SPECIFIC HETEROLOGOUS ENHANCEMENT OF IMMUNE RESPONSES : VI. PARTIAL PURIFICATION OF A NONSPECIFIC ENHANCING FACTOR FROM SUPERNATES OF ALLOGENEICALLY STIMULATED HUMAN LYMPHOCYTE CELL LINES

The mixing of two histoincompatible human lymphocyte cell lines generated the release of a soluble factor which was capable of nonspecifically enhancing the in vitro immune response of normal mouse spleen cells against sheep erythrocytes. When active supernates were subjected to exclusion chromatography on Sephadex G-150 and BioGel P-150, the active principle eluted with molecules of approximately 35,000 mol wt. Column aliquots from similarly treated supernates from independent cultures of each lymphoid cell line were inactive. The human enhancing factor was concentrated and purified by ammonium sulfate fractionation, followed by Sephadex gel filtration and polyacrylamide gel electrophoresis.     

STUDIES ON ANTIBODY PRODUCTION : VIII. THE INHIBITORY EFFECT OF CHLORAMPHENICOL ON THE SYNTHESIS OF ANTIBODY IN TISSUE CULTURE

When lymph node fragments from previously immunized rabbits were stimulated in vitro to produce a secondary response, the continuous presence of 50 µg/ml (0.15 mM) of chloramphenicol in the medium during the entire incubation period of 15 to 21 days produced nearly complete suppression of the response. Concentrations as low as 5 µg/ml (0.015 mM) produced approximately 80 per cent suppression of the response. When 50 µg/ml of chloramphenicol was present during only the first 6 days of culture, the secondary response was reduced 90 per cent. When it was absent for the first 6 days but present for the next 9 to 15 days, the response was reduced only 40 per cent. Since over 95 per cent of the antibody of the secondary response in most experiments appeared in the medium after the 6th day, chloramphenicol apparently inhibits antibody production by interfering with some early phase of the response. It is suggested that this interference involves messenger RNA and that animal cells have appeared resistant to this drug only because their complement of messenger RNA present when the drug has been added is stable over the short periods during which protein synthesis has usually been studied.     

STUDIES ON ANTIBODY PRODUCTION : VI. THE COURSE, SENSITIVITY, AND HISTOLOGY OF THE SECONDARY RESPONSE IN VITRO

The in vitro anamnestic antibody response of popliteal lymph node fragments to additions of antigen closely resembles the in vivo anamnestic antibody response in its sensitivity to antigen, in the time course of antibody production, and in the sequence of appearance and the morphology of the antibody containing cells. Most of the cells responsible for antibody synthesis remain in the explant and do not migrate, although a few can be found in the outgrowing sheet of cells. The smallest concentration of bovine serum albumin which stimulates an anamnestic response in vitro is about 1 x 10^–9 gm/ml.     

STUDIES ON ANTIBODY PRODUCTION : XIII. THE EFFECT OF CHLORAMPHENICOL ON PRIMING IN MICE

Young adult mice were primed with 20 Lf (56 µg) of diphtheria toxoid and given a second injection of the same size 40 days later. This procedure produces a reproducible secondary response which can be used as a standard. Chloramphenicol in maximum dosage prevents the unknown process by which the animal is primed for the second response. To be fully inhibitory, the drug must be given from the hour of the first antigen injection in maximum dosage for 2 weeks. A delay of 48 hours in starting the drug allows completion of the priming process, and shorter delays produce partial inhibition. Hence the initiation of priming is a rapid process sensitive to chloramphenicol. Subsequent changes in the cell population necessary for the full development of priming are not sensitive to chloramphenicol. The secondary antibody response is not inhibited in mice by chloramphenicol at the doses employed.     

Lung cancer detection in patients with airflow obstruction identified in a primary care outpatient practice

INTRODUCTION: This prospective study describes a community-based lung cancer identification project focusing on high-risk patients who receive general care in a primary care outpatient practice. Within 1 calendar year, a simple questionnaire was completed in 1,296 patients > 50 years old to identify 430 patients at high risk of lung cancer (smoking, family history of aerodigestive tract cancer, or occupational exposures). Spirometric abnormalities were found in 126 of these patients. METHODS: Chest posteroanterior radiographs, thoracic CT scans, and sputum cytology were offered to subjects with airflow obstruction (n = 126). Eighty-eight patients underwent all tests. Thirty-eight patients refused or could not consent in a timely fashion. RESULTS: Six cancers were found in the screened group, and all were treated. Two more cancers were found in the nonscreened patients with airflow obstruction. Both were treated by surgical resection or radiation therapy. Costs per cancer found were $11,925 per patient. CONCLUSIONS: Case finding in high-risk patients in a primary care population can be accomplished at a relatively low cost.     

Clinical outcomes with unfractionated heparin monitored by anti-factor Xa vs. activated partial Thromboplastin time

Anti-factor Xa (anti-Xa) monitoring of unfractionated heparin (UFH) is associated with less time to achieve therapeutic anticoagulation compared to the activated partial thromboplastin time (aPTT). However, it is unknown whether clinical outcomes differ between these methods of monitoring. The aim of this research was to compare the rate of venous thrombosis and bleeding events in patients that received UFH monitored by anti-Xa compared to the aPTT. A retrospective review of electronic health records identified adult patients that received UFH given intravenously (IV) for ≥2 days, with either anti-Xa or aPTT monitoring at an academic tertiary care hospital. This was a pre/post study design conducted between January 1 to December 30, 2014 (aPTT), and January 1 to December 30, 2016 (anti-Xa). All UFH adjustments were based on institutional nomograms. The primary outcome was venous thrombosis and the secondary outcome was bleeding, both of which occurred between UFH administration and discharge from the index hospitalization. A total of 2500 patients were in the anti-Xa group and 2847 patients aPTT group. Venous thrombosis occurred in 10.2% vs 10.8% of patients in the anti-Xa and aPTT groups, respectively (P = .49). Bleeding occurred in 33.7% vs 33.6% of patients in the anti-Xa and aPTT groups, respectively (P = .94). Anti-Xa monitoring was not an independent predictor of either outcome in multivariate logistic regression analyses. Our study found no difference in clinical outcomes between anti-Xa and aPTT-based monitoring of UFH IV.     

Characterization of invasive Neisseria meningitidis from Atlantic Canada, 2009 to 2013: With special reference to the nonpolysaccharide vaccine targets (PorA,factor H binding protein,Neisseria heparin-binding antigen and Neisseria adhesin A)

BACKGROUND:Serogroup B Neisseria meningitidis (MenB) has always been a major cause of invasive meningococcal disease (IMD) in Canada. With the successful implementation of a meningitis C conjugate vaccine, the majority of IMD in Canada is now caused by MenB.OBJECTIVE:To investigate IMD case isolates in Atlantic Canada from 2009 to 2013. Data were analyzed to determine the potential coverage of the newly licensed MenB vaccine.METHODS:Serogroup, serotype and serosubtype antigens were determined from IMD case isolates. Clonal analysis was performed using multilocus sequence typing. The protein-based vaccine antigen genes were sequenced and the predicted peptides were investigated.RESULTS:The majority of the IMD isolates were MenB (82.5%, 33 of 40) and, in particular, sequence type (ST)-154 B:4:P1.4 was responsible for 47.5% (19 of 40) of all IMD case isolates in Atlantic Canada. Isolates of this clone expressed the PorA antigen P1.4 and possessed the nhba genes encoding for Neisseria heparin-binding antigen peptide 2, which together matched exactly with two of the four components of the new four-component meningococcal B vaccine. Nineteen MenB isolates had two antigenic matches, another five MenB and one meningitis Y isolate had one antigenic match. This provided 75.8% (25 of 33) potential coverage for MenB, or a 62.5% (25 of 40) overall potential coverage for IMD.CONCLUSION:From 2009 to 2013, IMD in Atlantic Canada was mainly caused by MenB and, in particular, the B:4:P1.4 ST-154 clone, which accounted for 47.5% of all IMD case isolates. The new four-component meningococcal B vaccine appeared to offer adequate coverage against MenB in Atlantic Canada.