Fc receptors are required in passive and active immunity to melanoma

Effective tumor immunity requires recognition of tumor cells coupled with the activation of host effector responses. Fc receptor (FcR) gamma-/- mice, which lack the activating Fc gamma R types I and III, did not demonstrate protective tumor immunity in models of passive and active immunization against a relevant tumor differentiation antigen, the brown locus protein gp75. In wild-type mice, passive immunization with mAb against gp75 or active immunization against gp75 prevented the development of lung metastases. This protective response was completely abolished in FcR gamma-deficient mice. Immune responses were intact in gamma-/- mice because IgG titers against gp75 develop normally in gamma-/- mice immunized with gp75. However, uncoupling of the Fc gamma R effector pathway from antibody recognition of tumor antigens resulted in a loss of protection against tumor challenge. These data demonstrate an unexpected and critical role for FcRs in mediating tumor cytotoxicity in vivo and suggest that enhancement of Fc gamma R-mediated antibody-dependent cellular cytotoxicity by inflammatory cells is a key step in the development of effective tumor immunotherapeutics.     

Three-week hepatitis B vaccination provides protective immunity

To determine whether a 3-week hepatitis B (HB) vaccination could achieve protective immunity, 89 healthy non-immunized young adults received three doses of 20 micrograms each of HBs antigen (GenHevac B, Pasteur) and were randomly assigned to schedule A (n = 44): two doses at day 0, one dose at day 21; or schedule B (n = 45): one dose at days 0, 10 and 21. Seroprotection rates (anti-HBs > or = 10 mIU ml-1) for groups A and B respectively were: 23 and 40% at day 21; and 77 and 91% at day 82 (not significant). Anti-HBs geometric mean titres were higher in group B than in group A (p < 0.05) at days 21 (6.4 versus 3.8) and 82 (77.6 versus 33.5). One year after primary vaccination, the seroprotection rate remained as high as 90% in the vaccinees of group B; after boosting all vaccinees had protective levels of anti-HBs antibodies. Thus 3-week HB vaccination with GenHevac B allowed early and durable protective immunity.     

Heading judgments during active and passive self-motion

Previous studies have generally considered heading perception to be a visual task. However, since judgments of heading direction are required only during self-motion, there are several other relevant senses which could provide supplementary and, in some cases, necessary information to make accurate and precise judgments of the direction of self-motion. We assessed the contributions of several of these senses using tasks chosen to reflect the reference system used by each sensory modality. Head-pointing and rod-pointing tasks were performed in which subjects aligned either the head or an unseen pointer with the direction of motion during whole body linear motion. Passive visual and vestibular stimulation was generated by accelerating subjects at sub- or supravestibular thresholds down a linear track. The motor-kinesthetic system was stimulated by having subjects actively walk along the track. A helmet-mounted optical system, fixed either on the cart used to provide passive visual or vestibular information or on the walker used in the active walking conditions, provided a stereoscopic display of an optical flow field. Subjects could be positioned at any orientation relative to the heading, and heading judgments were obtained using unimodal visual, vestibular, or walking cues, or combined visual-vestibular and visual-walking cues. Vision alone resulted in reasonably precise and accurate head-pointing judgments (0.3 degrees constant errors, 2.9 degrees variable errors), but not rod-pointing judgments (3.5 degrees constant errors, 5.9 degrees variable errors). Concordant visual-walking stimulation slightly decreased the variable errors and reduced constant pointing errors to close to zero, while head-pointing errors were unaffected.     

Influence of environment on passive immunity in calves

Passive immunity in neonatal calves is influenced by environment. Placing newly born Holstein calves (108 head) in three different housing environments (shade, cooled shade, hutch) during hot weather produced differences in body temperature, serum cortocosteroids, immunoglobulin IgG1 concentrations, and mortality. Experimental design permitted examination of effects due to treatments, time, differences in colostrum, and climatic environment in an analysis of variance. Calves exposed to the hotter, less desirable environment responded by having a higher mortality, higher serum corticosteroid concentration, and lower serum immunoglobulin IgG1 at 2 and 10 days after birth. All of these were correlated. Calves that died had serum immunoglobulin IgG1 falling below the mean for all experimental calves.     

Effective and long-lasting immunity against the parasite Leishmania major in CD8-deficient mice

The results of earlier investigations that tested whether CD8(+) T cells are required in the defense against Leishmania major have been inconsistent. We used CD8-deficient mice to directly address this issue. After primary infection with L. major, CD8-deficient mice controlled the infection for over 1 year and mounted strong T helper 1 cell responses. Thus, CD8(+) T cells are not required for the long-term control of a primary infection with L. major.     

Cardiac output and blood pressure during active and passive standing

The present study was conducted to demonstrate immunohistochemically, the sites of c-fos protein expression in the brains of mice subjected to acute and chronic social defeat stress. To induce social stress, mice were placed in situations of species-specific intermale aggression either only once or five times at 24 h intervals. Two hours after the single or fifth defeat stress, many c-fos immunoreactive neurons were observed in a variety of brain regions including the limbic system and sensory relay nuclei. The c-fos immunoreactive neurons in the brains of acute defeat mice decreased in number with time and the c-fos staining pattern of acute defeat mice became indistinguishable from that of normal control mice by 24 h after the single defeat stress. In contrast, chronic defeat stress induced persistent c-fos expression in the forebrain and brainstem even 24 h after the fifth defeat stress. In the forebrain of chronic defeat mice, the olfactory bulb, cingulate cortex, hippocampus, entire hypothalamus, septal nuclei and the amygdaloid complex, except for the central nucleus, were labeled intensely with c-fos antiserum. In the lower brainstem, nerve cells with c-fos immunoreactivity were seen mainly in ascending and descending sensory relay nuclei relevant to auditory and vestibular transmission, epicritic sensation (gracile and external cuneate nuclei), pain inhibition (central gray and raphe nuclei), and viscerosensory transmission (solitary tract nucleus). The differences in c-fos expression among the normal control, acute and chronic defeat mice were evaluated by an enumeration of the immunopositive neurons within each brain nucleus examined, and they were confirmed subsequently by statistical analysis. There was little c-fos expression in the nucleus putamen, lateral, ventral and posterior thalamic nuclei, pretectal nuclei, medial geniculate nucleus, red nucleus, substantia nigra, cerebellum, spinal cord, or cranial nerve nuclei. These findings suggest that chronic but not acute defeat stress causes persistent c-fos expression in more widespread brain regions than do any other stresses so far investigated. The present study may shed light on the central mechanisms by which behavioral abnormalities and/or chronic sociopsychological stress leads to the occurrence of abnormal behavior and/or psychosomatic disorders in experimental animals and humans.     

Elaborative inferencing as an active or passive process.

E. J. O'Brien et al (see record 1988-31689-001) reported that readers generated elaborative inferences only when a text contained characteristics that virtually eliminated the possibility of an inference being disconfirmed. We reanalyzed O'Brien's data and also conducted an experiment in which we varied (a) whether or not there was an anaphoric relation between a target word and its prior mention in the text and (b) the explicitness of the prior mention. Two refinements to O'Brien et al's conclusions are offered. First, the two text characteristics they manipulated (a strong biasing context or a demand sentence) may have produced different types of elaborative inferencing. We argue that a biasing context results in a passive form of elaborative inferencing, involving setting up a context of interpretation, whereas the presence of a demand sentence invites the reader to actively predict a subsequent expression. Second, clear evidence for either type of inference will be apparent only with truly anaphoric materials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of auditory P300 habituation from active and passive conditions

The P3(00) event-related brain potential (ERP) was elicited using auditory stimuli and tasks in which the subject discriminated between standard and target tones or with passive task conditions in which the subject did not respond to either the standard or target stimuli. All stimulus presentations consisted of a series of ten-tone sequences in which the first six tones were always the standard and one of the last four tones was the target. The passive tasks were presented twice to assess for habituation effects. P3 amplitude was largest for the oddball task compared to the passive tasks, and repetition of the passive paradigm demonstrated a decrease in amplitude between conditions. P3 amplitude did not decrease across trials within any of the separate response conditions. P3 latency was shorter for the active discrimination relative to the passive tasks. The results suggest that the P3 component can be obtained reliably with passive procedures and does not habituate within a trial block. However, repeated blocks of passive stimulus presentations will cause the P3 ERP to diminish in size.     

Breastfeeding and HIV

An assessment was done during 1991 to evaluate the quality of care with regard to mouth hygiene rendered to patients in a teaching hospital in Namibia. The sample was drawn from nine wards. By means of a type of quota sampling, the patients were categorised as dependent, interdependent or independent. The nursing process was used as a framework for the study. From the assessment it became evident that no policies existed with regard to oral hygiene. Planning was not in every case based on assessment, and it seemed that when planning(s) were done, it was not always implemented. Record keeping was the aspect most poorly attended to.     

Evidence for active and passive urate transport in the rat proximal tubule

Studies utilizing the technique of simultaneous microperfusion of peritubular capillaries and tubular lumen of the proximal tubule of the rat were performed to determine if the absorption of urate was an active transport process and to determine the passive permeability coefficient for urate. When radioactive urate of equal specific activity and concentration was present in both perfusion solutions, the ratio of collected to initial concentrations of urate in the luminal perfusate (CO/CI) was 0.71 +/- 0.02. This gradient was higher than that predicted at equilibrium from the electrical potential difference determined in the in vitro perfused rabbit proximal tubule. The addition of para-chloromercuribenzoate (PCMB) to both solutions resulted in a significantly higher CO/CI of 0.90 +/- 0.02. This latter value is closer to the value predicted at electrochemical equilibrium. In separate studies, the unidirectional fluxes of urate were determined in the presence of PCMB. The calculated passive permeability coefficient averaged approximately 0.94 pmol . min-1 . mm-1 . mM-1 and was equal in both directions. These results indicate that in the rat proximal tubule urate absorption is an active transport process. In addition, there exists a passive permeation pathway for urate movement out of and into the proximal tubule.     

Hypnotic dissociation, dichotic listening, and active versus passive modes of attention.

Describes 2 experiments with 75 high and low hypnotically susceptible Ss (Harvard Group Scale of Hypnotic Susceptibility). Detecting left-channel targets interfered less with the shadowing of right-channel prose when performance of the former task was posthypnotically dissociated from consciousness. However, this superiority over an ordinary divided-attention condition was not due to unconscious target detection by Ss. Rather, the suggestions for posthypnotic responsiveness with amnesia apparently engendered a passive mode of attention to the left-channel task, such that Ss did not actively listen for targets in order to hear them. In Exp II, explicit instructions to adopt a strategy of attentional passivity to the target-detection task proved to be far more effective in producing the reduced-interference effect than the posthypnotic suggestions had been. The posthypnotic suggestions seemed to induce attentional passivity as an indirect effect of amnesia for the posthypnotic suggestions and for previously detected targets. Study findings are interpreted in terms of E. R. Hilgard's (1973) neodissociation theory. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Breastfeeding and shorter hospital stays

Contingent negative variation (CNV) was examined in 14 epileptic patients (5 with generalized and 9 with partial fits) both before and after 24 hours of sleep deprivation. Background CNV indices differed significantly by higher amplitudes of nearly all CNV components from the ones of healthy individuals. Amplitudes of postimperative negative waves (PINW) and general waves differed most of all. After sleep deprivation there was an PINW increase as well as the tendency to the late CNV component amplitude's increase. Elevation of CNV amplitudes after sleep deprivation was more pronounced in patients in which the deprivation provoked development of epileptic fits in comparison with patients which endured sleep deprivation rather favourably. The changes revealed in CNV components of the patients with epilepsy were considered in terms of disorders in regulatory mechanisms at the level of apical dendrites of cortical neurons' excitation.     

Breastfeeding twins and higher-order multiples

OBJECTIVE: To evaluate, in a pilot, open clinical trial on 40 patients with knee osteoarthritis, the structural changes in the synovial membrane and cartilage following treatment with intra-articular hyaluronic acid (HA-Hyalgan). METHODS: The structural effects of HA given as 5 weekly injections (20 mg/2 ml once a week for 5 weeks), were evaluated by microarthroscopy and morphological analysis of biopsy samples taken at baseline and after 6 months, under blind conditions. Clinical efficacy was also evaluated using visual analogue scales for pain and functional parameters. RESULTS: At 6 months, the microarthroscopic evaluation indicated that the majority of the patients (60%) showed no changes compared to baseline, while 32.5% of the patients showed improvement in the grading and/or extension of cartilage lesions and 7.5% showed a worsened condition. These changes were accompanied by a statistically significant reduction in the synovial inflammation (p = 0.001). The results were confirmed by morphological examination of the cartilage and synovial membrane. At 6 months compared to baseline, a statistically significant reconstitution of the superficial amorphous layer of the cartilage (p = 0.0039), an improvement in the chondrocyte density (p = 0.0023) and vitality (p = 0.05), and a statistically significant reduction in synovial inflammation (p = 0.0001) accompanied by a significant increase in the synovial repair process (p = 0.0001) were observed. Significant and long lasting improvement in pain and joint mobility were also seen after HA treatment. Joint effusion, when present, was reduced. The treatment was well tolerated. CONCLUSION: Hyalgan represents a useful therapy for knee OA, with long-lasting symptomatic efficacy and potential positive effects on joint tissues. Other studies, in particular placebo-controlled studies, are warranted to confirm these promising results observed on joint tissues.     

Comparison of active and passive manoeuvres on the pattern of airway closure in man

The effect of active and passive manoeuvres on closing volume was studied in conscious subjects. There were no significant differences in closing volume in nine of 10 non-smokers. There was a significantly greater closing volume with the passive manoeuvre (airway pressure +3 kPa to --2 kPa) in seven of nine smokers and one non-smoker with evidence of mild obstructive airway disease. The sensitivity of the closing volume to airway pressure could not be reproduced in three non-smokers exposed to a histamine aerosol. In two of three smokers the effect of airway pressure on closing volume was abolished by salbutamol. The results suggest that subjects with irritable airways may show an increase in closing volume with a change in airway pressure.     

Irreversibility of imprinting after active versus passive exposure to the object.

64 isolated Peking ducklings were reared for 4 days with a hanging colored object (passive training). Half of the Ss also received 3 1-hr following sessions with the object (active training). Findings indicate that both groups chose the imprinting object in a simultaneous choice test administered on Day 5, but the preference of active-trained Ss was more robust than of passive-trained Ss. Each S was then reared with an object of a different color and shape. The preference for the 1st object was maintained in active-trained Ss, but not in passive-trained Ss. These results were also found when the objects were removed from the cages for 4 days. Findings suggest that preferences established during the sensitive period for imprinting can be eliminated (but not necessarily reversed) in Ss that are prevented from following the original object, but they are resistant to change in Ss given the following experience. A hypothesis is presented that emphasizes the importance of reafference and activation of brain stem pathways involved in following the formation of specific affiliative bonds. (44 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)