Experiencing virtual patients in clinical learning: a phenomenological study

Computerised virtual patients (VPs) are increasingly being used in medical education. With more use of this technology, there is a need to increase the knowledge of students’ experiences with VPs. The aim of the study was to elicit the nature of virtual patients in a clinical setting, taking the students’ experience as a point of departure. Thirty-one students used VPs as a mandatory part of an early clinical rotation in rheumatology. Using the qualitative approach of phenomenology, we interviewed these students and then analysed data regarding their experiences of VPs as a learning activity. The result shows that students perceived VP activities in relation to actual patients, the clinical context and other learning activities. The VPs represented typical clinical cases which encouraged clinical reasoning and allowed for decision making. The students experienced the activities as integrating biomedical knowledge and clinical experience, providing structure that prepared for the unstructured clinical environment and patient encounters under unstressful conditions. However, the VPs were experienced as lacking the emotional interactivity and complexity of actual patients. Theoretical frameworks of clinical reasoning and experiential learning are suggested as foundations for further educational integration of VPs in the clinical environment. VP activities during clinical rotations provide experiences of clinical reality and allow students to solve problems actively. These features are dependent on VP technology but are also contingent on the surrounding environment.     

Two-pore channel protein TPC1 is a determining factor for the adaptation of proximal tubular phosphate handling

Aim

Two-pore channels (TPCs) constitute a small family of cation channels expressed in endo-lysosomal compartments. TPCs have been characterized as critical elements controlling Ca²⁺-mediated vesicular membrane fusion and thereby regulating endo-lysosomal vesicle trafficking. Exo- and endocytotic trafficking and lysosomal degradation are major mechanisms of adaption of epithelial transport. A prime example of highly regulated epithelial transport is the tubular system of the kidney. We therefore studied the localization of TPC protein 1 (TPC1) in the kidney and its functional role in the dynamic regulation of tubular transport.

Methods

Immunohistochemistry in combination with tubular markers were used to investigate TPC1 expression in proximal and distal tubules. The excretion of phosphate and ammonium, as well as urine volume and pH were studied in vivo, in response to dynamic challenges induced by bolus injection of parathyroid hormone or acid–base transitions via consecutive infusion of NaCl, Na₂CO₃, and NH₄Cl.

Results

In TPC1-deficient mice, the PTH-induced rise in phosphate excretion was prolonged and exaggerated, and its recovery delayed in comparison with wildtype littermates. In the acid–base transition experiment, TPC1-deficient mice showed an identical rise in phosphate excretion in response to Na₂CO₃ compared with wildtypes, but a delayed NH4Cl-induced recovery. Ammonium-excretion decreased with Na₂CO₃, and increased with NH₄Cl, but without differences between genotypes.

Conclusions

We conclude that TPC1 is expressed subapically in the proximal but not distal tubule and plays an important role in the dynamic adaptation of proximal tubular phosphate reabsorption towards enhanced, but not reduced absorption.