Membrane receptors of mouse leukocytes. II. Sequential expression of membrane receptors and phagocytic capacity during leukocyte differentiation

Analysis of four mature cell markers on mouse bone marrow leukocytes grown in vitro, demonstrated a distinct sequence of marker appearance during the terminal phases of granulocytic cell differentiation. A similar pattern of marker expression was also suggested by analysis of mature neutrophils and macrophages isolated from normal tissues. Among cultured neutrophils, receptors for the Fc portion of IgG (FcR) were first expressed on myelocytes and metamyelocytes, and then subsequently on more mature cells. Morphologically mature colony neutrophils (polymorphs) from agar cultures contained only FcR and complement receptor type two (CR(2)) (C3d receptor), and lacked both complement receptor type one (CR(1)) (C3b receptor) and the capacity to ingest latex, bacteria, or iron particles. Neutrophils from 2 and 3 wk liquid media cultures of marrow cells differed from agar grown neutrophils in that they had phagocytic capacity (particle ingestion) [Pi] in addition to FcR and CR(2). Furthermore, in the 4th and 5th wk of these continuous liquid cultures, CR(1) was also expressed, completing the surface marker profile of normal blood neutrophils. Based on these studies, the following order of appearance of these four markers on cells from the myelocytic series was proposed: FcR {arrow} FcR CR(2) {arrow} FcR CR(2) Pi {arrow} FcR CR(2) Pi CR(1). Differential studies of tissue leukocytes containing these same markers revealed that a heterogeneity existed among morphologically mature neutrophils. Even though 95 percent of blood polymorphs contained all four markers, the same was true of only half of spleen polymorphs and only 20 percent of bone marrow polymorphs. Cells of the monocyte-macrophage series were studies in parallel with neutrophils. Cultured marrow monocytes acquired the four mature cell markers so rapidly that the order of receptor appearance could not be determined. However, it was found that CR2 was lost during the terminal phase of monocyte maturation into activated macrophages.     

Surfactant protein B deficiency: Clinical, histological and molecular evaluation

Congenital alveolar proteinosis due to surfactant protein B deficiency is an inherited disease which results in severe respiratory failure in term infants soon after birth. The pathophysiologic basis of this disease is now known to be an inability to synthesise adequate quantities of normally functioning surfactant protein B. We report a male infant with fatal respiratory failure of neonatal onset, and histopathological features typical of those seen in congenital alveolar proteinosis. Molecular analysis of genomic DNA revealed two mutations, the 'common' 121ins2 mutation in exon 4, and a novel 2bp frameshift mutation in exon 5. We believe this is the first Australian case of surfactant protein B deficiency confirmed by molecular analysis.     

Educators view people: Ethnic group stereotyping

Two hundred fifty-eight educators, 178 female and 80 male designated the words on the Gough Adjective Check List as being stereotypically associated with minority group members, dominant group members, or both. Adjectives on which 70 percent of all male and all female educators agreed were designated by society to either minority (N = 93) or dominant (N = 124) categories were used in eight of the ACL scales. Educators saw society as labeling dominant group members as significantly better adjusted, more achievement-oriented, more intraceptive and having more favorable characteristics than minority group members. Minority group members were seen as being viewed as significantly more aggressive than dominant group members. No significant differences were noted in the way society viewed the two groups regarding autonomous and deferent behavior. The results are discussed in terms of changes in stereotypes over the past fifty years and in terms of the effect of stereotyping on childrens' performance in school.     

The Efficacy of a Brief,Altruism-Eliciting Video Intervention in Enhancing COVID-19 Vaccination Intentions Among a Population-Based Sample of Younger Adults: Randomized Controlled Trial

BackgroundHigh COVID-19 vaccine uptake is crucial to containing the pandemic and reducing hospitalizations and deaths. Younger adults (aged 20-39 years) have demonstrated lower levels of vaccine uptake compared to older adults, while being more likely to transmit the virus due to a higher number of social contacts. Consequently, this age group has been identified by public health authorities as a key target for vaccine uptake. Previous research has demonstrated that altruistic messaging and motivation is associated with vaccine acceptance.ObjectiveThis study had 2 objectives: (1) to evaluate the within-group efficacy of an altruism-eliciting short, animated video intervention in increasing COVID-19 vaccination intentions amongst unvaccinated Canadian younger adults and (2) to examine the video’s efficacy compared to a text-based intervention focused exclusively on non-vaccine-related COVID-19 preventive health measures.MethodsUsing a web-based survey in a pre-post randomized control trial (RCT) design, we recruited Canadians aged 20-39 years who were not yet vaccinated against COVID-19 and randomized them in a 1:1 ratio to receive either the video intervention or an active text control. The video intervention was developed by our team in collaboration with a digital media company. The measurement of COVID-19 vaccination intentions before and after completing their assigned intervention was informed by the multistage Precaution Adoption Process Model (PAPM). The McNemar chi-square test was performed to evaluate within-group changes of vaccine intentions. Exact tests of symmetry using pairwise McNemar tests were applied to evaluate changes in multistaged intentions. Between-group vaccine intentions were assessed using the Pearson chi-square test postintervention.ResultsAnalyses were performed on 1373 participants (n=686, 50%, in the video arm, n=687, 50%, in the text arm). Within-group results for the video intervention arm showed that there was a significant change in the intention to receive the vaccine (χ²₁=20.55, P<.001). The between-group difference in postintervention intentions (χ²₃=1.70, P=.64) was not significant. When administered the video intervention, we found that participants who had not thought about or were undecided about receiving a COVID-19 vaccine were more amenable to change than participants who had already decided not to vaccinate.ConclusionsAlthough the video intervention was limited in its effect on those who had firmly decided not to vaccinate, our study demonstrates that prosocial and altruistic messages could increase COVID-19 vaccine uptake, especially when targeted to younger adults who are undecided or unengaged regarding vaccination. This might indicate that altruistic messaging provides a “push” for those who are tentative toward, or removed from, the decision to receive the vaccine. The results of our study could also be applied to more current COVID-19 vaccination recommendations (eg, booster shots) and for other vaccine-preventable diseases.Trial RegistrationClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT04960228","term_id":"NCT04960228"}}NCT04960228; https://clinicaltrials.gov/ct2/show/{"type":"clinical-trial","attrs":{"text":"NCT04960228","term_id":"NCT04960228"}}NCT04960228     

力竭性运动对大鼠血浆心钠素及心肌血供的影响

目的：观察不同训练程度大鼠力竭性运动后血浆心钠素含量及心肌缺血情况，探讨力竭性运动对大鼠心脏内分泌以及心肌血供的影响。方法：实验于2006—10/12在武汉体育学院细胞与分子生物学实验室完成。选择SD大鼠16只，按随机数字表法分为3组，安静对照组（n=4）笼内生活，自由饮食；游泳力竭组（n=6）适应性喂养1周后进行一定的适应性游泳训练；长期耐力训练游泳力竭组（n=6）训练8周，6次/周。8周后，后两组大鼠进行力竭性运动，运动后取大鼠血浆，采用放射免疫法测定心钠素含量；取心肌组织，制作光镜切片，采用Nagar-Olsen特殊染色法检测心肌缺血情况。结果：16只大鼠全部进入结果分析。①在经过8周的运动训练后，游泳力竭组、长期耐力训练游泳力竭组大鼠血浆心钠素含量显著高于安静对照组（P〈0．05，〈0．01）；长期耐力训练游泳力竭组大鼠血浆心钠素含量显著高于游泳力竭组（P〈0．05）。②游泳力竭组大鼠心肌组织缺血较为严重；而长期耐力训练游泳力竭组大鼠心肌组织与安静对照组相比，也有缺血现象发生，但没有游泳力竭组严重。结论：力竭性运动会造成大鼠心血管内分泌活性物质心钠素的失调，并造成心肌组织缺血；长期耐力游泳训练可以使大鼠心脏结构及功能产生一定的适应性改变。     

Effect of natural killer cells on syngeneic bone marrow: in vitro and in vivo studies demonstrating graft failure due to NK cells in an identical twin treated by bone marrow transplantation

Bone marrow transplantation for severe idiopathic aplastic anemia was undertaken in a patient, using his monozygotic twin brother as the donor. In spite of the use of syngeneic bone marrow, failure of engraftment occurred on two occasions. In vitro studies demonstrated that natural killer (NK) cells from the recipient markedly inhibited the growth of donor bone marrow granulocyte progenitor cells. On a third attempt, successful bone marrow engraftment was achieved following high-dose cyclophosphamide, which has previously been shown to be inhibitory to NK cells. We conclude that NK cell activity may play an important role in bone marrow failure as well as being responsible for at least some cases of aplastic anemia.     

Plasminogen activator inhibitor: a regulator of ancrod-induced fibrin deposition in rabbits

Plasma levels of a fast-acting plasminogen activator inhibitor (PAI), which neutralizes both tissue plasminogen activator (t-PA) and urokinase, are markedly increased in endotoxin-treated rabbits. The ability of this inhibitor to prevent the fibrinolysis that occurs after a thrombogenic stimulus was investigated in a rabbit model. Normal and endotoxin-treated male New Zealand rabbits were infused with ancrod, an enzyme that causes noncrosslinked fibrin formation in vivo. Ancrod stimulated t-PA activity by 90% in normal rabbits and caused hypofibrinogenemia but did not increase PAI levels or induce fibrin deposition in target organs. Rabbits injected with endotoxin (10 micrograms/kg) showed an increase in PAI from less than 1 to 32 U/mL 4 hours later. When ancrod was infused at this time, 90% of the rabbits developed renal fibrin thrombi. Fibrin deposition was recorded in 40% of the rabbits that received a lower dose of endotoxin (1.0 microgram/kg) and had a PAI level of 14 U/ml at the time of ancrod infusion 4 hours later. Fibrin deposition did not occur in the endotoxin-treated rabbits that received normal saline. These data suggest that high levels of PAI inhibit fibrinolysis in vivo, thereby promoting fibrin clot deposition following a thrombogenic stimulus.