Studies on the absorptive defect for triglyceride in abetalipoproteinemia.

The nature of the gastrointestinal absorptive defect for triglyceride in three subjects with abetalipoproteinemia has been investigated by studying peroral biopsies of the gastrointestinal mucosa. The following conclusions were reached.1) In confirmation of other studies, the abnormal vacuoles within the duodenal absorptive cells of these individuals were lipophilic.2) On chemical analysis there was significantly more mucosal lipid than found in normal fasting specimens, and almost the entire increase was due to triglyceride.3) This excess mucosal lipid was reduced by a low fat diet, but even after 34 days on such a diet there was still an excess of lipophilic material near the villus tip and increased quantities of total lipid and triglyceride when compared with material from normal subjects similarly treated.4) Although there are demonstrable qualitative changes in mucosal and plasma lipids after an acute fat load, they are not quantitatively as great as in normal individuals. Fat balance studies and the qualitative changes in plasma and tissue lipids that do occur after more extended periods on different types of dietary fat do indicate that a considerable percentage of the dietary fat is assimilated. The route by which it is absorbed remains to be clarified.

Degradation of glycerophosphatides during storage of saline-washed, saline-suspended red cells at -20 degrees C.

When fresh intact red cells were washed and suspended in 0.153 M NaCl and then frozen-stored, the glycerophosphatide levels decreased significantly. Degradation began within 2 wk. Loss of phospholipid was not observed with hemoglobin-free red cell ghosts or plasma stored as long as 2 and 6 months, respectively.

Multiple strategies for studying medical clerkship experiences: a case study.

As part of a study reported here, the authors explored the utility of combining information generated by using various methodological approaches to study medical clerkship education. The clerkship consisted of two six-week rotations on two separate medical services. Three trained observers followed three third-year medical students for six consecutive days during the first and last week of each rotation. Observers went everywhere with students during each observational period, including 24-hour on-call days. The medical students also kept diaries of their daily experience during the study period. Diary data were combined with data from field observations and interviews to illustrate the enhanced understanding gained from a multiple-strategy approach.