Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography

The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.     

Dipeptidyl peptidase IV is down-regulated in rat hepatoma cells at the mRNA level

Dipeptidyl peptidase IV (DPP-IV) is a cell surface ectopeptidase that has been implicated in cell-extracellular matrix interactions, lymphocyte growth and the regulation of biological peptides. Previous studies have shown that immunostaining for DPP-IV and DPP-IV enzyme levels is decreased in hepatoma cells and levels have been correlated with the ability of such cells to adhere in vitro. The aim of this paper was to measure DPP-IV enzyme levels in rat hepatoma cells and to examine whether changes were associated with alterations at the mRNA level. The results indicate a greater than 90% reduction in DPP-IV enzyme levels in two rat hepatoma cell lines, HTC and H35, compared with rat hepatocytes. Enzyme levels of the control enzyme leucine aminopeptidase (LAP) were not decreased. mRNA studies indicated that these changes were associated with similar reductions in rat DPP-IV mRNA. It is concluded that DPP-IV is markedly reduced at the protein, enzyme and mRNA levels in rat hepatoma cells. The significance of these changes is unclear but may lead to decreased extracellular matrix interactions by such cells.     

FM sonography in diffuse liver disease: prospective assessment and blinded analysis

FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease.     

Epidemiology of migraine headache in Santiago, Chile: a prevalence study

Objective . To describe the importance of migraine in Santiago, Chile, by analyzing its prevalence, clinical features and impact by age, gender and socioeconomic status. Methods . In 1993, a representative sample of 1,540 adults of the province of Santiago were interviewed using a standard questionnaire. A total of 1,385 (89.9%) subjects responded to the survey. Initially, a designated member of each household responded to the questionnaire. Subsequently, each household member with headaches was asked to respond to questions about severity, frequency, location, duration, associated symptoms and impact in work and social activities of their most frequent headaches. Migraine diagnoses were determined in accordance with the International Headache Society (IHS) criteria of 1988. Results. Recurrent headaches in the past year were found in 516 (36.82%) respondents, 145 (28.1%) males and 371 (71.9%) females. Total prevalence of migraine was found to be 7.3% (95%, CI 5.9–8.6); 11.9% (95% CI 9.6–14.2) in females and 2.0% (95% CI 0.9–3.0) in males. Overall, migraine constituted 19.6% (101/516) of all headaches reported in this sample. The prevalence did not vary significantly by age groups or socioeconomic status (SES). Migraine with aura had an overall prevalence of 3.5% (CI 0.8–7.1), and was significantly more frequent in females. In 60–70% of cases the attacks lasted 2–6 h and the frequency was 3.3 and 3.4 per month in females and males respectively. Both males and females reported significantly high percentages of attacks during work. Conclusions . Migraine prevalence in a sample of adults of Santiago is similar to that reported in previous studies using IHS criteria. Women of all socioeconomic levels are at an increased risk.     

Production and characterization of a new monoclonal antibody effective in recognizing the CD3 T-cell associated antigen in formalin-fixed embedded tissue

Phenotypic analysis of lymphoproliferative disorders is now considered mandatory for accurate classification which is the basis for optimum patient management. This is presently carried out in most cases using a range of antibodies recognizing B and T-cell antigens effective in paraffin sections, and an antibody to CD3 is currently a key member of such panels, indicating T-cell phenotype. Current antibodies to CD3 are polyclonal with the inherent disadvantages of this type of reagent compared to monoclonal antibodies. In this study, we have used a recombinant fusion protein representing part of the epsilon subunit of the CD3 molecule to generate a novel monoclonal antibody (NCL-CD3-PS1) effective in paraffin sections. The antibody has been characterized biochemically and by immunohistochemistry using a wide range of normal and pathological tissues. Lineage and phenotype specificity have been supported in our study and results from other laboratories are awaited with interest.