PubMed Health⌕ Search

Biomedical subjects

D E Hammerschmidt

Publications and source records attributed to D E Hammerschmidt.

At least 37 records · Page 2Linked to original sources
PubMed1995

Pancytopenia due to hemophagocytic syndrome as the presenting manifestation of babesiosis.

We present a case of hemophagocytosis during infection with the intraërythrocytic protozoan Babesia microti in a 47-year-old splenectomized renal allograft recipient. After therapy with clindamycin and quinine a relapse responded to atovaquone; durable remission was not achieved until trimethoprim/sulfa was added. We postulate the severity of our patient's syndrome was due to splenectomy and chronic immunosuppression. Babesiosis should be considered when immunocompromised patients develop pancytopenia.

Babesiosis↗
PubMed1994

Anthracycline-based therapy of de novo acute myeloid leukemia in adults: failure of first-cycle cytoreduction to predict second-cycle outcome.

During 1971-1988, 194 adults with de novo acute myeloid leukemia (AML) received initial therapy at the University of Minnesota with an anthracycline-based regimen. Seventy-two of the 194 required further chemotherapy and received a second cycle of the same or similar therapy; 63 of these 72 were evaluable. For each marrow, a tumor burden index (TBI) was calculated, as the product of the marrow cellularity and the proportion of malignant cells. For each patient, the decrement in TBI between the initial and day approximately 14 marrows was recorded. Patients who achieved second-cycle CR were comparable to those who did not in general descriptors; there was no difference between second-cycle CR achievers and nonachievers in the cytoreduction effected by the initial cycle of therapy (74.9% +/- 4.5% [sigma] versus 71.9% +/- 5.9%). We then stratified patients according to the first-cycle cytoreduction, asking if we could find a level that was reliably predictive of increased or decreased likelihood of achieving CR with cycle 2. We could not, despite testing at many centile cuts. Patients achieving a very "poor" degree of cytoreduction in cycle 1 were as likely to achieve CR with cycle 2 as were patients having a very "good" initial cytoreduction. We conclude that (1) first-cycle response is not a useful predictor of second-cycle outcome in anthracycline-based therapy of de novo adult AML; and (2) a "poor" response to cycle 1 does not therefore a priori indicate a change to a different regimen for cycle 2.

Acute Disease↗
PubMed1993

Behaviour of platelets and beta-thromboglobulin.

Platelet count, platelet aggregation responses, and plasma beta-thromboglobulin were assessed before and at intervals during each study dialysis. As expected, modest thrombocytopenia was observed following treatment with all dialysers, but Filtral showed the least effect. Concordantly, modest increases in plasma beta-thromboglobulin were observed with all devices except Filtral (caveat: the device also seems to adsorb beta-thromboglobulin). Interpatient variability was more striking for platelet aggregation responses, and made it difficult to discern patterns; however, aggregation in response to ADP was augmented during haemodialysis with the Filtral device, and blunted when the G120 M was employed. Differences between hollow-fibre and parallel plate devices with the same membrane material suggest that membrane geometry, manufacturing residues, membrane support, or potting materials may also contribute to platelet activation.

Adenosine Diphosphate↗
PubMed1992

Characterization of multiple quinine-dependent antibodies in a patient with episodic hemolytic uremic syndrome and immune agranulocytosis.

A 23-year-old woman experienced six distinct episodes of severe combined neutropenia and thrombocytopenia. At least one of the episodes was accompanied by hemodialysis-requiring acute renal failure and fragmentation hemolysis (hemolytic uremic syndrome [HUS]). In retrospect, all episodes were probably associated with the ingestion of quinine. Quinine-dependent antibodies to platelets, neutrophils, T lymphocytes, and red blood cells (RBCs) were detected in the patient's serum. By a monoclonal antibody antigen capture assay, the patient's serum contained IgG antibodies, which in the presence, but not absence, of quinine reacted with platelet glycoprotein (GP) complexes Ib/IX and IIb/IIIa, but not Ia/IIa. By immunoprecipitation assay, the serum, after addition of quinine, reacted strongly with an 85-Kd neutrophil membrane protein and weakly with 130- and 60-Kd moieties. Serum adsorbed with RBCs in the presence of quinine continued to react with platelets and neutrophils, and serum that was absorbed with platelets continued to react with neutrophils and RBCs, indicating that the antigenic targets were different on platelets, neutrophils, and RBCs. Since platelets and endothelial cells share some antigens, we tested patient serum for antibodies to human umbilical vein endothelial cells (HUVEC); no quinine-dependent antibodies to HUVEC were detected. However, her quinine-dependent antibodies not only bound to platelets and neutrophils, but also activated neutrophils. Thus, the patient's serum with quinine aggregated neutrophils, but neither agent alone caused activation. Moreover, the patient's serum with quinine (but not without) augmented the adherence of neutrophils to HUVEC. Treatment of the patient's serum with staphylococcal protein A removed the quinine neutrophil aggregation cofactor, suggesting it was due to IgG. In both neutrophil aggregation and adherence assays, decomplementation of the patient's serum markedly blunted its effect. Furthermore, the patient's serum failed to aggregate formalin-inactivated neutrophils, suggesting neutrophil activation, probably by activated complement, was necessary for aggregation and adhesivity to endothelium. We conclude that our patient's neutropenia, thrombocytopenia, lymphopenia, and anemia were due to quinine-dependent antibodies, and that these antibodies recognized epitopes that were different in the three target cell populations. We further suggest that HUS was likely secondary to the activation and adhesion of neutrophils to endothelium.

Adult↗
PubMed1992

Hemolytic anemia in protoporphyria: possible precipitating role of liver failure and photic stress.

Hemolytic anemia is not a common clinical feature in protoporphyria. In this report, we describe two patients in whom we have encountered severe hemolytic anemia. Both individuals had advanced hepatic disease as a complication of their porphyria and were undergoing orthoptic liver transplantation. The onset of hemolysis appeared to be related to the development of liver disease, and in both cases, the operative procedure acutely exacerbated the red cell destructive process. We suggest that liver involvement in protoporphyria may unmask hemolytic anemia, and that red cells in these individuals are hypersensitive to photooxidative stress, such as might occur during a prolonged operative procedure.

Adolescent↗
PubMed1992

Institutional Review Board (IRB) review lacks impact on the readability of consent forms for research.

Consent forms in research are a source of current and retrospective information for the subject, a "prompt" for the person who is obtaining consent, and a documentation of the "informed" consent process and its adequacy. Occasionally, these forms may be administered by inexperienced trainees or ancillary personnel, and thus stand virtually alone. Therefore, the forms must be inherently comprehensible to the subjects. To test whether this is the case, 65 new applications were randomly selected from 13 consecutive IRB agendas, and their consent documents were computer-analyzed (Flesch/Fry scoring) after correction for expected confounding features, such as lists, tables, and polysyllabic proper names and jargon. Mean U.S. school grade for 70% comprehension (Fry score) was 15.03 +/- 0.19 (standard error of the mean), implying readability by 37.4 +/- 1% of the U.S. adult population. In contrast, a consecutive sampling of 21 Ann Landers columns yielded a mean Fry score of 7.67 +/- 0.5 (p < 0.01; readable by 75 +/- 3%). Fifteen Reader's Digest articles yielded a mean Fry score of 9.95 +/- 0.65 (p < 0.01; readable by 59.1 +/- 3%), and 15 "Talk of the Town" columns from The New Yorker averaged a grade level of 13.3 +/- 0.83; p < 0.01; readable by 42.7% +/- 4.8%). No document was improved by more than one grade level by the IRB review process, and most were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Comprehension↗