Robert H. Levin

Assessing Clinical Skills of Residents with Standardized Patients

Current techniques do not provide a reproducible, reliable, or valid basis for assessing clinical skills. The need for large-scale direct observation and standardized assessment procedures has precluded development of better techniques. A project using standardized patients presenting with common clinical problems evaluated the skills of 336 internal medicine residents at 14 New England residency programs in 1289 standardized patient and resident encounters. Results indicated that reproducible assessment of the clinical skills could be achieved in approximately 1 day of testing time using standardized patients. Resident performance improved with years of training, and senior residents and those from programs with stronger reputations performed better and were more homogeneous in ability. Low correlations between standardized-patient-based measures of clinical skills and other evaluation techniques suggested that standardized patients provided unique information. Reactions of residents and faculty to standardized-patient-based evaluations were favorable.

Cytomegalic Inclusion Disease in Patients with Acute Leukemia

Excerpt Cytomegalic inclusion disease (CID), the result of infection with the salivary gland virus (SGV), has been reported frequently as a cause of morbidity and mortality in newborns and infants....

PERSISTENT MITOSIS OF TRANSFUSED HOMOLOGOUS LEUKOCYTES IN CHILDREN RECEIVING ANTILEUKEMIC THERAPY.

Temporary homologous bone marrow grafts were observed in three patients with acute leukemia, receiving intensive antileukemic treatment, following transfusion of peripheral blood cells from donors with chronic myelocytic leukemia. Persistent mitosis of the transfused cells, containing the Philadelphia chromosome marker, were detected by cytogenetic techniques 19, 39, and 52 days after transfusion.

Effect of Storage up to 48 Hours on Response to Transfusions of Platelet Rich Plasma

The effect of in vitro storage of platelet rich plasma (PRP) on the circulating platelet count following platelet transfusion was evaluated in patients with thrombocytopenia and acute leukemia. PRP was obtained by plasmapheresis using ACD anticoagulant. There was little or no decline in response to PRP up to seven hours after donation whether kept at room temperature or at 4 C. In order to study the effect of storage at 4 C. for 24 and 48 hours, a protocol was designed which limited donor‐patient variables. PRP stored 24 and 48 hours was 62 per cent and 37 per cent, respectively, as effective as fresh PRP in elevating the platelet count in the recipient one hour after transfusion.

Complement‐Fixing Platelet Iso‐Antibodies in Serum of Transfused Persons. Correlation of Antibodies with Platelet Survival in Thrombocytopenic Patients

Sera from 172 patients who had received an average of 34 transfusions per patient were assayed for platelet antibodies using a complement fixation technic. Fifteen patients formed a total of 31 antibodies. Eighteen of these were identified as reacting with six specific platelet antigens which were present in from 3 to 49 per cent of the general population. The antigens are common to leukocytes, but not erythrocytes, and are genetically determined. No antibodies were found in serum from 55 non‐transfused persons. The probability of antibody formation increased with repeated antigen exposure. Stored whole blood was at least as effective as platelet concentrates in provoking antibodies. There was a significant relationship between the presence of complement fixing platelet antibodies and the occurrence of “fever‐chill” transfusion reactions. In three patients it was possible to correlate the efficacy of platelet transfusion therapy with the antigen content of infused platelets.

Response to Transfusion of Platelets Pooled from Multiple Donors and the Effects of Various Technics of Concentrating Platelets

In order to determine the effect of concentration and pooling of platelet rich plasma (PRP) from multiple donors on response to platelet transfusion, the results of investigations with various preparations of fresh platelets for transfusion were analyzed. Transfusions of multiple donor, pooled PRP and platelet concentrates (PC) were compared by study of response to 385 transfusions in 55 patients with thrombocytopenia. The mean platelet increment an hour after PRP transfusion was 55,000/5 units/sq. meter surface area of the recipient. The mean fraction of platelets surviving in the circulation on the second day was 36 per cent of the increment. The results of the multiple donor pools were similar to PRP transfused from single donors. On the other hand, concentration of platelets reduced the effectiveness of platelet transfusion by over 50 per cent. Several methods of preparation of platelet concentrates were compared. The effects of age of the concentrate, resuspending medium, anticoagulant, and centrifugation are enumerated. However, a controlled clinical transfusion study showed that the decreased response to PC transfusions was due mainly to the deleterious effects of high speed centrifugation (1,500 to 5,000 × g) employed in the process of concentrating platelets from PRP. No method of preparing platelet concentrates was shown to be superior. Although inferior to PRP in terms of response to transfusion, concentrates are valuable because of their ease of handling and clinical utility when large quantities of platelets in a small volume of fluid are indicated.