In 2002, an integrated basic science course was introduced into the Bachelor of Dental Sciences programme at the University of Queensland, Australia. Learning activities for the Metabolism and Nutrition unit within this integrated course included lectures, problem-based learning tutorials, computer-based self-directed learning exercises and practicals. To support student learning and assist students to develop the skills necessary to become lifelong learners, an extensive bank of formative assessment questions was set up using the commercially available package, WebCT. Questions included short-answer, multiple-choice and extended matching questions. As significant staff time was involved in setting up the question database, the extent to which students used the formative assessment and their perceptions of its usefulness to their learning were evaluated to determine whether formative assessment should be extended to other units within the course. More than 90% of the class completed formative assessment tasks associated with learning activities scheduled in the first two weeks of the block, but this declined to less than 50% by the fourth and final week of the block. Patterns of usage of the formative assessment were also compared in students who scored in the top 10% for all assessment for the semester with those who scored in the lowest 10%. High-performing students accessed the Web-based formative assessment about twice as often as those who scored in the lowest band. However, marks for the formative assessment tests did not differ significantly between the two groups. In a questionnaire that was administered at the completion of the block, students rated the formative assessment highly, with 80% regarding it as being helpful for their learning. In conclusion, although substantial staff time was required to set up the question database, this appeared to be justified by the positive responses of the students.

We have studied the inhibitory action of long-and short-chain fatty acids on hepatic glucose utilization in hepatocytes isolated from fasted rats. The rates of hepatic glucose phosphorylation and glycolysis were determined from the tritiated products of [2-'H] and [6-3H]glucose metabolism, respectively. The difference between these was taken as an estimate of the 'cycling' between glucose and glucose-6-phosphate. In the presence of 40 mM glucose this cycling was estimated at 0.68 pmol/min/g wet wt. Glucose phosphorylation was unaffected during palmitate and hexanoate oxidation to ketone bodies but glycolysis was inhibited. The rate of glucose cycling was increased during this phase to 1.25 pmol/min/g. Following the complete metabolism of the fatty acids, glycolysis was reinstated and cycling rates returned to control levels. Hepatic glucose cycling appears to be an important component of the glucose/fatty acid cycle.

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Rates of cycling between glucose and glucose 6-phosphate and between glucose and pyruvate, and the effects of these cycles on glucose metabolism, were compared in hepatocytes isolated from fasted normal or streptozotocin-induced diabetic rats. In diabetic hepatocytes the rate of glucose phosphorylation was 30% lower than that in normal hepatocytes, and there was a doubling of the rate of glucose/glucose 6-phosphate cycling. In addition, the rate of glycolysis was 60% lower in diabetic hepatocytes. This inhibition of glycolysis and stimulation of glucose/glucose 6-phosphate cycling appeared to be a consequence of the elevated rates of endogenous fatty acid oxidation observed in diabetic hepatocytes. The proportion of glycolytically derived pyruvate that was recycled to glucose was more than doubled in hepatocytes from diabetic rats compared with normal animals. This increase also appeared to be linked to the high rates of endogenous fatty acid oxidation in diabetic cells. As a consequence of the increased rates of both these cycles, 85% of all glucose molecules taken up by diabetic hepatocytes were recycled to glucose, compared with only 50% in normal hepatocytes. Glucose cycling is therefore likely to make a substantial contribution to the hyperglycemia of diabetes.