Heparin-induced thrombocytopenia (HIT), and heparin-induced thrombocytopenia with thrombosis syndrome (MITTS), are immune-mediated complications of heparin therapy associated with significant morbidity and mortality. Although much has been learned about the pathophysiology of this syndrome, there are many difficult issues remaining for physicians involved in the daily care of the patient about the diagnosis, prevention, and treatment. To determine whether the earliest detection of HIT and heparin cessation impacted outcome, 116 consecutive patients at a single institution, with HIT diagnosed by platelet aggregometry, mere divided into groups by time to heparin cessation basted on daily platelet counts. Thrombocytopenia was defined in two ways: as a 50% decline from baseline and an absolute platelet count of less than 100 X 10(9)/L. The overall thrombosis rate was 39% and was predominantly venous, The mortality rate of 27% was similar in patients with both HIT and MITTS. Despite heparin cessation at less than 48 h from the onset of thrombocytopenia (mean 0.5 days), there were no differences in thrombosis or mortality when compared to patients with later heparin cessation (mean 4.3 days). In summary, early detection of HIT with heparin cessation is insufficient therapy for the management and treatment of MITTS, An alternative to this strategy in the treatment of patients with HIT is indicated.

During clinical trials with the thrombin inhibitor argatroban, appropriate methods for drug monitoring were identified. Treated patients presented interesting challenges for coagulation laboratory parameter testing in the presence of argatroban. These issues are reported here. Regarding the monitoring of argatroban, the aPTT and ACT were effectively used clinically for low (0-2.5 microg/mL) or high (1-15 microg/mL) doses of argatroban. However, system (reagent and instrument) differences were noted in the time-to-clot values. A clot-based assay using Ecarin as the activator (ECT, Ecarin clotting time) appeared to be useful for monitoring both low and high drug levels with less interference from other drugs or coagulation defects. Also identified were the chromogenic antithrombin assay that could directly quantify argatroban and an HPLC based assay that could specifically quantify argatroban and its metabolites. With regard to assay interference by argatroban, several important effects were observed. The presence of argatroban synergistically interfered with the INR for those patients treated with oral anticoagulants. However, a chromogenic based method was able to determine factor X levels as a monitor of the oral anticoagulation without effect from argatroban. A similar synergistic response on the aPTT with heparin and argatroban was observed. Patients receiving argatroban evaluated for potential coagulation abnormalities could not be tested with the routine functional (clot based) assays for fibrinogen, factor levels or protein C. Argatroban acted as an inhibitor in these assays, causing a dose-dependent false decrease of fibrinogen and factor levels, and a false increase of protein C. Using a chromogenic assay for protein C, values equal to those obtained by an immunologic assay were achieved. These issues will most likely hold true for all thrombin inhibitors.

One aim of this study was to determine the incidence of new radiographic pulmonary abnormalities during hospitalization after cardiac surgery. Another aim was to determine if such abnormalities are more common among patients who had left internal mammary artery (LIMA) grafting. The predictive value of radiographic abnormalities for clinically important pulmonary morbidity was also determined. The anteroposterior chest radiographs of 152 patients obtained by portable equipment were evaluated to determine the incidence of new postoperative radiographic pulmonary abnormalities such as atelectasis, consolidation, infiltrate, and pleural effusion. Clinically important pulmonary morbidity was defined as a delay in tracheal extubation or discharge from the hospital because of a pulmonary reason. Among the 89 patients who had LIMA grafting and left pleurotomy, there was an 88% incidence of left-sided pulmonary abnormalities; a 73% incidence of left-sided atelectasis; and a 55% incidence of left-sided effusion. Among the 63 patients who had saphenous vein grafting only and/or valvular surgery, the respective incidences were 68%, 54%, and 35%, which were lower (P ≤ 0.05) than those in the patients who had LIMA grafting. There was no significant difference in abnormalities between the saphenous vein grafting and the valvular surgery groups. The 35% incidence of left-sided pleural effusion when LIMA grafting and pleurotomy were not performed was unexpectedly high. There was no association between radiographic abnormalities and age, the duration of cardiopulmonary bypass, and the duration of aortic occlusion, indicating that cardiopulmonary bypass was not a primary etiology of these radiographic abnormalities. Among the patients who had LIMA grafting, pulmonary morbidity contributed to delayed extubation after surgery of one patient and delayed discharge from the hospital of three patients. Among the patients who did not have LIMA grafting, pulmonary morbidity delayed discharge of one patient from the hospital. In a large percentage of patients, chest radiography detected minor pulmonary abnormalities that were rarely associated with a worse clinical outcome after cardiac surgery. Radiographic abnormalities were significantly more common when LIMA grafting was performed.

The calcium-channel blockers have expanded the therapeutic choices of the practicing physician. The recent changes in the recommendations regarding first-line therapy in the treatment of essential hypertension have allowed the use of a variety of different antihypertensive agents to provide safe and effective therapy.

Journal Article ON THE COMULTIPLICATORS OF GROUPS OF UNITARY AND ANTIUNITARY OPERATORS Get access C. J. BRADLEY, C. J. BRADLEY Mathematical InstituteOxford Search for other works by this author on: Oxford Academic Google Scholar D. E. WALLIS D. E. WALLIS Mathematical InstituteOxford Search for other works by this author on: Oxford Academic Google Scholar The Quarterly Journal of Mathematics, Volume 25, Issue 1, 1974, Pages 85–99, https://doi.org/10.1093/qmath/25.1.85 Published: 01 January 1974 Article history Received: 19 May 1973 Published: 01 January 1974

For pt. I see ibid., vol. 3, no.3, 610 (1970). Tables of space-group representations now available are incomplete for those space groups which do not have the full symmetry of the Bravais lattice on which they are based. It is shown that this defect can be overcome without recourse to further tabulation for all space groups except Pa3(Th6). This particular space group is considered separately, and is shown to be exceptional in that alone out of all the 230 space groups it possesses two k-vectors, which are related by an operation of the holosymmetric point group, but whose groups of k possess small representations of different dimensionalities. Nor does the addition of time reversal remove this anomaly.

A description is given of a triple-axis spectrometer for use at the PLUTO reactor at AERE, Harwell. The specification of the instrument is outlined together with a discussion of the problems arising therefrom and the novel methods adopted to overcome them, including the use of gas pads to support the detector shield and a small data processor for instrument control.