The effect of aerial parts of Echinacea on the circulating white cell levels and selected immune functions of the aging male Sprague-Dawley rat.

Echinacea is one of the most widely used over-the-counter herbal preparations that purport to "improve immune system function", especially when taken as a short course of therapy (6-8 weeks). Since many purchasers are older individuals, a double-blind, placebo-controlled study was performed to investigate whether Echinacea could affect total and differential white cell counts, phagocytic activity and interleukin (IL-2) levels in 12-month-old, healthy, male Sprague-Dawley rats when administered over an 8-week period. Echinacea (50 mg/kg of aerial parts) mixed with peanut butter or peanut butter alone was fed to 16 rats, which were receiving regular food and water ad libitum. Cell counts and immune functions were determined on rat tail vein blood on a weekly basis. Echinacea significantly increased circulating total white cell counts during the first 2 weeks of administration, and IL-2 levels during the final 5 weeks of the study period (p<0.05). Differential counts were altered during the entire 8-week study, with mononuclear cells significantly increased to the detriment of granulocytes (p<0.05). No such changes were observed in animals given peanut butter alone. No difference was observed in phagocytic function between animals given Echinacea or peanut butter alone. These studies suggest that aerial components of Echinacea affect both mononuclear cell levels and circulating IL-2 levels in older animals.

Development of a microbiology course for diverse majors; longitudinal survey of the use of various active, problem-based learning assignments.

Educators are increasingly being encouraged to use more active- and problem-based-learning techniques and assignments in the classroom to improve critical and analytical thinking skills. Active learning-based courses have been purported to be more time consuming than traditional lecture methods and for many instructors have therefore proven difficult to include in many one-semester science courses. To address this problem, a series of assignments was developed for use in a basic microbiology course involving sophomore-, junior-, and senior-level students from five different biology majors (environmental science, biology, biochemistry, premedicine, and physician assistant). Writing assignments included global, historical, and social themes for which a standardized grading format was established. Students also participated in a class debate in which the merits of the living microbial kingdoms were discussed, with only one kingdom being saved from an imaginary global catastrophe. Traditional lectures were facilitated by the use of a dedicated note packet developed by the instructor and specific for course content. Laboratories involved group analysis of mini-case history studies involving pathogenic microbes. Students' perceptions of the subject were assessed using an exit questionnaire sent to 100 of the 174 students who had taken the course during the 5-year time period. The majority of the 64 students who responded were sophomores (78%), in keeping with the target audience, and their perception of the course's challenge level was significantly higher (p < 0.03, 8.7) than their junior and senior counterparts (7.9). Students rated the most useful learning tools as case history studies (9.4) and the class debate (9.1), with the introduction of a dedicated microbiology links web page to the University website representing the sole component resulting in a statistically significant increase in students' perceptions of the importance of the course (p < 0.03).