A psychometric analysis of the Quality of Life-Cancer Survivors (QOL-CS) in survivors of childhood cancer

Given the increasing interest in quality of life research in cancer survivorship, psychometric properties of the Quality of Life-Cancer Survivors (QOL-CS) were explored in a group of childhood cancer survivors. The QOL-CS is a 41-item visual analog scale composed of four multi-item sub-scales (physical well-being, psychological well-being, social well-being, spiritual well-being) and two sub-components (fears, distress). This instrument was incorporated in a mailed survey completed by 177 respondents. The underlying factor structure and internal reliability of the instrument were explored. A preliminary assessment of the external validity of the factor structure was undertaken. Results of a factor analysis were theoretically consistent with elements assessed in the QOL-CS, although misclassification of several items was noted and discussed. Internal-consistency reliability was very good (Cronbach's α = 0.80–0.89) for five of the six factors. Moderate (0.30 < r < 0.45) to high (r > 0.60) concurrent validity was observed for four factors. Discriminant validity was noted across groups defined by health and social status variables. Psychometric analysis indicated that the instrument measured distinct and relevant domains of quality of life for childhood cancer survivors, but in its current form does not appear to be an optimal measure of quality of life in this population. This revised version was published online in June 2006 with corrections to the Cover Date.     

Dynamic magnetic resonance imaging of human brain activity during primary sensory stimulation.

Neuronal activity causes local changes in cerebral blood flow, blood volume, and blood oxygenation. Magnetic resonance imaging (MRI) techniques sensitive to changes in cerebral blood flow and blood oxygenation were developed by high-speed echo planar imaging. These techniques were used to obtain completely noninvasive tomographic maps of human brain activity, by using visual and motor stimulus paradigms. Changes in blood oxygenation were detected by using a gradient echo (GE) imaging sequence sensitive to the paramagnetic state of deoxygenated hemoglobin. Blood flow changes were evaluated by a spin-echo inversion recovery (IR), tissue relaxation parameter T1-sensitive pulse sequence. A series of images were acquired continuously with the same imaging pulse sequence (either GE or IR) during task activation. Cine display of subtraction images (activated minus baseline) directly demonstrates activity-induced changes in brain MR signal observed at a temporal resolution of seconds. During 8-Hz patterned-flash photic stimulation, a significant increase in signal intensity (paired t test; P less than 0.001) of 1.8% +/- 0.8% (GE) and 1.8% +/- 0.9% (IR) was observed in the primary visual cortex (V1) of seven normal volunteers. The mean rise-time constant of the signal change was 4.4 +/- 2.2 s for the GE images and 8.9 +/- 2.8 s for the IR images. The stimulation frequency dependence of visual activation agrees with previous positron emission tomography observations, with the largest MR signal response occurring at 8 Hz. Similar signal changes were observed within the human primary motor cortex (M1) during a hand squeezing task and in animal models of increased blood flow by hypercapnia. By using intrinsic blood-tissue contrast, functional MRI opens a spatial-temporal window onto individual brain physiology.     

Time course of intermittent hypoxia-induced impairments in resistance artery structure and function

We previously demonstrated that chronic exposure to intermittent hypoxia (CIH) impairs endothelium-dependent vasodilation in rats. To determine the time course of this response, rats were exposed to CIH for 3, 14, 28, or 56 days. Then, we measured acetylcholine- and nitroprusside-induced vasodilation in isolated gracilis arteries. Also, we measured endothelial and inducible nitric oxide synthase, nitrotyrosine, and collagen in the arterial wall and urinary isoprostanes. Endothelium-dependent vasodilation was impaired after 2 weeks of CIH. Three days of CIH was not sufficient to produce this impairment and longer exposures (i.e. 4 and 8 weeks) did not exacerbate it. Impaired vasodilation was accompanied by increased collagen deposition. CIH elevated urinary isoprostane excretion, whereas there was no consistent effect on either isoform of nitric oxide synthase or nitrotyrosine. Exposure to CIH produces functional and structural deficits in skeletal muscle resistance arteries. These impairments develop within 2 weeks after initiation of exposure and they are accompanied by systemic evidence of oxidant stress.     

Automated sequencing detects all mutations in Northern Irish patients with phenylketonuria and mild hyperphenylalaninaemia

In the first phase of the Northern Ireland PKU Study, we used automated sequencing to identify the spectrum of mutations in a random group of 32 unrelated phenylketonuria (PKU) families. We also investigated 7 Northern Irish patients with mild hyperphenylalaninaemia not requiring dietary intervention (MHP, previously referred to as non-PKU HPA). Disease-causing mutations were identified on all 78 investigated chromosomes. We found 23 different mutations, including 20 missense, 1 nonsense and 2 splice site mutations. All mutations were located within exons or at intronexon boundaries of the phenylalanine hydroxylase gene. Seven mutations occurred at CpG sites, confirming these sites as mutation hot-spots in PKU. Mutations R408W and I65T are the two commonest PKU mutations in the Northern Irish population. Two mutations (T380M and V245A) can be characterized as MHP mutations; they are quasi dominant markers for MHP since they cause mild hyperphenylalaninaemia even when occurring in conjunction with the most severe PKU mutations. The results have proven valuable for the development of a routine PKU mutation analysis system in Northern Ireland.     

Genotype-dependence of gabapentin and pregabalin sensitivity: the pharmacogenetic mediation of analgesia is specific to the type of pain being inhibited

The antiepileptic drug, gabapentin, and another structurally related compound, pregabalin, are increasingly employed in the pharmacotherapy of chronic pain states, although their primary mechanism of action remains a topic of active study. A genomic approach to the study of these drugs may elucidate their potentially novel mechanisms. We examined the heritability of sensitivity to analgesia from gabapentin and pregabalin as a precursor to linkage mapping efforts. Accordingly, 11 inbred mouse strains were tested for inhibition of nociception by gabapentin or pregabalin (50-300 mg/kg, i.p.) in two different preclinical assays of inflammatory pain, the formalin test (5% formalin; 20 microl) and zymosan thermal hyperalgesia on the paw-withdrawal test (3 mg/ml zymosan; 20 microl). Significant strain-dependence of drug action was noted in each case, indicating that sensitivity to these analgesics is heritable. Furthermore, the pattern of strain sensitivities to gabapentin and pregabalin were mostly similar, supporting the notion that they act via similar genetic and physiological mechanisms. However, there was virtually no correlation between strain sensitivities to pregabalin inhibition of formalin nociception and zymosan thermal hyperalgesia. In light of previous data from our laboratory and others regarding morphine analgesia, we now establish and empirically demonstrate the general principle that pharmacogenetic mechanisms underlying analgesic sensitivity are specific to the type of pain being inhibited. This has considerable implications for ongoing pharmacogenetic investigations and, more generally, for the choices of preclinical models of pain used in drug development.     

Automated determination of urinary creatinine without sample dilution: theory and practice

The rate of the Jaffé reaction depends on the concentration of sodium hydroxide; the pseudo-first-order rate constant of the reaction, at 37 degrees C in 10 mmol/L picrate solution, is 0.004 mmol/L. We formulated an automated method to determine urinary creatinine directly without manual sample dilution. The conditions are as follows: 10 mmol/L picrate and 60 mmol/L sodium hydroxide (final concentrations); ratio of sample to final volume, 1:41; temperature, 37 degrees C; wavelengths of measurement, 500 or 510 nm; interval of measurement, 30 to 90 s; and mode of measurement, kinetic. Determinations of creatinine in patients' samples by the new method compared favorably with those obtained with the AutoAnalyzer and aca. The run-to-run CVs were 3.6% or less, and the method was accurate for concentrations of creatinine up to 3000 mg/L. We recommend this method as a good replacement for the AutoAnalyzer or aca methods.     

The assessment of the arterial supply to the lungs in pseudotruncus arteriosus and truncus arteriosus type IV in relation to surgical repair

The arterial supply to the lungs was assessed in a group of 44 patients with pseudotruncus arteriosus and truncus arteriosus Type IV with a view to surgical correction using a homograft conduit and closure of the ventricular-septal defect. Biplane right ventricular angiography was performed in all patients and selective catheterization of the collateral vessels was performed in 24 patients above the age of five years. In those patients where a blind right ventricular infundibulum was identified (pseudotruncus arteriosus, pulmonary atresia, and ventricular-septal defect) there were 38 patients in whom elements of the pulmonary arteries were identified in 95 per cent, and 76 per cent of the patients had anatomy suitable for complete surgical repair. In the group where a right ventricular infundibulum was absent (truncus arteriosus Type IV, absent sixth arch, and solitary aortic trunk with absent pulmonary arteries) there were four patients in whom the sole blood supply to the lungs was derived from aortic collateral vessels and all of the cases were inoperable. The collateral circulation to the lungs is described in both groups and the value of selective catheterization of these vessels is stressed. The diagnostic value of angiographic identification of the right ventricular infundibulum is emphasized as a pointer to potentially operable cases among a group of patients who have similar clinical features.     

Simultaneous measurement of aortic and left ventricular pressures in aortic stenosis using a double lumen pigtail catheter

This technical note describes a double lumen pigtail catheter that can facilitate measurement of the aortic valve gradient in patients with aortic stenosis. The catheter is passed retrograde into the left ventricle with the aid of a flexible guide wire. In two patients the measured gradient was not significantly different from that obtained using two systemic arterial catheters.