-III consensus diagnoses were assigned to a random sample consisting of 43 victims aged 60 years or over and 186 victims aged under 60 from the nationwide suicide population. At least one Axis I diagnosis was made for 91% of the elderly victims. Major depression as the principal diagnosis was more common among the elderly victims. Almost all elderly female victims were major depressives. Psychiatric comorbidity was more common among elderly male than among elderly female victims. More of the elderly victims (88%) than the younger (36%) received Axis III diagnoses. Suicide among the elderly without a diagnosable mental disorder and somatopsychiatric comorbidity seems to be rare.     

Study of the phlebotomines (Diptera, Psychodidae), in area of cutaneous leishmaniasis in the State of Mato Grosso do Sul, Brazil

Interleukin-1 beta (IL-1 beta) significantly inhibits insulin secretion from glucose stimulated islet cells. The mechanism for this inhibition has been hypothesized to be due to stimulation of the inducible form of nitric oxide synthase and a resulting increase in nitric oxide (NO) concentration. Ways to block the effect of IL-1 beta have focused on blocking the binding of IL-1 beta to the IL-1 receptor and the use of antioxidants to neutralize increases in NO. This report focuses on a 33 residue peptide synthesized based on the C-terminal region of the IL-1 beta molecule, a reported binding site of the IL-1 beta molecule, and the redoxcycling antioxidant pyrroloquinoline quinone (PQQ). The 33 residue peptide did not function as an antagonist, but as a weak agonist. High concentrations of PQQ itself inhibited glucose-dependent insulin release while low concentrations did not. PQQ had no effect on the actions of IL-1 beta. Three isosteric and isomeric analogues of PQQ were also investigated. One of the PQQ isomers had an inhibitory effect on insulin secretion at low concentrations where PQQ had no effect. These results reflect the sensitivity of islets to oxidative stress.     

Bovine mastitis due to algae of the genus Prototheca

A survey of the prevention of disability policy and activities in a random sample of 200 ILEP assisted projects was conducted in 1995. This was followed by a workshop of field experts in different aspects of prevention of disability who work in different geographical regions. The survey findings and state of current knowledge on prevention of disability were reviewed during the workshop and recommendations on the planning, implementation, and evaluation of simple and effective prevention of disability developed. Prevention of disability includes complex activities, such as nerve decompression and reconstructive surgery, however these recommendations focus on the simple techniques and approaches which can be implemented through leprosy control programmes, primary health care and community-based rehabilitation. These recommendations have been approved by the ILEP Medical Commission, and reported in the ILEP Medical Bulletin (N degree 8, December 1995).     

Tetanus--the silent killer: how safe are you?

Despite the fact that tetanus is entirely preventable, mortality and morbidity as a result of this disease remain significant. The tetanus toxoid is one of the most potent poisons known. While immunisation programs focus on children, the elderly remain at risk of contracting immunisable diseases. Tetanus often leads to prolonged hospital stays and requires emergency and intensive care intervention and management. This case study illustrates a number of important points concerning the recognition, treatment, management and prevention of tetanus poisoning, and highlights the importance of considering the immunisation status of our elderly patients.     

Effects of cognitive style and counselor–client compatibility on client growth.

Tests of 2 cognitive style dimensions (serialism–holism and field dependence–independence; measured by the Gandlemuller Test and the Group Embedded Figures Test, respectively) were administered to 60 counselor trainees in graduate clinical and counseling psychology programs and 60 volunteer clients drawn from a university-level applied psychology course. 32 counselor–client pairs matched or mismatched on the 2 dimensions were formed. Counselor and client pairs engaged in 2 50-min therapy sessions that focused on client self-enhancement. In independent rating sessions, matching effects for field dependence–independence were obtained in clients' subjective ratings of improvement in self-exploration skills and in clients' and counselors' subjective ratings of the ease of relating with each other. Implications and applications for achieving maximum counselor–client compatibility in a person–environment interaction model are discussed. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Maximal functional capacity in patients with endomyocardial fibrosis

We evaluated objectively the cardiocirculatory dysfunction of patients with EMF, and related the functional class (FC-NYHA) to the data obtained by analysis of maximal functional capacity. We studied 55 subjects, divided into three groups: group 1 (G1) 21 (38.1%) normal persons, group 2 (G2) seven (12.7%) patients with EMF who were in FC I or II, and group 3 (G3) 27 (49%) patients in FC III or IV. Maximal oxygen consumption (VO2max) and O2 pulse index (PO2max) were obtained using a Beckman computerized gas analyser. The mean values were significantly different among the three groups. We conclude that the greater the clinical impairment, the greater the alterations that occur in the indices of cardiac function.     

Farewell from the editor.

As I put the final touches on the contents of the Canadian Journal of Behavioural Science for October 1993 (No. 4 of Volume 25), it has come to my attention that this is the last issue that will be published under my Editorship. I want to take this opportunity to express my appreciation to numerous people who have made important contributions to the quality of the Journal, and specifically to Volumes 22, 23, 24 and 25 which were published under my Editorship. (PsycINFO Database Record (c) 2010 APA, all rights reserved)