Transfusion errors in New York State: an analysis of 10 years' experience.

BACKGROUND: While public focus is on the risk of infectious disease from the blood supply, transfusion errors also contribute significantly to adverse outcomes. This study characterizes such errors. STUDY DESIGN AND METHODS: The New York State Department of Health mandates the reporting of transfusion errors by the approximately 256 transfusion services licensed to operate in the state. Each incident from 1990 through 1998 that resulted in administration of blood to other than the intended patient or the issuance of blood of incorrect ABO or Rh group for transfusion was analyzed. RESULTS: Erroneous administration was observed for 1 of 19, 000 RBC units administered. Half of these events occurred outside the blood bank (administration to the wrong recipient, 38%; phlebotomy errors, 13%). Isolated blood bank errors, including testing of the wrong specimen, transcription errors, and issuance of the wrong unit, were responsible for 29 percent of events. Many events (15%) involved multiple errors; the most common was failure to detect at the bedside that an incorrect unit had been issued. CONCLUSION: Transfusion error continues to be a significant risk. Most errors result from human actions and thus may be preventable. The majority of events occur outside the blood bank, which suggests that hospitalwide efforts at prevention may be required.

RevM10-expressing T cells derived in vivo from transduced human hematopoietic stem-progenitor cells inhibit human immunodeficiency virus replication.

A key feature of the pathogenesis of human immunodeficiency virus type 1 (HIV-1) infection is the gradual loss of CD4-positive T cells. A number of gene therapy strategies have been designed with the intent of inhibiting HIV replication in mature T cells. As T cells are products of hematolymphoid differentiation, insertion of antiviral genes into hematopoietic stem cells could serve as a vehicle to confer long-term protection in progeny T cells derived from transduced stem cells. One such "cellular immunization" strategy utilizes the gene coding for the HIV-1 rev trans-dominant mutant protein RevM10 which has been demonstrated to inhibit HIV-1 replication in T-cell lines and in primary T cells. In this study, we used a Moloney murine leukemia virus-based retrovirus encoding a bicistronic message coexpressing RevM10 and the murine CD8-alpha' chain (Lyt2). This vector allows rapid selection of transgene-expressing cells as well as quantitation of transgene expression. We demonstrate that RevM10-transduced CD34-enriched hematopoietic progenitor-stem cells (HPSC) isolated from human umbilical cord blood or from granulocyte colony-stimulating factor-mobilized peripheral blood can give rise to mature thymocytes in the SCID-hu thymus/liver mouse model. The phenotypic distribution of HPSC-derived thymocytes is normal, and expression of the transgene can be detected by flow cytometric analysis. Moreover, we demonstrate that RevM10 can inhibit HIV replication in T cells derived from transduced HPSC after expansion in vitro. This is the first demonstration of anti-HIV efficacy in T cells derived from transduced human HPSC.

Sustained retroviral gene marking and expression in lymphoid and myeloid cells derived from transduced hematopoietic progenitor cells.

The expression of antiviral genes in human hematopoietic stem or progenitor cells has been proposed as a strategy for gene therapy of AIDS. To be successful, this strategy requires safe and efficient transfer of the therapeutic gene into hematopoietic cells and gene expression has to be maintained in HIV susceptible cells following differentiation. We have used retroviral vectors to transfer the gene for a transdominant inhibitor of HIV replication (RevM10) into CD34+ stem/progenitor cells isolated from human umbilical cord blood (UCB). Following transduction, cells were allowed to differentiate either in vitro in clonogenic assays and long-term stromal cell cultures or in human thymus implanted in immunodeficient scid/scid mice in vivo (SCID-hu). Following differentiation and expansion, multiple lineages of cells were shown to carry the transgene. A higher percentage of gene-marked progenitor cells (10-30% in most cases) were detected in methylcellulose colony assays and in long-term stromal cell cultures (1-5%). In contrast, gene-marked T cells derived from transduced CD34+ cells in a SCID-hu model were detected at an even lower frequency (0.01-1%). RevM10 RNA expression was detected in CD34+ cells immediately after transduction and was maintained after in vitro differentiation of those cells into CD14+ myeloid cells. In T cells, the RevM10-specific RNA was detectable by RT-PCR and also by semiquantitative RNase protection. These findings demonstrate that LTR-driven gene expression is sustained in relevant cells derived from retrovirus-transduced hematopoietic progenitor cells after extensive differentiation in vitro and in vivo and suggest that stringent in vivo, rather than in vitro assays, may be a better preclinical system to improve gene marking and expression in hematopoietic cells.

Hematopoietic potential of cryopreserved and ex vivo manipulated umbilical cord blood progenitor cells evaluated in vitro and in vivo.

The hematopoietic potential of cryopreserved and ex vivo manipulated umbilical cord blood (UCB) samples was evaluated in vitro and in vivo. Phenotypic analysis shows that approximately 1% of cord blood mononuclear cells express high levels of CD34 antigen on their surface (CD34hi), but none of a panel of lineage antigens (Lin-), suggesting that they are hematopoietic progenitor cells that have not yet committed to a specific lineage. Approximately 1% of CD34hi/Lin- cells are primitive hematopoietic progenitors that produce B lymphoid and multiple myeloid progeny for up to 7 weeks in stromal cell cultures. Twenty-one percent (+/- 13%) of CD34hi/Lin- cells also express low levels of the Thy-1 antigen and are threefold to fourfold enriched over CD34hi/Lin- cells in primitive hematopoietic potential as measured by long-term culture and phenotypic analysis. One-week liquid cultures of CD34-enriched UCB progenitor cells in the presence of interleukin (IL)-3, IL-6, and stem cell factor (SCF) results in a two-fold to threefold expansion of progenitors capable of reinitiating long-term stromal cell cultures. Only the CD34hi/Thy-1+/Lin- cell population was capable of maintaining progenitors with secondary transfer potential in long-term stromal cell cultures and is thus postulated to contain all of the primitive hematopoietic stem cells in UCB. The in vivo transplantation potential of UCB was also measured. Ex vivo manipulated UCB progenitor cells were used to engraft irradiated human thymus fragments implanted in severe combined immunodeficiency (SCID) mice. Thymic engraftment with >5% donor-derived cells and a normal CD4/CD8 distribution was observed in 19 of 23 tissues tested. UCB cells from in vitro expansion cultures engrafted with efficiencies comparable to nonexpanded cells. Similar results were obtained for UCB engraftment of human bone fragments implanted in SCID mice. In all cases, engraftment was achieved in competition with endogenous competitor stem cells and across major histocompatibility barriers. Taken together, this data demonstrates that human UCB is a rich source of multipotent hematopoietic progenitors that can be cryopreserved, enriched by physical methods, and expanded in a limited fashion without measurable loss of long-term culture or in vivo engrafting potential as measured in these assays.

Renovascular hypertension in moyamoya syndrome. Therapeutic response to percutaneous transluminal angioplasty.

Moyamoya ("puff of smoke") syndrome is a disease of children and young adults caused by fibromuscular dysplasia of the internal carotid and proximal cerebral arteries and is rarely associated with hypertension. We report a 34-year old woman with moyamoya syndrome who presented with symptomatic severe hypertension associated with unilateral renal artery stenosis. The patient underwent percutaneous transluminal angioplasty of the right renal artery with subsequent improvement in blood pressure control on reduced, and later, no antihypertensive therapy. This case illustrates that moyamoya syndrome may be an intracranial manifestation of a systemic arterial disorder. Renal artery stenosis may, in appropriate cases, be managed by percutaneous transluminal angioplasty.

Premature conclusions in the diagnosis of iron-deficiency anemia: cause and effect.

Case records of patients with iron-deficiency anemia were audited using a computer-based algorithm. In 24 of 35 cases, the diagnostic conclusion seemed unjustified and characteristic of premature closure, one of four recurring errors in diagnostic reasoning described previously. Premature closure appeared to originate from subjects at all levels of training, to be easily and unquestioningly accepted by other physicians, and to inappropriately condition diagnostic and therapeutic decisions. Heuristics and biases described by Tversky and Kahneman are considered as contributory factors and patient care and teaching implications are discussed.

An appraisal of goals for residency training in internal medicine.

The goals for residency training in internal medicine were assessed by faculty and house staff members at one university-based program using a 38-item questionnaire based largely upon American Board of Internal Medicine criteria. The respondents rated each item according to its ideal importance, its actual emphasis in training, and the respondents' degree of satisfaction with their own level of accomplishment for that item. Faculty and house staff members shared similar perceptions of ideal goals and actual emphases of training, with both groups rating clinical judgment, gathering data, and formulating problems as the most important. Both groups also tended to rate highly as ideal goals those items that they considered to be their own professional strengths and that reflected their current respective roles in medical training. This trend was the most apparent for faculty members in ratings of academic skills and for house staff members in ratings of technical proficiency and patient management skills. The tendency to idealize one's own professional role and strengths may inhibit needed changes in residency training.

Premature conclusions in diagnostic reasoning.

The purpose of the study reported here was to explore the characteristics of premature diagnostic conclusions in a group of physicians, medical students, and residents. When the subjects were asked to construct complete, precise problem lists from three case abstracts, premature closure occurred frequently, it could be recognized with good interrater reliability, and it seemed to appear with equal frequency regardless of the level of training.

Knowledge, realism, and diagnostic reasoning in a physical diagnosis course.

Two 20-item tests and a case problem were administered to 83 students in a physical diagnosis course. One test contained items related to the content of the case problem, and the other items related to the balance of the course content. Confidence scoring procedures yielded scores of both knowledge and realism on the two tests. The case problem determined the subject's ability to integrate clinical data into an accurate list of diagnoses and yielded scores reflecting incomplete assembly of clues into diagnoses (incomplete synthesis) and unjustified conclusions (premature closure). Reliability of the confidence-scored tests was significantly greater than the reliability on the same items scored as a single correct answer. Knowledge improvement scores on both tests (relevant and nonrelevant knowledge) were significantly correlated with errors of incomplete synthesis. The realism score correlated significantly with premature closures but only on the test where the item content was relevant to the case problem.

A novel action of insulin on phosphoprotein formation by mammary gland explants.

Studies on the induction of casein synthesis in competent daughter cells formed in mammary gland explants have revealed a new action of insulin. Treatment with prolactin, in the absence of insulin, is responsible for the formation of some polypeptides which are destined to become phosphoproteins, or for the formation of a unique protein-kinase, or both. In any case, insulin is required for participation of the prolactin-induced factor(s) in a protein-kinase reaction.