Involvement of donor T-cell cytotoxic effector mechanisms in preventing allogeneic marrow graft rejection

Donor CD8 cells play a pivotal role in preventing allogeneic marrow graft rejection, possibly by generating cytotoxic effectors needed to eliminate recipient T cells remaining after the pretransplant conditioning regimen or by producing cytokines needed to support the growth and differentiation of hematopoietic stem cells. In the present study, we assessed the role of donor T-cell cytotoxic effector function as a mechanism for eliminating recipient CD8 cells that cause marrow graft rejection in mice. The ability to prevent rejection was minimally affected by the presence of a defect in Fas ligand binding or by the absence of granzyme B but was severely affected by the absence of perforin. Doubly mutant perforin-deficient, Fas ligand-defective CD8 cells were completely unable to prevent rejection. Our results indicate first that recipient CD8 effectors responsible for causing marrow graft rejection are sensitive to cytotoxicity mediated by both perforin- and Fas-ligand-dependent mechanisms, and second that donor T cells must have at least one functional cytotoxic mechanism to prevent allogeneic marrow graft rejection.     

Stages of acquisition and cessation for adolescent smoking: an empirical integration

Adolescent cigarette smoking acquisition and cessation were integrated into a single nine-stages-of-change continuum using the transtheoretical model of change framework. Findings in a high school student sample (n > 700) showed that a few of the never smokers were planning to try smoking, and half of the current smokers were contemplating quitting. More than half of former smokers were long-term quitters. The high pros of smoking scores assessing coping benefits of cigarettes were related to smoking acquisition and the high con (disadvantages) scores to long-term abstinence. Never smokers were most tempted to try smoking when they anticipated that smoking would help reduce negative and increase positive mood. Current and former smokers were tempted due to peer cigarette offers and negative mood. These temptations were significantly reduced among ex-smokers.     

Bone tumor radiograph review by pathologists prior to pathologic diagnosis: a receiver operator curve analysis of diagnostic utility

OBJECTIVE: To assess the performance of quick rescreening as an internal quality control for cervical smears previously screened as negative and to compare this method with clinically indicated rescreening of negative smears and with further 10% random rescreening. STUDY DESIGN: In a small-workload laboratory with many different types of indications for cytology, during a three-month period, all gynecologic cytology smears considered negative for significant findings (anything above atypical squamous cells of undetermined significance (ASCUS)/atypical glandular cells of undetermined significance (AGUS) in the Bethesda System) or inadequate were quickly rescreened using a 10 x objective. RESULTS: Of the total 2,188 smears processed, 164 (7.5%) were excluded from rapid review because they were positive on routine screening, and 2,024 cases were subjected to rapid rescreening: 1,925 (95.1%) cases were considered negative and 99 (4.9%) positive for significant findings; 58 of the latter were confirmed and 41 not confirmed by the cytopathologist's detailed examination. The 58 confirmed cases were classified as: 43 ASCUS/AGUS, 14 of low grade squamous intraepithelial lesion and 1 of invasive cancer. No cases of high grade squamous intraepithelial lesion were detected. CONCLUSION: Considering that the routine screening and internal quality control of the laboratory had detected 117 positive cases, the additional 58 represent a definite increase in the efficiency of a small-workload laboratory. In such a clinical setting, no additional case of a high grade lesion was detected by rapid rescreening. The increase in cost and time was considered very reasonable, and the method was incorporated as quality control for the laboratory. Clinically indicated rescreening of negative smears and random 10% rescreening after random rescreening did not add significantly to quality assurance.     

Modelling the malleus vibration as a rigid body motion with one rotational and one translational degree of freedom

Vibration of a set of points distributed along the manubrium of cat was measured with a heterodyne interferometer in response to sinusoidal acoustic signals. The observed motion did not fit pure rotation of the malleus around a fixed axis coinciding with the anterior mallar and posterior incudal ligament as is classically assumed. As a first approximation a model of motion consisting of a rotational and a translational component was used. At low frequencies the rotation is mostly predominant, but the situation may be entirely reversed at mid and high frequencies. The presence of a translation besides rotation was also found at some frequencies in the motion of the human malleus.