Epitope affinity for MHC class I determines helper requirement for CTL priming.

We show here that priming and memory generation of antigen-specific CD8+ cytotoxic T lymphocytes (CTL) does not require help if the immunogen binds major histocompatibility complex (MHC) class I molecules with high affinity. This conclusion was based on the study of three chemically distinct optimal length CTL epitopes with high affinity for the restriction element Kb. In contrast, when two subdominant epitopes with intermediate MHC binding affinity were studied, either a class II MHC-restricted T helper cell epitope or administration of antibody to CD40 was required to obtain significant CTL priming. Depending on the epitope, one source of help was much more efficient than the other.

The effect on costs of the use of half-dose aprotinin for first-time reoperative coronary artery bypass patients.

Half-dose aprotinin previously has been shown to reduce bleeding and the need for blood transfusions, but the results of cost-reduction studies have been variable. The purpose of the present retrospective study was to compare, from the perspective of the acute care hospital as health care provider, the costs associated with first-time reoperative coronary artery bypass graft (CABG) surgery in patients who received half-dose aprotinin with the costs in those who did not. Medical records from 46 historical controls (first-time reoperative CABG patients receiving no aprotinin) and 51 half-dose aprotinin-treated patients were reviewed. A total of 36 variables were abstracted from the medical records for analysis. It was found that more aprotinin-treated patients did not require transfusion compared with nontreated patients (47% vs 26%). Twenty-one percent fewer aprotinin-treated patients received red blood cell transfusions, 21% fewer received plateletpheresis packs, and 19% fewer received fresh frozen plasma. Cost savings per patient receiving half-dose aprotinin compared with no aprotinin were approximately $878 in blood products and $1088 in total length of stay (including critical care), for total savings of $1966. When the cost of aprotinin ($450) was subtracted, the approximate net mean savings per patient were $1516. This did not include additional cost savings with aprotinin resulting from a median 19.5-minute shorter pump time. The authors conclude that the use of half-dose aprotinin results in reductions in surgical and associated hospitalization costs because of decreases in the length of hospital stay, including length of stay in critical care, and in the use of blood products.

Ocular pneumoplethysmography in head-injured patients.

Severe head injury is frequently associated with multiple trauma. In the comatose patient, endotracheal intubation and ventilator support are often required, if there is associated dyssynchronous spontaneous effort. The latter is managed with therapeutic (drug) paralysis. An elaborate life-support and monitoring system coupled with controlled paralysis limits the mobility of the patient for diagnostic procedures, and a continuing reevaluation of neurological status is difficult. Under these circumstances the ocular pneumoplethysmograph provides a simple rapid noninvasive assessment of ocular blood flow, and this reflects cerebral blood flow and alterations in brain compliance. Alterations in the therapeutic regimen can be based on these observations.

Preparing graphics for visual presentation.

In the beginning, the preparations and doing the graphics will take time, and the process will appear to be slow and tedious. Good graphics take time. However, the time will be lessened considerably when you have more hands-on experience. Graphics must be direct, simple, clear, and accurate. Preview and proof your graphics before production. For quick legibility preview, view your graphic at a distance of eight times the width of the graphic image. If you cannot read it, the audience will not be able to either. Be sure all lines are solidily inked and in proportion to the intended visual. Master one technique before expanding to others. Learn to visualize the end result of a rough draft. This will save you many redos and fewer changes later on. Finally, condition yourself to accept constructive critiques on your work, especially from graphics professionals and co-professionals. It may be an excellent way to improve the quality of your future presentations.