Cytokine Responses of Human Blood Monocytes Stimulated with Igs

Using an in vitro system for stimulating human peripheral blood mononuclear cells (PBMC) with immobilized Ig, patterns of cytokine production as a function of different Ig classes and subclasses were elucidated. Wells were coated with IgA, IgG1, IgG2, IgG3 or IgG4. Equivalent protein content on surfaces of wells was demonstrated by a human kappa chain ELISA. Isolated human PBMC were added to Ig-coated wells and incubated for 24 hrs before supernatants were assayed for cytokines. The IgG subclasses showed differences in cytokine production stimulated from PBMC, with the relative stimulation for TNFα being IgG2 ≥ IgG3 ≥ IgG1 > IgG4 and for IL-6 production, IgG2 ≥ IgG3 > IgG1 = IgG4. In contrast, the relative stimulation for IL-8 was IgG1 = IgG2 = IgG3 = IgG4. IgA caused less production of TNFα when compared to IgG2, but similar levels of IL-8. Such differences may have important implications in the pathogenesis of immune complex mediated diseases.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44518/1/10753_2004_Article_426087.pd

The implementation of a mobile problem-specific electronic CEX for assessing directly observed student—patient encounters

Background: Facilitating direct observation of medical students' clinical competencies is a pressing need. Methods: We developed an electronic problem-specific Clinical Evaluation Exercise (eCEX) based on a national curriculum. We assessed its feasibility in monitoring and recording students' competencies and the impact of a grading incentive on the frequency of direct observations in an internal medicine clerkship. Students (n=56) at three clinical sites used the eCEX and comparison students (n=56) at three other clinical sites did not. Students in the eCEX group were required to arrange 10 evaluations with faculty preceptors. Students in the second group were required to document a single, faculty observed ‘Full History and Physical’ encounter with a patient. Students and preceptors were surveyed at the end of each rotation. Results: eCEX increased students' and evaluators' understanding of direct-observation objectives and had a positive impact on the evaluators' ability to provide feedback and assessments. The grading incentive increased the number of times a student reported direct observation by a resident preceptor. Conclusions: eCEX appears to be an effective means of enhancing student evaluation

PBMC cytokine production following stimulation by IgG subclasses or IgA: Implications for TNF-alpha and IL-8 pathways.

Many immune complex diseases are associated with deposits of specific immunoglobulin (Ig) classes and subclasses. Using an in vitro system for stimulating human peripheral blood mononuclear cells (PBMC) with immobilized Ig, patterns of cytokine production as a function of different Ig classes and subclasses were elucidated. Wells were coated with IgA, IgG1, IgG2, IgG3 or IgG4. Equivalent protein content on surfaces of wells was demonstrated by an ELISA for human kappa chain. Isolated human PBMC were added to Ig-coated wells and incubated for 24 hrs before supernatants were collected and assayed for cytokines by ELISA. The IgG subclasses showed differences in cytokine production stimulated from PBMC, with the relative stimulation for TNF a being IgG2 ≥ IgG3 ≥ IgG1>IgG4 and for IL-6 production, IgG2 ≥ IgG3>IgG1=IgG4. In contrast, the relative stimulation for IL-8 was IgG1=IgG2=IgG3=IgG4. IgA caused substantially less production of TNF a when compared to IgG2, but similar levels of IL-8 were produced. Such differences may have important implications in the pathogenesis of immune complex mediated diseases. The above results suggested that PBMC production of TNF a and IL-8 proceed via different signal transduction pathways. To investigate this possibility, inhibitors of second messenger systems were used to evaluate TNF a and IL-8 production. PBMC were pretreated with inhibitors before adding the cells to IgG2-coated wells. After 4 hr, supernatant fluids were evaluated. The inhibitors of protein kinase C (PKC) completely inhibited TNF a production while having no effect on IL-8 production. Go6976 (an inhibitor specific for Ca++-dependent isoforms of PKC) inhibited generation of both TNF a and IL-8, suggesting different isoforms of PKC may have opposing effects on IL-8 production. Inhibitors of protein tyrosine kinases and phospholipase C inhibited both TNF a and IL-8 production, suggesting that both components are involved in cytokine production. Further, inhibitors of G proteins had differing effects. Pertussis toxin, which affects inhibitory G proteins, significantly inhibited IL-8 but not TNF a production, while cholera toxin, an inhibitor of stimulatory G proteins, significantly inhibited TNF a but not IL-8 production. These findings provide evidence for distinct signaling pathways of cytokine production from PBMC stimulated by immobilized Ig's.Ph.D.Health and Environmental SciencesImmunologyPathologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/131647/2/9929823.pd

Empathy in Internal Medicine Residents at Community-based Hospitals: A Cross-sectional Study

Introduction: Many research reports revealed declining empathy in medical schools that continues in postgraduate years of training. Objective: The aim of this study is to examine the self-reported empathy levels of internal medicine (IM) residents in 3 community-based teaching hospitals. Methods: The Jefferson Scale of Physician Empathy, Health Professionals version, is an online, self-administered, questionnaire that was offered to 129 current and incoming residents at 1 osteopathic and 2 allopathic, IM training programs in Flint, Michigan. Results: Forty-five residents responded (35% response rate). Our residents’ cumulative mean empathy score was 112.5 with a SD of 12.72, which is comparable with the cumulative empathy scores for IM residents at university hospitals. There was an increase in empathy score from the beginning level of training, postgraduate year 0 (PGY0), to the PGY1 level, and a noticeable, although statistically non-significant, decrease in empathy score for both PGY2 and PGY3 residents. The graduating residents’ scores were higher compared with incoming residents. Conclusions: The cumulative mean empathy score in community-based IM residents showed an increase in the beginning of residents’ training and decrease in empathy score by the end of training. There were significant differences in empathy scores by level of training at individual hospitals. This might be related to different targeted curricula

æFEATURE ARTICLE

The implementation of a mobile problem-specific electronic CEX for assessing directly observed student patient encounter

Blood mononuclear cell production of TNF‐α and IL‐8: engagement of different signal transduction pathways including the p42 MAP kinase pathway

Recent studies of human peripheral blood mononuclear cells (PBMC) stimulated with IgG subclasses have suggested that tumor necrosis factor α (TNF‐α) and interleukin‐8 (IL‐8) production proceed along different signal transduction pathways. To investigate this possibility, inhibitors of signal transduction pathways were employed. Human PBMC were pretreated with various inhibitors before being added to IgG2‐coated wells and 4‐h supernatant fluids evaluated for cytokine content. The effects of various inhibitors on MAP kinase activation were determined. Inhibitors of protein tyrosine kinases, phosphatases, and phospholipase C decreased TNF‐α and IL‐8 production, suggesting that all three enzyme pathways are involved in cytokine generation. Inhibitors of G‐proteins had differing effects: pertussis toxin inhibited IL‐8 but not TNF‐α production, whereas cholera toxin inhibited TNF‐α but not IL‐8 production. Pretreatment of PBMC with pertussis toxin resulted in reduced IgG2‐induced calcium mobilization, whereas cholera toxin had no effect, correlating with the effects of pertussis toxin on IL‐8 expression. Inhibitors of protein kinase C (PKC) completely blocked TNF‐α generation but had no effect on IL‐8 production. Gö6976, which inhibits certain isoforms of PKC, inhibited production of both IL‐8 and TNF‐α. Isoforms of PKC may have opposing effects on cytokine production. PD 98059, a compound that specifically inhibits the activation of mitogen‐activated protein kinase kinase (MEK1), inhibited TNF‐α production, but had insignificant effects on IL‐8 production. Pretreatment of PBMC with either PD 98059 or genistein reduced the extent of phosphorylation of p42 MAP kinase in cells activated on contact with IgG2. These findings suggest distinct signal transduction pathways for cytokine production in PBMC stimulated with IgG2. J. Leukoc. Biol. 64: 124–133; 1998.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141323/1/jlb0124.pd