PII: S0307-4412(96)00126-4

Teaching Biochemistry to Medical Technology Students

BENITO GOMEZ-SILVA, ALDO ALVAREZ and ALEX QUAAS

Biochemistry Group Biomedical Department Health Sciences Faculty Universidad de Antofagasta P 0 Box 170, Antofagasta, Chile

Introduction The Medical Technologist is a professional prepared to propose, set up, execute and supervise techniques related to clinical chemistry, microbiology, parasitology, hema- tology and blood banks, at public and private medical centers in Chile. Nearly 100 new medical technologists (MTs) graduate each year f rom six Chilean universities. Universidad de Antofagasta, the only member of the public university system in Antofagasta, has been preparing this type of professional for more than 30 years. Here, we intend to present a description on how Bio- chemistry is dealt with in the training of MTs at Univer- sidad de Antofagasta and on course organization and teaching strategies.

The MT curriculum This course comprises 50 courses, distributed in 10 semes- ters, as 16-week courses. According to their content and training objectives, these are classified as general, basic, and professional courses. During the first five semesters, M T students take 25 basic courses, with a total of 113 academic hours, representing nearly 35% of the total load. Biochemistry is considered a basic discipline with two courses at the third and fourth semester levels (Table 1).

Laboratory activities in Biochemistry I and II Lab work is an essential feature in these courses, pursuing training benefits for the student, and an important number of hours are allocated to this activity, particularly during the second course. In Biochemistry I, the student receives and works with written lab guides, given in advance, containing short summaries on the chemical and biological principles involved in each lab activity, along with organized protocols to be followed. The lab sessions start with a 20-30min oral introduction, where the object- ive(s) to be reached and the various stages of the work to be done, are emphasized by the instructor. Depending upon the activity planned, the student may spend some time on calculations before starting the work (eg the required dilution of the 'unknown concentrat ion' solution in order to fall into the concentrat ion range of the technique, based on information given by the instructor). Students are organized into groups of 2-3, and each group carries out the designated experiments. No more

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than 20 students and two instructors participate in each lab session. At the end of a lab session, one group is assigned the recovery of the results obtained by all groups, to organize them and to give, on a planned date, a graded 30-40 min oral presentat ion (seminar), and will try to answer questions raised by the class and the instructor. Two or three seminars are put together in one lab session 1 week before a programmed lab written test. Spectro- photometr ic techniques are central on this first course, a decision taken after considering the requirements for the next professional courses, but also the professional profile and the type of regular work the graduated MT carries out at medical center laboratories. Thus, emphasis is put on theoretical aspects of light absorption, the role of each component on a reaction mixture, the chemical basis of the technique used, and on how to organize protocols. The lab work on the second Biochemistry course empha- sizes personal and team work. Each group of 3 -4 students receives an experimental problem to be solved. By reviewing the literature and in discussion sessions with the instructor, the group sets the experimental limits on the problem proposed, considering the availability of reagents and equipment. The group proposes experimental proto- cols and, once these are approved, they start the prepara- tion of solutions and the biological and lab materials they require. During the following sessions, the group carries out the experiments under the coordination and guidance

Table 1 Basic courses on the Medical Technology curriculum at Universidad de Antofagasta, Chile

Course Hours per week

Lecture Laboratory

First Semester Anatomy 2 3 Cell Biology 2 3 Inorganic Chemistry 2 4 Math I 3 - - Physics I 4 - - Second Semester Histology 4 - - Infirmary 2 1 Math II 2 3 Physics II 3 - - Physiology I 2 3 Public Health I 2 - - Organic Chemistry 2 4 Third Semester Biochemistry I 3 4 Genetics 3 - - Physiology II 3 - - Physiopathology I 2 2 Psychology 2 - - Public Health II 2 - - Statistics 3 - - Fourth Semester Biochemistry II 4 9 Immunology 2 3 Microbiology I 2 3 Parasitology I 2 2 Physiopathology II 2 2 Psychology II 3 - - Fifth Semester Methodology for Research 2 2

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Table 2 Some topics considered in the Biochemistry laboratory activities at Universidad de Antofagasta, Chile

Biochemistry I Biochemistry H

Absorption spectra Calibration curves Enzime kinetics Phosphate, glucose, protein,

nucleic acids concentration measurements

Chemical properties of aminoacids

Physical and chemical properties of proteins in solution

Protein separation by column chromatography and SDS-PAGE

Isolation and purification of amino acids

Isolation and purification of DNA, RNA and/or plasmids

Isolation and purification of enzymes

Enzyme inhibitors studies Evaluation of vitamin content

of the instructor. The students will use photometric techniques and others not practiced during the first course (eg SDS-PAGE, centrifugation, column chromato- graphy, etc), gaining experience in planning experiments, protocol formulation, preparation and handling of reagents and data analysis and presentation. Each group will organize a lab session based on the problem they have solved; they will prepare and distribute a lab guide to the rest of the class, becoming the instructors on that session. Finally, in a programmed lab session, 1 week before a lab written test, the group will give a 60-min seminar on their own results, including those obtained by the class, along with two more seminars given by other groups. Some examples of lab topics included on these Biochemistry courses are given in Table 2.

Lecture contents and activities Biochemistry I is basically an orthodox treatment of the major subjects reviewed during the semester. These are: structure and function of amino acids and proteins; enzymes; metabolism of carbohydrates, lipids, amino acids, and proteins; structure and function of nucleic acids; and regulation of metabolism. Biochemistry II is centered on structure and function of proteins, enzymology and molecular biology. Some themes of these three areas, that are not included in the formal lectures, unless they are also key concepts, are reinforced with one assignment per group of 2-3 students, on which they prepare a short talk on the subject. In order to improve the learning effectiveness of this strategy, we decided during 1995 to incorporate modifications on the assign- ments, considering previously published ideas, 1"2 but also to approach an alternative strategy for teaching Biochemistry, that is, problem-based learning? We asked the students to write a 3-page essay and to arrange a simple but informative poster, as a complement to their talk. Also, the form on which the assignment was presented to the group was modified. Instead of being highly specific, the group received a short paragraph containing key elements on which the students could decide the subject matter by themselves (after a few meetings with the course coordinator) and how deep they should search in the available literature. The following are examples of the student's assignments:

• Cellular damage caused by UV irradiation must be urgently and efficiently repaired. Defects in some stage(s) o f the repair process can be observed in patients with Xeroderma pigmentosum.

• The first protocol for gene therapy in humans was approved in 1989. Retroviruses, as vectors for gene trans- ference, is one available alternative.

• Advances in Biochemistry and Molecular Biology are intimately related to the successful production of biotechnological goods, eg insufin and growth hormone.

• Molecular oxygen plays a vital role in cell metabolism. Oxygen transference from hemoglobin to myoglobin is a key process that must be executed with high efficiency.

Student assessment In Biochemistry I, the lab seminar accounts for 25% of the lab final grade, while in Biochemistry II, the lab work assigned to each group represents 30% of the lab final grade. The mean of three written tests, distributed along the semester, accounts for the remaining percentage for the lab final grade. Students will fail either course if they do not reach a minimum of 4.0, as the lab final grade (grade scale: 1.0-7.0). The final grade on the lecture part of Biochemistry I and II is the mean value of three written tests taken during the semester. However, the grade obtained at the Biochemistry II lecture assignment is incorporated with a 25% value. A final examination, that considers only matters seen at the lecture sessions, is compulsory to all students, in both courses, who passed the lab final grade requisite. The following equations are used to obtain the course final grade (CFG): CFG (Bio- chemistry I) = (LG × 0.6 + LABG x 0.4) x 0.6 + (EXG × 0.4) and, CFG (Biochemistry I I ) - ( L G x 0.5 +LABG x 0.5) x 0.6 + (EXG x 0.4), where, L G - lecture final grade, L A B G - I a b final grade, and EXG-examinat ion grade. The period 1991-5 has shown a student fail percentage mean of 28 and 22% on Biochemistry I and II courses, respectively, with an average of 39 students per course.

Final remarks The lab seminars have been well-accepted by students, since they are considered a good complementary way for preparing the lab written tests. Also, students adapted well to the modifications introduced on Biochemistry II lecture assignments, participating actively in narrowing down, according to their readings and interests, the main subject from the general paragraph assigned. They enjoyed the preparation of posters and expanded on explanations. Finally, the consistently higher percentage of failure at the Biochemistry I course can be partly attri- buted to the student's deficiency in grasping basic chemical concepts at previous courses.

References 1 Smith, C A, Dawson, M M, Head, M B and Jones, M J (1994) Biochem

Educ 22, 16-18 2 Mulimani, V H (1995) Biochern Educ 23, 32-34 3 Smith, C A, Powell, S C and Wood, E J (1995) Biochern Educ 23,

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