Available evidence is inconclusive as to the ability of multiple choice items to measure different taxonomic levels of the cognitive domain. The present study analysed the tests of the Examen de Synthèse for the years 1982, 1983 and 1984. Items used in the study were those for which a consensus was reached between three judges and committees for a given taxonomic level. The initial part of the study showed that judges do not classify items at random but according to a mental representation which is individual, personal and relatively stable. In examining results obtained by students, the study failed to show any significant difference in item difficulty or discrimination for items classified as measuring memorization, interpretation of data and problem-solving. Correlations between results (scores and ranks) obtained for items involving memorization and those obtained for items involving higher cognitive levels fail to show that different traits are measured. If further studies corroborate these results, then future efforts should be directed at developing other instruments to measure higher cognitive levels.

The inactivation of synthetic [3H]thyrotrophin-releasing hormone (TRH) by plasma was studied in rats treated with propylthiouracil (PTU) alone or with PTU and thyroxine. 48 h after the onset of treatment with thyroxine, the capacity of rat plasma to inactivate [3H]TRH was significantly increased. The percentage of deamidation of TRH to TRH-free acid was increased 2-fold after 4 days of administration of thyroid hormone. The inactivation of TRH by plasma from hypothyroid patients was compared to that obtained from hyperthyroid patients. Extraction of human plasma incubated with [3H]TRH, followed by thin-layer electrophoresis, showed that transformation of [3H[TRH into TRH-free acid was 44% higher in plasma from hyperthyroid than from hypothyroid patients (P less than 0-05). These data suggest that the inactivation process of TRH by blood proteins could be an important factor in the regulation of the hypothalamo-hypophyseal-thyroid axis in rat and man.

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Dacron graft prostheses are routinely implanted to overcome impairment of arterial flow to distal tissues. Many different fabric configurations have been developped and evaluated. Unfortunately, after implantation the flow surface of any graft persists as a fibrinous lining. No human specimen has a commonly ingrown extension of tissue exceeding some millimeters in length. Full wall healing and endothelialization of arterial prosthesis is a goal that must be pursued intensively because it seems that the goal is attainable.