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Biomedical subjects

C Arkin

Publications and source records attributed to C Arkin.

10 recordsLinked to original sources
PubMed1998

Effect of anticoagulation protocol on outcome in patients undergoing CABG with heparin-bonded cardiopulmonary bypass circuits.

BACKGROUND: We have demonstrated that the use of heparin-bonded cardiopulmonary bypass circuits (HBCs) combined with a lower anticoagulation protocol as an adjunct to an integrated blood conservation strategy decreases the incidence and magnitude of homologous transfusion and improves clinical outcome in patients undergoing primary coronary artery bypass grafting. It is not known whether it is the lower anticoagulation protocol that influences outcome in patients treated with HBCs. Furthermore, the thrombogenic risk of using lower anticoagulation with HBCs still is debated. METHODS: To answer these questions, a prospective randomized study was conducted in which 244 patients undergoing primary coronary artery bypass grafting were treated with HBCs and randomized to undergo either a full (activated clotting time, > 450 seconds) or a lower (activated clotting time, > 250 seconds) anticoagulation protocol. In addition to clinical outcome, levels of thrombin generation markers during and after cardiopulmonary bypass were assessed in a consecutive subset of 58 patients (full anticoagulation profile = 28, lower anticoagulation profile = 30) by measuring thrombin-antithrombin complexes and prothrombin fragment 1.2. Levels of these markers also were correlated with the activated clotting time during cardiopulmonary bypass. RESULTS: Preoperative and intraoperative risk profiles and other characteristics were similar in both groups, with more than 60% of patients undergoing nonelective operation. Compared with the full anticoagulation protocol group, patients in the lower anticoagulation protocol group were less likely to require blood products (24.2% versus 35.8%, respectively; p = 0.047) and received substantially fewer homologous donor units (0.50 +/- 0.92 versus 1.08 +/- 2.10 U, respectively; p = 0.005). Clinical outcomes were uniformly outstanding (but similar) in both treatment groups, with a modest reduction in the length of the hospital stay in the lower anticoagulation protocol group (5.26 +/- 1.23 versus 5.63 +/- 1.73 days, respectively; p = 0.05). The use of HBCs with a lower anticoagulation protocol was not associated with any adverse clinical events. Thrombin generation increased during cardiopulmonary bypass in both treatment groups, but was unrelated to the anticoagulation protocol or the activated clotting time (r2 = 0.03). No differences between the full and lower anticoagulation protocol groups were noted in the number of microemboli detected by transcranial Doppler analyses during cardiopulmonary bypass (n = 40) or in the postoperative neurologic and neuropsychologic outcomes (n = 30). CONCLUSIONS: This study definitively demonstrates that, when used appropriately, patients who are treated with HBCs and a lower anticoagulation protocol have a lower incidence and magnitude of homologous transfusion and are not at any added risk for clinical, hematologic (thrombin-antithrombin complex and fragment 1.2 measurements), or microscopic (transcranial Doppler analyses) thromboembolic complications or for neurologic or neuropsychologic deficits.

Aged↗
PubMed1996

Immunophenotypic identification of Sezary cells in peripheral blood.

Despite anecdotal literature that Sezary cells express the CD4+ CD7- immunophenotype, no formal validation has been published establishing the use of this immunophenotype for clinical or experimental purposes. Consequently, the only method presently available for Sezary cell identification is nuclear contour analysis, a labor-intensive procedure not generally available at most major medical centers. In this study, the accuracy of CD4+ CD7- subset quantitation for the identification of Sezary cells was examined. The study found that the percentage of CD4+ CD7- cells is elevated in many Sezary syndrome/MF patients relative to normal, healthy individuals. In addition, CD4+ CD7- enumeration correlates with enumeration by nuclear contour analysis in most patients (11 of 15) with elevated CD4/CD8 ratios. The CD4+ CD7- subset also correlates with the expression of other aberrant immunophenotypes, such as CD3low or CD4low. Lastly, CD4+ CD7- subset quantitation correlates with the number of clonal T lymphocytes, as measured using V beta-specific T-cell receptor monoclonal antibodies. The study found this method to be exceptionally accurate, with two caveats: (1) the absence of an expanded CD4+ CD7- subset in patients with a normal CD4/CD8 ratio is uninformative; and (2) in approximately 25% of patients with an elevated CD4/CD8 ratio, the Sezary cells are CD7+.

Antigens, CD7↗
PubMed1988

Effect of drawing blood specimens proximal to an in-place but discontinued intravenous solution. Can blood be drawn above the site of a shut-off i.v.?

To assess the effects of drawing blood specimens from a site proximal to an intravenous (IV) infusion line, 24 volunteers were infused with approximately 30 mL of 5% (w/v) dextrose in 0.9% (w/v) NaCl solution. Specimens were drawn proximal to the IV line, while the solution was infusing, and at 1, 2, and 3 minutes after discontinuance of the infusion and assayed for glucose, sodium, chloride, and red blood cell (RBC) count. Control samples were obtained simultaneously from the opposite arm to determine any residual or dilutional effects from the infusing solution. Statistical analysis using the paired sample t-test showed no significant difference of RBCs between arms at or beyond 1 minute. Statistical power analysis reveals that there is a 95% level of certainty that there is less than 1% dilution of the test arm specimen. Analysis of sodium and chloride levels showed no contamination of the test arm specimen at 1 minute, but glucose concentrations still showed an average elevation over control of 5% at 3 minutes. The authors concluded that the drawing of blood specimens proximal to an IV infusion, 3 minutes after its discontinuance, has a clinically negligable dilutional effect but substances present at relatively high levels in the infused solution may still be detected.

Adult↗
PubMed1988

Factor VIII assays. Assessment of variables.

Factor VIII assays are the most common specific coagulation factor assay performed in the United States. Interlaboratory proficiency studies have documented persistent problems with variation in results between laboratories. The Coagulation Resource Committee of the College of American Pathologists conducted a workshop to analyze variables that may affect performance of the one-stage factor assay. The results indicate that accuracy of the assay can be improved by uniform standardization of reference plasma samples and that reproducibility can be enhanced through appropriate choice of reagents and instruments. Optimizing performance of this assay should lead to more reproducible interlaboratory results.

Evaluation Studies as Topic↗
PubMed1987

Haematologic manifestations of the human immune deficiency virus (HIV).

A variety of haematologic abnormalities are associated with infection by HIV, the human retrovirus that is the primary aetiologic agent of the acquired immunodeficiency syndrome (AIDS). We have reviewed the haematologic findings in well-characterized cohorts of patients with AIDS, AIDS-related complex (ARC) and asymptomatic homosexual men at risk for this retrovirus. Anaemia, granulocytopenia and thrombocytopenia were found in increasing prevalence according to the severity of clinical disease associated with retroviral infection. Bone marrow aspirations and biopsies revealed frequent hypercellularity, dysplasia, plasmacytosis and lymphoid infiltrates. These marrow morphologic findings were strongly associated with anaemia and granulocytopenia. Review of transfusion records of patients with HIV antibodies revealed a 21% prevalence of a positive direct antiglobulin test. The pathophysiology of the observed haematologic abnormalities may involve direct retroviral infection of bone marrow progenitors, abnormal regulation of haematopoiesis and/or autoimmune phenomena.

AIDS-Related Complex↗
PubMed1984

Response of protein C and protein C inhibitor to warfarin therapy in patient with combined deficiency of Factors V and VIII.

The role of Protein C in combined factor V/VIII deficiency was examined by reducing the Protein C concentration using warfarin therapy in a patient with the combined deficiency. The factor VIII deficiency was like Hemophilia-A, with deficiency of VIII:C and VIII:C(Ag), but normal VIIIR:Ag and VIIIR:cof. The factor V deficiency was due to loss of the V antigen. During warfarin therapy the Protein C level was reduced, but concentrations of factors V and VIII did not change. Protein C Inhibitor was normal throughout. Thus combined factor V/VIII deficiency is not related to Protein C levels.

Adult↗
PubMed1984

Lack of utility of routine screening tests for early detection of peritonitis in patients requiring intermittent peritoneal dialysis.

A prospective study was undertaken to examine the clinical presentation of peritonitis in patients maintained on intermittent peritoneal dialysis and to determine the value of qualitative and quantitative dialysate cultures, gram stain, neutrophil counts, and a semi-quantitative leukocyte test strip for case detection. Seven cases of peritonitis developed among 30 patients who underwent 553 dialyses. In most cases, neutrophil counts, cultures, and leukocyte test strip determinations were done within 48 hours prior to the clinical onset of peritonitis and in all instances failed to provide clues for incipient infection. Peritonitis was associated with a dialysate neutrophil count of greater than 500/mm3 and leukocyte test strips were highly sensitive and specific for the detection of this quantity of neutrophils. A total of 16 dialysate cultures was positive in asymptomatic patients who did not have peritonitis. None of these patients subsequently developed peritonitis with the same organism. Dialysate gram stains, cultures, neutrophil counts or leukocyte test strips did not provide an early diagnosis of peritonitis and their use in the absence of symptoms is therefore not recommended.

Diagnostic Tests, Routine↗