Stimulation of the antigen and interleukin-2 receptors on T lymphocytes activates distinct tyrosine protein kinases.

The T cell antigen receptor complex (TCR) and the interleukin 2 (IL-2) receptor are responsible for signal transduction that results in T lymphocyte activation and proliferation. Stimulation of either the TCR or the IL-2 receptor induces an increase in tyrosine phosphorylation of several cellular proteins indicating that signal transduction by both of these receptors involves the activation of a tyrosine protein kinase. Although the tyrosine protein kinases activated by these receptors have not yet been characterized the receptors themselves are known not to contain a tyrosine protein kinase domain.

The 75,000-dalton interleukin-2 receptor transmits a signal for the activation of a tyrosine protein kinase.

The high-affinity receptor for interleukin-2 (IL-2) is composed of two distinct subunits with molecular weights of 55,000 and 75,000 (p55 and p75). While the presence of the high-affinity receptor requires the simultaneous expression of p55 and p75, these subunits can also be expressed independently, resulting in IL-2 receptors with low and intermediate affinities, respectively. IL-2 can induce proliferation in cells expressing either the intermediate affinity p75 receptor or the p55.

Activation of a tyrosine protein kinase is an early event in the stimulation of T lymphocytes by interleukin-2.

The ability of the T lymphocyte growth factor interleukin 2 (IL-2) to activate a tyrosine protein kinase in vivo was assessed by using antibodies to phosphotyrosine in conjunction with immunoblots. Treatment of the murine IL-2-dependent cytotoxic T cell line CTLL-2 with IL-2 resulted in an increase in tyrosine phosphorylation of several proteins of molecular weights ranging from 38,000 to 120,000. The tyrosine phosphorylation in the various proteins increased in a concomitant fashion and reached a maximum level within 15 min.

Space-time behavior of single and bimanual rhythmical movements: data and limit cycle model.

How do space and time relate in rhythmical tasks that require the limbs to move singly or together in various modes of coordination? And what kind of minimal theoretical model could account for the observed data? Earlier findings for human cyclical movements were consistent with a nonlinear, limit cycle oscillator model (Kelso, Holt, Rubin, & Kugler, 1981) although no detailed modeling was performed at that time. In the present study, kinematic data were sampled at 200 samples/second, and a detailed analysis of movement amplitude, frequency, peak velocity, and relative phase (for the bimanual modes, in phase and antiphase) was performed. As frequency was scaled from 1 to 6 Hz (in steps of 1 Hz) using a pacing metronome, amplitude dropped inversely and peak velocity increased.

A qualitative dynamic analysis of reiterant speech production: phase portraits, kinematics, and dynamic modeling.

The departure point of the present paper is our effort to characterize and understand the spatiotemporal structure of articulatory patterns in speech. To do so, we removed segmental variation as much as possible while retaining the spoken act's stress and prosodic structure. Subjects produced two sentences from the "rainbow passage" using reiterant speech in which normal syllables were replaced by /ba/ or /ma/.

Head and neck cancer in the elderly.

One hundred fifty-nine patients, 80 years of age or older, with cancer of the head and neck were reviewed. Patients tolerated head and neck resection well and an absolute survival of 36 months for all treated patients and 41 months for all surgically treated patients suggests the efforts are worthwhile. Treatment offered the elimination of uncontrolled cancer in 68% of the patients.

Persistence of maternal antibody in infants beyond 12 months: mechanism of measles vaccine failure.

A serologic study was made in 34 children immunized against measles at the age of 12 months. Using a sensitive virus neutralization test, it was found that many of the children had pre-existing maternal antibody to measles virus. Children with high pre-existing antibody titers failed to seroconvert.