Functional Analysis of B-L (Ia-Like) Antigen-Bearing Chicken Peripheral Blood Cells

The functional of B-L (Ia-equivalent)-positive (B-L+) adn -negative (B-L-) chicken peripheral blood lymphocytes (PBL) was studied in vitro and in vivo. The PBL were first stained in direct immunofluorescence tests with a fluorescein isothiocyanate-labelled anti-B-L alloantiserum and then separated by means of a fluorescence-activated cell sorter. In agreement with our previous findings, B-L- cells showed functional properties of T lymphocytes, responding to concanavalin A and phytohaemagglutinin-P in vitro and inducing a graft-versus-host (GVH) reaction when injected into allogeneic embryos. Sorted B-L+ gave no responses in any of these assays. Neither B-L+ nor B-L- cells, when tested alone, responded significantly to pokeweed mitogen, but mixtures of the two restored the responsiveness to that of the original unsorted suspension. Of the B-L+ PBL, 10% were T cells, which may account for the low GVH reactivity given by this population.     

Pulsed Shortwave Diathermy and Prolonged Long-Duration Stretching Increase Dorsiflexion Range of Motion More Than Identical Stretching Without Diathermy

OBJECTIVE: To compare the effects of 3 treatments on ankle dorsiflexion range of motion: prolonged long-duration stretching, pulsed shortwave diathermy followed by stretching, and pulsed shortwave diathermy, stretching, and ice combined. DESIGN AND SETTING: A 2 x 5 x 15 repeated-measures (on 2 factors) design guided this study. Range-of-motion change in triceps surae flexibility was the dependent variable. The 3 independent variables were treatment group, pretest and posttest measurements, and day. Treatment group had 4 levels: control, stretching (10 minutes of stretching via the weight and pulley), diathermy and stretching (20 minutes of diathermy and 10 minutes of stretching), and diathermy, stretching, and ice (20 minutes of diathermy, 10 minutes of stretching applied after 15 minutes of diathermy, and 5 minutes of ice applied during the last 5 minutes of stretching). Each subject received 14 treatments throughout 3 weeks, with a follow-up measurement taken 6 days after the last treatment. SUBJECTS: Forty-four healthy college-student volunteers not involved in any flexibility program. MEASUREMENTS: We measured ankle dorsiflexion using a digital inclinometer before and after treatment. RESULTS: After 14 days of treatment, the range-of-motion increase was greater after heat and stretching than after stretching alone. After 6 additional days of rest, the heat and stretching range-of-motion increase was greater than that for stretching alone. CONCLUSION: Pulsed shortwave diathermy application before prolonged long-duration static stretching was more effective than stretching alone in increasing flexibility throughout 3 weeks. After 14 treatments, prolonged long-duration stretching combined with pulsed shortwave diathermy followed by ice application caused greater immediate and net range-of-motion increases than prolonged long-duration stretching alone.     

Intestinal dendritic cells increase T cell expression of alpha4beta7 integrin

The integrin alpha4beta7 binds to MAdCAM-1 and contributes to homing of lymphocytes to gut and other mucosal tissues. In humans, the alpha4beta7(hi) subset of circulating memory cells appears to have been primed in mucosal tissues. The factors that determine whether alpha4beta7(lo) naive cells become alpha4beta(hi) or alpha4beta7(-) cells upon differentiation are poorly understood but could include an influence of the activating antigen-presenting cell. To address this point, the induction of alpha4beta7 following activation of mouse cells with the APC-dependent stimulus soluble anti-CD3 has been examined. Almost all mouse T cells freshly isolated from mesenteric lymph nodes (MLN) and peripheral (PLN; axillary, brachial and inguinal) lymph nodes stained only weakly for alpha4beta7 but a subpopulation became alpha4beta7(hi) upon activation with anti-CD3 in a cell cycle- and accessory cell-dependent manner. A small proportion (approximately 1.5 %) of the starting cells gave rise to alpha4beta7(hi) cells after culture. A higher proportion of alpha4beta7(hi) cells were generated in MLN than PLN cultures. Peyer's patch cultures gave intermediate values. In crossover experiments, MLN dendritic cells (DC) induced higher proportions and numbers of alpha4beta7(hi) cells than PLN DC irrespective of the source of T cells. Therefore, in addition to their other immunoregulatory roles, DC have the potential to shape immune responses by influencing the homing of the lymphocytes they activate.     

Stimulatory and suppressive effects of infection of dendritic cells with HIV-1.

Two effects of HIV infection on human dendritic cells (DC) in vitro have been examined. The first was the stimulation of primary responses to HIV antigens in autologous lymphocytes from normal donors. When DC were exposed to HIV (10(4) TCID/10(5) cells) for up to 24 h before addition to autologous lymphocytes, a marked primary proliferative response to the virus was observed. No proliferative response was seen when the period of pre-exposure of DC to virus was extended. Cytotoxic T cells specific for HIV-infected target cells developed in stimulated cultures. The second effect of HIV infection of DC was to block responses to other antigens, such as alloantigens and the recall antigens tetanus toxoid and influenza virus. This inhibitory effect was only evident when the DC were exposed to HIV for longer than 24 h before being added to cultures. These in vitro studies suggest that infection of DC can produce both stimulatory and inhibitory responses in lymphocytes. Such effects operating through DC might underlie in vivo activity of HIV both in stimulating the proliferation of lymphocytes (e.g., in persistent generalised lymphadenopathy) and in the development of immunosuppression.     

Direct and indirect memory performance in patients with senile dementia

The performance of patients with a presumptive clinical diagnosis of Senile Dementia of the Alzheimer's Type was compared to that of a group of normal elderly on several memory and neuropsychological tasks. The patients were impaired on tasks of free and cued recall, but exhibited normal performance on a word-completion procedure similar to that used by Graf et al. (1984). Reasons for the discrepancy between these findings and those from related research which reports impairment of word completion in patients with Alzheimer's Disease are discussed. Of particular interest is the role the orientating task plays in word-completion performance.