Molecular analysis of the interaction of p56lck with the CD4 and CD8 antigens.

The CD4 and CD8 antigens on the surface of T cells appear to bind to major histocompatibility complex (MHC) class II and I antigens, respectively. These antigens also synergize with the Ti(TcR)/CD3 complex in the potentiation of T-cell proliferation. Our earlier work demonstrated that the CD4 and CD8 receptors are coupled to a protein-tyrosine kinase termed p56lck from normal and transformed T lymphocytes. The p56lck protein is a member of the src family and its homology with receptor-kinases such as the epidermal growth factor receptor (EGFR) make it an important candidate in signal transduction. In this paper, we show in transfectants that p56lck interacts with the cytoplasmic tail of the CD4 antigen. Murine p56lck can interact across species with the human CD4 receptor. Furthermore, peptide competition studies showed that a specific sequence within the cytoplasmic tail of CD4 interacts with the kinase. Cysteine residues also appear to play key roles in this interaction. Lastly, we show biochemically that the CD4:p56lck complex can physically associate with the epsilon chain of the CD3 complex on HPB-ALL transformed T cells. This interaction may provide a bridge by which events related to ligand binding to Ti(TcR)/CD3 may trigger T cells via the CD4/CD8:p56lck complex.

Preoperative NT-proBNP and CRP predict perioperative major cardiovascular events in non-cardiac surgery.

OBJECTIVE: To investigate whether simple and non-invasive measurement of N-terminal pro-brain natriuretic peptide (NT-proBNP) and/or C-reactive protein (CRP) can predict perioperative major cardiovascular event (PMCE). DESIGN: Prospective, single-centre, cohort study. SETTING: A 1900-bed tertiary-care university hospital in Seoul, Korea Design and PATIENTS: The predictive power of NT-proBNP, CRP and Revised Cardiac Risk Index (RCRI) for the risk of PMCE (myocardial infarction, pulmonary oedema or cardiovascular death) were evaluated from a prospective cohort of 2054 elective major non-cardiac surgery patients. Optimal cut-off values were derived from receiver operating characteristic curve (ROC) analysis. MAIN OUTCOME MEASUREMENT: PMCE (myocardial infarction, pulmonary oedema or cardiovascular death) within postoperative 30 days. RESULTS: PMCE developed in a total of 290 patients (14.1%). Each increasing quartile of NT-proBNP or CRP level was associated with a greater risk of PMCE after adjustment for traditional clinical risk factors. The relative risk (RR) of highest versus lowest quartile was 5.2 for NT-proBNP (p<0.001) and 3.7 for CRP (p<0.001). Both NT-proBNP (cut-off = 301 ng/l) and CRP (cut-off = 3.4 mg/l) predicted PMCE better than RCRI (cut-off = 2) by ROC analysis (p<0.001). Moreover, the predictive power of RCRI (adjusted RR = 1.5) could be improved significantly by addition of CRP and NT-proBNP to RCRI (adjusted RR 4.6) (p<0.001). CONCLUSIONS: High preoperative NT-proBNP or CRP is a strong and independent predictor of perioperative major cardiovascular event in non-cardiac surgery. The predictive power of current clinical risk evaluation system would be strengthened by these biomarkers.

The normal range and position of the pineal gland on computed tomography.

Precise measurements with the Vanguard Motion Analyzer were made to determine the position of the pineal gland as shown on the Polaroid displays of 145 normal scans. The relatively midline positions of the gland are expressed in terms of percentage shift of the gland in these 145 normal cases is defined by a mean value of 0.8% with a standard deviation of 0.6%. More than 99% of normal CT scans can be expected to show a percentage shift of 2.6% or less.