Misconceptions, also known as alternate conceptions, about key concepts often hinder the ability of students to learn new knowledge. Concept inventories (CIs) are designed to assess students’ understanding of key concepts, especially those prone to misconceptions. Two-tiered CIs include prompts that ask students to explain the logic behind their answer choice. Such two-tiered CIs afford an opportunity for faculty to explore the student thinking behind the common misconceptions represented by their choice of a distractor. In this study, we specifically sought to probe the misconceptions that students hold prior to beginning an introductory microbiology course (i.e., preconceptions). Faculty-learning communities at two research-intensive universities used the validated Host-Pathogen Interaction Concept Inventory (HPI-CI) to reveal student preconceptions. Our method of deep analysis involved communal review and discussion of students’ explanations for their CI answer choice. This approach provided insight valuable for curriculum development. Here the process is illustrated using one question from the HPI-CI related to the important topic of antibiotic resistance. The frequencies with which students chose particular multiple-choice responses for this question were highly correlated between institutions, implying common underlying misconceptions. Examination of student explanations using our analysis approach, coupled with group discussions within and between institutions, revealed patterns in student thinking to the participating faculty. Similar application of a two-tiered concept inventory by general microbiology instructors, either individually or in groups, at other institutions will allow them to better understand student thinking related to key concepts in their curriculum.

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In this report, we describe an in vitro culture method for feline bone marrow cells, which yields large numbers of quiescent macrophages after 14 days of culture. The bulk of the cultured cell population consists of macrophages as assessed by morphology, macrophage specific cytochemistry, and phagocytosis. The remaining cells were lymphocytes, bone marrow stromal cells, fibroblasts and occasional polymorphonuclear leukocytes. While resting cells produced no detectable interleukin 1, stimulation with lipopolysaccharide (LPS) induced the production of biologically active interleukin 1. After 6 h LPS stimulation, mRNA for tumor necrosis factor alpha and interleukin 1 beta was detectable. The absence of mRNA in unstimulated cells indicates cultured macrophages were not activated until stimulated by LPS or plastic adherence. This approach provides a useful means to measure potential modulatory effects by virus infections or other agents upon feline macrophage gene expression.

Technetium-99m hexamethylpropyleneamine oxime (99"Tc-HMPAO) and Indium-111 oxine ("'Inoxine) labeled canine granulocytes were evaluated in vitro over a six hour period. Labeling efficiency for 99mTC-HMPA0 and "'In-oxine labeled granulocytes was 39.6% k 8.0% and 60.6% zk 17.6% (mean k SD) respectively. The mean in vitro elution of the radiolabel ranged from 8.7-14.0% for the 99mTc-HMPAO granulocytes and from 6.1-9.0% for the "'In-oxine granulocytes. Mean cell viability, for the 99"Tc-HMPA0, "'In-oxine and non-radiolabeled control granulocytes ranged from 97.&99.4%, 96.4-98.5% and 98.2-99.0%, respectively. The phagocytic ability of the 99mTc-HMPA0, "'In-oxine and control granulocytes ranged from 47.5-54.1%, 38.9-56.2% and 46.6-57.8% respectively over the six hour study period. Although labeling efficiency using '%-oxine was significantly (P = 0.05) better than 99"Tc-HMPA0, there was no significant difference in label retention of the two radiolabels. There was no significant difference in viability or phagocytic function during the six hour study period. Considering the potential cost advantage and the superior imaging qualities of Technetium-99m relative to Indium-111, 99"Tc-HMPA0 appears to be a good alternative to "'In-oxine as a granulocyte label.

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