Electronmicroscopic examination of white cell reduction by four white cell-reduction filters

The mechanisms of white cell (WBC) reduction in 16-hour-old CPDA-1 red cell (RBC) concentrates by filtration on a column filter and on three different flatbed filters were studied by electron microscopy, with special emphasis on cell-to-cell interaction, cell damage, and interaction of blood cells with the material. Generally, lymphocytes were removed by mechanical sieving and monocytes by adherence and mechanical sieving. Granulocyte depletion occurred by mechanical sieving, direct adhesion to the fibers, and indirect adhesion to activated and spread platelets. In the column filter, most granulocytes were captured by adhesion. In the coarse layers of two of the flatbed filters, indirect adhesion was most prominent, whereas direct adhesion was most prominent in the other flatbed filter. For the most part, granulocytes were captured by direct adhesion in the fine layers, but in one flatbed filter, capture apparently occurred by mechanical sieving. The results of this study suggest that the efficiency and the mechanism of WBC reduction depend on the physicochemical characteristics of the non-woven materials in the filters as well as the cellular composition of the RBC concentrates.     

Variation and importance of aspirin resistance in patients with known cardiovascular disease

AIM: To investigate whether aspirin resistance is a persistent condition, and to evaluate if aspirin resistance affects one-year clinical outcome. METHODS AND RESULTS: Previously we studied 298 patients admitted to hospital with symptoms suggestive of an acute myocardial infarction (MI) despite treatment with aspirin, and 70 patients (23.5%) were aspirin resistant. In the present study, platelet function was reassessed by use of a Platelet Function Analyzer-100 one year later. A total of 187 patients were re-examined, and 17 (9.1%) demonstrated aspirin resistance. Of these 17 patients, 12 also exhibited aspirin resistance at baseline resulting in a 6% (12/187) prevalence of persistent aspirin resistance. A total of 34 patients had changed from aspirin resistant at baseline to aspirin sensitive at follow-up. We found a significant decrease in the prevalence of aspirin resistance from baseline (43%) to follow-up (11%) in patients with MI at baseline (p=0.0018). Furthermore, a significant decrease was found for patients without MI at baseline (20% to 9%, p=0.0009). During follow-up, 17% (12/70) of the patients with aspirin resistance at baseline suffered death, MI or stroke compared to 16% (37/227) of aspirin sensitive patients (p=0.868). CONCLUSION: The prevalence of aspirin resistance varies with the clinical status of the patients, and indeed an acute MI is associated with temporary aspirin resistance. We also found that 6% of patients demonstrate persistent aspirin resistance. The presence of aspirin resistance did not affect one-year clinical outcome.     

Accuracy of the clinical evaluation for frontotemporal dementia

BACKGROUND: Without a definitive clinical test, the early diagnosis of frontotemporal dementia (FTD) can be difficult. OBJECTIVE: To evaluate the accuracy of the clinical evaluation for FTD. DESIGN: Retrospective assessment of consensus criteria for FTD, neuropsychological measures, magnetic resonance images, and single-photon emission computed tomography/positron emission tomography (SPECT/PET) scans at baseline compared with a standard of subsequent clinical diagnosis after follow-up and reevaluation to year 2. SETTING: University hospital. PATIENTS: A total of 134 patients referred for clinical evaluation of suspected FTD. These patients had 1 or more core or supportive features of FTD in the absence of another etiology on initial assessment. MAIN OUTCOME MEASURES: Sensitivities, specificities, and predictive values of consensus criteria for FTD, magnetic resonance images, and SPECT/PET scans at initial assessment. RESULTS: The sensitivities and specificities for the diagnosis of FTD were 36.5% and 100.0% for consensus criteria, 63.5% and 70.4% for magnetic resonance images, and 90.5% and 74.6% for SPECT/PET scans, respectively. With a previous prevalence of nearly 50% for FTD, the positive predictive value was greatest for consensus criteria (100.0%), and the negative predictive value was greatest for SPECT/PET (89.8%). The initial neuropsychological results did not distinguish FTD, but the pattern of progression (worse naming and executive functions and preserved constructional ability) helped establish the diagnosis at year 2. CONCLUSIONS: Consensus criteria for FTD and neuropsychological measures lacked sensitivity for FTD; however, neuroimaging, particularly functional brain studies, greatly increased the sensitivity of detecting FTD. The clinical diagnosis of FTD needs to combine neuropsychiatric features with SPECT or PET findings while following the changes on neuropsychological tests.     

Role of diffusion MRI in diagnosis of spinal cord infarction in children

Anterior spinal artery (ASA) infarction is a rare but well-described cause of flaccid paraparesis in adults, presenting with a high thoracic spinothalamic sensory level and preservation of dorsal column function. Careful sensory examination, demonstrating loss of spinothalamic modalities with preservation of dorsal column modalities, supports a clinical diagnosis of ASA infarction. Findings on conventional MRI of the spinal cord are often non-specific, and diffusion-weighted imaging (DWI) is not routinely performed. We describe four children with ASA infarction after minor trauma. DWI was performed in all cases and confirmed the clinical diagnosis.     

Health Effects of Exposure to High Concentrations of Automotive Emissions

On-site and remote health evaluations were performed on 550 employees of the Triborough Bridge and Tunnel Authority in New York City. Extremely high ambient air pollution was observed. Carbon monoxide averaged 63 ppm over a 30-day period with a maximum hourly concentration of 217 ppm in one facility. Eighty-five percent of the smoking and 47% of the nonsmoking tunnel workers had carboxyhemoglobin saturations in excess of 3%. A high percentage of the group had symptoms suggestive of chronic bronchitis; airway resistance was elevated in one third and almost all bridge and tunnel workers had an increase in closing volume, suggesting small airway disease.