Clonal diversity of Ig and T-cell receptor gene rearrangements in childhood B-precursor acute lymphoblastic leukaemia

The majority of paediatric B precursor acute lymphoblastic leukaemias in children are derived from a single transformed haematopoietic cell with complete or partial VDJ recombination within the immunoglobulin heavy chain gene. A high frequency of patients also show rearrangements within TCRdelta and TCRgamma loci and in up to 40% of children there is an excess of immune system gene rearrangements compared with the number of identified alleles of immune system genes, suggesting the presence of multiple leukaemic subclones -clonal diversity. It has been observed by us and other investigators that in individual patients the pattern of immune system gene rearrangements often changes between presentation and relapse. In order to explore the possibility that clonal diversity plays a biological role during disease progression we optimised methods for subclone detection and analysed the prognostic significance of clonal diversity among 75 children with B precursor-ALL. Our results suggest that clonal diversity plays a role in disease progression as patients with oligoclonal disease showed a significantly shorter disease free survival than patients with monoclonal disease. This trend was of particular importance in the 'standard risk' group of ALL where aggressive disease could not be recognised by other means. In addition, generation of independent subclones from an early, non-rearranged tumour progenitor appears to be a common feature among leukaemias with aggressive clinical behaviour. We speculate on the type of genetic factors which may participate both in the generation of subclones and also in wider genomic instability and which are likely to be required for the aggressive clinical phenotype in children with ALL.     

Incidence, predictors, and outcome of thrombosis after successful implantation of drug-eluting stents

Context  Traditionally, stent thrombosis has been regarded as a complication of percutaneous coronary interventions during the first 30 postprocedural days. However, delayed endothelialization associated with the implantation of drug-eluting stents may extend the risk of thrombosis beyond 30 days. Data are limited regarding the risks and the impact of this phenomenon outside clinical trials. Objective  To evaluate the incidence, predictors, and clinical outcome of stent thrombosis after implantation of sirolimus-eluting and paclitaxel-eluting stents in routine clinical practice. Design, Setting, and Patients  Prospective observational cohort study conducted at 1 academic hospital and 2 community hospitals in Germany and Italy. A total of 2229 consecutive patients underwent successful implantation of sirolimus-eluting (1062 patients, 1996 lesions, 2272 stents) or paclitaxel-eluting (1167 patients, 1801 lesions, 2223 stents) stents between April 2002 and January 2004. Interventions  Implantation of a drug-eluting stent (sirolimus or paclitaxel). All patients were pretreated with ticlopidine or clopidogrel and aspirin. Aspirin was continued indefinitely and clopidogrel or ticlopidine for at least 3 months after sirolimus-eluting and for at least 6 months after paclitaxel-eluting stent implantation. Main Outcome Measures  Subacute thrombosis (from procedure end through 30 days), late thrombosis (>30 days), and cumulative stent thrombosis. Results  At 9-month follow-up, 29 patients (1.3%) had stent thrombosis (9 [0.8%] with sirolimus and 20 [1.7%] with paclitaxel; P = .09). Fourteen patients had subacute thrombosis (0.6%) and 15 patients had late thrombosis (0.7%). Among these 29 patients, 13 died (case fatality rate, 45%). Independent predictors of stent thrombosis were premature antiplatelet therapy discontinuation (hazard ratio [HR],  89.78; 95% CI, 29.90-269.60; P<.001), renal failure (HR,  6.49; 95% CI, 2.60-16.15; P<.001), bifurcation lesions (HR,  6.42; 95% CI, 2.93-14.07; P<.001), diabetes (HR,  3.71; 95% CI, 1.74-7.89; P = .001), and a lower ejection fraction (HR,  1.09; 95% CI, 1.05-1.36; P<.001 for each 10% decrease). Conclusions  The cumulative incidence of stent thrombosis 9 months after successful drug-eluting stent implantation in consecutive "real-world" patients was substantially higher than the rate reported in clinical trials. Premature antiplatelet therapy discontinuation, renal failure, bifurcation lesions, diabetes, and low ejection fraction were identified as predictors of thrombotic events.      

A simplified nutrition screen for hospitalized patients using readily available laboratory and patient information

OBJECTIVE: We assessed admission screening information that best identifies patients who are at risk for malnutrition-related complications (MRCs). METHODS: We evaluated 13 patient characteristics associated with MRC for adults screened over a 3-mo period (n = 448) to determine which factors correlated best with the risk level assigned. The existing screen stratified patients into four levels defined as no risk, mild risk, moderate, and high risk for MRC. The analyzed variables were weight for height, wound, surgery/cancer therapy, fever, vomiting/diarrhea, poor oral intake, no oral intake, unplanned weight loss, malnutrition-related admission diagnosis, serum albumin, white blood cell count, hemoglobin, and total lymphocyte count. We modeled the relation between assigned MRC and the predictors by using state-of-the-art methods. RESULTS: The characteristics that correlated best with MRC risk level assignment were occurrence of a wound, poor oral intake, malnutrition-related admission diagnosis, serum albumin value, hemoglobin value, and total lymphocyte count. A model using four variables (malnutrition-related admission diagnosis, serum albumin value, hemoglobin value, and total lymphocyte count) was almost as good as that using six predictors. CONCLUSIONS: The ability of admission information to accurately reflect MRC risk is crucial to early initiation of restorative medical nutritional therapy. There is currently no uniform or proved standard for identifying MRC risk within 24 h of acute care admission. The ideal nutritional screen correlates well with the occurrence of MRC and also uses data routinely obtained at admission. The models described can be uniformly used by hospitals to screen patients for MRC risk.     

The experimental toxicology of metallic mercury on the murine peripheral motor system: a novel method of assessing axon calibre spectra using the phrenic nerve

The toxicology of metallic mercury on motor neurons and their processes requires further work to resolve controversial implications in the aetiology of human motor neuron disease (MND). The assessment of experimental neurotoxicity in the peripheral motor system is, however, technically problematic and difficult to interpret. The mean number of axons in a nerve can vary considerably due to a high degree of biological variation. Atrophy of large axons can appear as loss when, in fact, their numbers appear in smaller diameter axonal categories. We addressed these quantitative problems using the murine phrenic nerve (MPN), a mono-fascicular, predominantly motor nerve as a model system. One micrometer transverse sections of gluteraldehyde/osmium tetroxide fixed MPNs were stained for myelin using a silver technique. Axon areas were measured from digital images of the nerve in cross-section (ImagePro Plus software) and transformed to circular diameter equivalents, then displayed as frequency distributions. We found a high biological variation in the mean axon number between paired nerves within experimental groups. Therefore, axon diameter data within individuals group was pooled. Theoretical simulation of axonal degeneration, atrophy and hypertrophy of larger myelinated axons (also affected in MND) were modelled by manipulating the original data set. With this model, by comparing normal distributions, it is possible to distinguish axonal atrophy, degenerative loss, and hypertrophy as distinct pathological processes in the large calibre axon subgroup that are selectively vulnerable to metallic toxins such as mercury.     

Secondary radial head dislocation and dysplasia of the lateral condyle after elbow trauma in children

We report five cases of a rare complication of childhood fractures of the elbow region. The complication consists of posttraumatic dissolution of the lateral humeral condyle followed by secondary radial head overgrowth and dislocation. The initial injuries ranged from displaced lateral condyle fractures (three patients) to a supracondylar fracture and an open elbow dislocation. Dysplasia of the lateral humeral condyle was first noted 1 to 4 years after the trauma (mean, 2.5 years) and seemed to be caused by removal of the displaced fracture fragment in one patient, and possibly by malfixation and repeated surgical procedures in the others. Because of loss of motion, ulnar nerve irritation, and cosmetic deformities, corrective osteotomies had to be performed in four patients and additional radial head removal in two patients.     

Simultaneous HPLC determination of nitrendipine and impurities of the process of synthesis

A method has been developed for separation of nitrendipine and its impurities of reaction partners and side reaction products by high-performance liquid chromatographic method on a RP-18 column and detection at 238 nm. The mobile phase composition that provided an acceptable nitrendipine resolution, in large excess and possible impurities, in a short elution time, is methanol:water (70:30) and pH 3. Linearity (r≥0.999), reproducibility (RSD=0.8–1.4%), determination limit (0.5–2%) and recovery (99.8–102.3) were validated and found to be satisfactory. This method enables monitoring of the process of synthesis, as well as the choice of the synthetic design.     

Non-invasive optical monitoring of the newborn piglet brain using continuous-wave and frequency-domain spectroscopy.

We have used continuous-wave (CW) and frequency-domain spectroscopy to investigate the optical properties of the newborn piglet brain in vivo and non-invasively. Three anaesthetized, intubated, ventilated and instrumented newborn piglets were placed into a stereotaxic instrument for optimal experimental stability, reproducible probe-to-scalp optical contact and 3D adjustment of the optical probe. By measuring the absolute values of the brain absorption and reduced scattering coefficients at two wavelengths (758 and 830 nm), frequency-domain spectroscopy provided absolute readings (in contrast to the relative readings of CW spectroscopy) of cerebral haemoglobin concentration and saturation during experimentally induced perturbations in cerebral haemodynamics and oxygenation. Such perturbations included a modulation of the inspired oxygen concentration, transient brain asphyxia, carotid artery occlusion and terminal brain asphyxia. The baseline cerebral haemoglobin saturation and concentration, measured with frequency-domain spectroscopy, were about 60% and 42 microM respectively. The cerebral saturation values ranged from a minimum of 17% (during transient brain asphyxia) to a maximum of 80% (during recovery from transient brain asphyxia). To analyse the CW optical data, we have (a) derived a mathematical relationship between the cerebral optical properties and the differential pathlength factor and (b) introduced a method based on the spatial dependence of the detected intensity (dc slope method). The analysis of the cerebral optical signals associated with the arterial pulse and with respiration demonstrates that motion artefacts can significantly affect the intensity recorded from a single optode pair. Motion artefacts can be strongly reduced by combining data from multiple optodes to provide relative readings in the dc slope method. We also report significant biphasic changes (initial decrease and successive increase) in the reduced scattering coefficient measured in the brain after the piglet had been sacrificed.     

The role of in vitro diagnostic companies in reducing laboratory error.

Laboratory errors have a significant impact on patient safety. The manufacturers of in vitro diagnostic (IVD) products play an important role in the reduction of laboratory errors by ensuring the highest possible safety and efficacy of their products. In order to achieve this, the IVD industry has implemented rigorous product development and manufacturing processes. Many IVD companies apply Six Sigma principles in order to minimize variability within the whole product life cycle, starting with customer requirements, through product design and manufacture, as well as management of the potential issues that occur after the products have been released for use. A closer look into this process is presented here, using an evacuated blood collection tube as a model device.