L-Dopa-responsive Parkinson's syndrome in association with phenylketonuria: In vivo dopamine transporter and D2 receptor findings.

Reports of parkinsonism in phenylketonuria are exceedingly rare. We report on a patient who had received a delayed diagnosis of phenylketonuria as an infant and subsequently developed levodopa-responsive parkinsonism at the age of 33. Single-photon emission computed tomography (SPECT) using (123)I-FP-CIT ([(123))I]-2 beta-carbomethoxy-3beta-(-4-iodophenyl)-N-(3-fluoropropyl)-nortropane) used to measure dopamine transporter levels on two occasions, 7 and 9 years after the onset of neurological symptoms, were normal. Iodine-123-iodo-lisuride SPECT (IBZM) imaging, however, showed reduced caudate over putamen binding. This combination of imaging findings indicates a possible upregulation of postsynaptic D2 receptors in the context of intact presynaptic dopamine nerve terminal density.     

Germline mutations in the neurofibromatosis type 2 tumour suppressor gene

The recent identification of the NF2 tumour suppressor genehas enabled large scale screening for pathological mutationsin the gene. We have sought germline mutations In the NF2 geneby SSCP and heteroduplex analysis of cDNA and genomic DNA samplesfollowed by cloning and sequencing of mutant alleles. In thepresent report we describe 11 putative pathological mutations,including five nonsense mutations, three short insertions ordeletions cauing frameshifts and three missense mutations. Moststop mutations and frameshift mutations were found In Individualsexpressing a severe phenotype while one of the three missensemutations was associated with a mild phenotype. Four unrelatedNF2 patients of the 93 tested were found to have identical nonsensemutations caused by a C to T transition (C169) in a CpG dinucleotide,which is a potential mutational hotspot in the NF2 tumour suppressorgene.     

A definition and systems view of anaerobic capacity

The purpose of this paper is both to define terms used in exercise physiology, i.e. anaerobic capacity, anaerobic work capacity and anaerobic potential, and develop a systems perspective of anaerobic capacity. Philosophical argument is used to support the proposed definitions and systems view, which is an approach to assist in the universal acceptance of such terms amongst scientific investigators, coaches and athletes, and provide a focus on physiological mechanisms associated with anaerobic capacity which may be the subject of future investigation.     

Contribution of the distal tubule to potassium excretion in experimental glomerulonephritis

The renal adaptations that maintain potassium homeostasis in diffuse forms of glomerular disease are not well defined. Thus, handling of potassium by superficial nephron segments was examined in a rat model of antiglomerular basement membrane nephritis. Sampling the same nephron successively from the end and beginning of the distal tubule and the end of the proximal tubule allowed a segmental analysis. Despite a 40% reduction in GFR, potassium excretion in the glomerulonephritis animals was normal due to an increase in FEK. The proximal tubule and loop segment did not contribute to the enhanced FEK seen in these animals. In contrast, potassium entry along the distal tubule was significantly greater in the experimental group averaging 13.7 +/- 4.3 pmol/min compared to 1.2 +/- 1.7 pmol/min in controls (P less than 0.01). Multiple linear regression analysis showed that distal tubule potassium entry at any level of flow was enhanced in glomerulonephritis compared to controls (P less than 0.0001). Plasma aldosterone levels were similar in both groups of animals. Thus, the adaptation to potassium excretion seen in glomerulonephritis is partly achieved by the distal tubule through flow-rate independent mechanisms and appears to be independent of plasma aldosterone levels.     

The Role of Exercise in Cardiac Rehabilitation: A Nursing Perspective

A crucial component of cardiac rehabilitation programs is exercise therapy. The purpose of this paper is to describe the benefits of exercise and the role of nursing within these programs. Rehabilitation programs must be individualized by identifying different patient populations and appropriate nursing diagnoses. Thereby, benefits of the program are maximized in order to improve the individual's quality of life.     

A Comparison of Depressive Symptoms in Stroke and Primary Care: Applying Rasch Models to Evaluate the Center for Epidemiologic Studies-Depression Scale

OBJECTIVES: Clinical trials and community-based studies often include the Center for Epidemiologic Studies-Depression scale (CES-D) as a measure of depression outcome. We compared responses to symptom-related items on the CES-D by depressed stroke and primary-care patients for several purposes: 1) to illustrate the use of Item Response Theory (IRT)-based (Rasch) models for comparing scale functioning across different patient subgroups; and 2) to inform clinicians and outcome researchers about scale functioning and depressive symptomatology in stroke- compared with primary care-based depression. METHODS: Two data sources were analyzed, including 32 depressed patients who were 3 months poststroke, and 366 depressed primary-care patients. Presence of depression was based on a CES-D score 16 or higher. Rasch models were used to assess item fit and compare item hierarchies between depressed primary-care and stroke patients. RESULTS: Item hierarchies were similar for poststroke depression and primary care-based depression. Interpersonal disruption items were the most difficult to endorse for both groups. No items misfit the scale in primary-care depression. Items relating to restless sleep, unfriendliness, and crying slightly misfit the scale in stroke patients, that is, may measure a different trait. Differential item functioning (DIF) between the groups was identified for items relating to appetite, restless sleep, crying, and feeling disliked. CONCLUSIONS: Results generally supported the use of the CES-D as measure of depression outcome, particularly in primary care-based depression. DIF may imply that slightly different clusters of depressive symptoms are reported by depressed stroke patients compared with primary care, but this is conjectural given the small stroke sample size and the same items have been previously associated with bias in studies of large nonstroke samples. This study found Rasch models to be useful tools to investigate scale performance for different clinical applications.