Comparison of five point-of-care prothrombin and activated partial thromboplastin time devices based on age of blood sample

Delays in processing statium (STAT) blood samples have led to the production of an increasing number of point-of-care tests. Product inserts recommend measuring blood samples immediately after procurement, suggesting that delays may invalidate the test results. We studied the effect of the age of blood samples on point-of-care (POC) prothrombin time (PT) and an activated partial thromboplastin time (aPTT) result. Informed consent was obtained from 11 patients undergoing cardiopulmonary bypass (CPB). Blood samples (40 mL) were taken from each patient. Each blood sample was used to perform five PT tests and six aPTT tests on five POC devices (Gem PCL, Hemochron 801, Hemochron Jr. Signature, Hemochron Response, Rapidpoint Coag) at three different sample ages [< 60 s (fresh blood), 10 and 18 min after sample collection]. Blood samples were procured in a plastic syringe devoid of air bubbles, which was left undisturbed between tests but was gently agitated before initiating the 10- and 18-min tests. For tests requiring citrated whole blood, a fraction of each sample was anticoagulated (3.8% citrate) at each age. Statistical analysis was used for comparison of test results for fresh blood to aged samples (10 and 18 min). Test values were recorded as International Normalized Ratio (INR) and seconds for PT and aPTT, respectively. Two devices, the Hemochron 801 and Hemochron response showed statistically, although not clinically, significant variation in PT test results when the samples were aged to 10 and 18 minutes. As for aPTT results, Hemochron 801, Hemochron response, Hemochron Jr. signature, and Gem PCL showed statistically significant variation at 18 minutes. One device (Hemochron 801) reported results with 10-min aged blood that were statistically different from fresh blood. None of the aPTT tests results from any device produced results with aged blood that were clinically different from fresh blood. This study suggests that, in the tests evaluated, blood samples that have aged 10 or 18 min will produce clinically relevant aPTT and PT results, respectively.     

Thoracic spinal intradural arachnoid cyst: report of two cases and review of literature

We report two cases of spinal intradural arachnoid cyst at the thoracic level, presenting with long-standing symptoms of spinal cord compression and MRI findings that were overlooked for sometime initially. Because of the rarity of this disease, and because of the subtle changes on MRI, there was a definite delay in the diagnosis. In this report we emphasize the value of MRI and CT myelography in this disorder, and the need for them to be strongly correlated with the progression of the clinical picture.     

Novel Phase I dose de-escalation design trial to determine the biological modulatory dose of the antiangiogenic agent SU5416.

PURPOSE: To determine the biological modulatory dose of SU5416, we employed a novel trial design, where "dose de-escalation" was based on demonstrable biological changes observed at the maximum tolerated dose. If such an effect was shown, dose de-escalation to a predefined dose level would occur to determine if the lower dose exhibited the same amount of pharmacodynamic effect as the higher dose. EXPERIMENTAL DESIGN: Ten patients with advanced solid tumors were enrolled at each dose level. One of the following pharmacodynamic effects was considered significant: (a) a 35% decrease in microvessel density in sequential tumor biopsies and (b) a 35% decrease in blood flow within tumor as assessed by dynamic contrast-enhanced magnetic resonance imaging. In addition, soluble E-selectin, soluble intercellular adhesion molecule, soluble vascular cell adhesion molecule, and plasma vascular endothelial growth factor were measured sequentially. RESULTS: Nineteen patients were enrolled. Sequential tumor biopsies in all evaluable patients showed an increase in microvessel density. Only one patient met the intended pharmacodynamic end point of >35% reduction in blood flow. There was a significant increase in both soluble E-selectin and soluble intercellular adhesion molecule levels pretreatment versus levels at the time of removal of patients from study (P = 0.04 and P = 0.0007, respectively). Levels of serum fibrinogen rose with therapy. There was a trend toward increase in plasma vascular endothelial growth factor levels. CONCLUSION: SU5416 does not result in decreased blood flow in tumors or a decrease in microvessel density. This corresponds to the lack of clinical activity seen with this agent. Our clinical trial design termed dose de-escalation is a novel approach to determine the in vivo biological effects of targeted therapies in cancer patients.     

Recurrent Legg-Calvé-Perthes disease revisited: fake or reality?

The objective of this study was to assess the course, the epidemiologic features and the prognosis of recurrent Legg-Calvé-Perthes disease. We reviewed seven reported cases and one personal case of recurrent Perthes' disease. In all cases, complete recovery from the previous episode was documented, and a thorough diagnostic work-up to rule out other diseases was undertaken. There were five boys. Age at onset ranged from 2 to 6 years. Five patients had bilateral involvement. Recurrence took place 1-5 years after complete healing of the initial one. Clinical and radiological pictures were similar to those found in primary Perthes' disease of the adolescent and consisted in a greater epiphyseal involvement. Recurrent Perthes' disease is very rare. We did not identify any risk factors for recurrence. A worse outcome is more closely related to an older age of the patient at recurrence than to recurrence itself.     

An autoregressive model-based method for contrast agent detection in ultrasound radiofrequency images

This paper presents a spectral autoregressive method dedicated to the detection of ultrasound contrast agents (USCA) from radiofrequency (rf) data. The method is based on second-order autoregressive (AR) modeling of the rf signal. Contrast agents induce a second harmonic, which may be efficiently detected through the AR spectrum using the magnitude of the second AR spectral peak (SM2). In contrast to multipulse methods that process two or more rf frames, our method processes a single rf frame. The method is tested by numerical simulation and on in vitro data for contrast agent concentrations ranging from 10(3) to 50 x 10(3) bubbles/ml (2 x 10(-6) to 10(-4) volumic concentration) and mechanical index (MI) ranging from 0.1 to 0.36. The results show that the proposed parameter SM2 enables one to detect correctly the contrast agent, in particular at low concentration and MI (the minimum difference in SM2 between tissue and USCA is 10 dB). Furthermore, the in-vitro data demonstrates that an adapted smoothing technique reduces the variability of SM2 and provides accurate and stable segmentation of the contrast agent perfusion region.     

Pain and terminal delirium research in the elderly

This article highlights new developments in assessment and management of pain and delirium.     

Long-term effects of acute and of chronic hypoxia on behavior and on hippocampal histology in the developing brain

Ten-day-old rat pups (P10) subjected to acute hypoxia (down to 4% O2) had as adults increased aggression (handling test), memory impairment (water maze test), and decreased CA1 cell counts. Pups subjected to chronic hypoxia (10% O2 from P0 to P21) had increased aggression, hyperactivity (open-field test), and decreased CA1 cell counts. Chronic hypoxia with superimposed acute hypoxia resulted in consequences that were not different from those of chronic hypoxia.