Louisa P. Colly

A Comparison of Real-Time Compression Ultrasonography with Impedance Plethysmography for the Diagnosis of Deep-Vein Thrombosis in Symptomatic Outpatients

BACKGROUND Impedance plethysmography performed serially over a one-week period has been shown to be an effective diagnostic strategy for patients with clinically suspected acute deep-vein thrombosis. Compression ultrasonography has a high sensitivity and specificity for the detection of proximal-vein thrombosis. The clinical value of repeated ultrasonography in the management of symptomatic deep-vein thrombosis is unknown. METHODS We conducted a randomized trial in 985 consecutive outpatients with clinically suspected deep-vein thrombosis to compare the diagnostic value of serial impedance plethysmography (494 patients) and serial compression ultrasonography (491 patients). We compared the positive predictive values of both tests for the diagnosis of venous thrombosis, using contrast venography as a reference. The frequencies of venous thromboembolism during a six-month follow-up period were also compared in patients with repeatedly normal results in order to evaluate the safety of withholding anticoagulant therapy from such patients. RESULTS The positive predictive value of an abnormal ultrasonogram was 94 percent (95 percent confidence interval, 87 to 98 percent), whereas the predictive value of impedance plethysmography was 83 percent (95 percent confidence interval, 75 to 90 percent) (P = 0.02). In patients with repeatedly normal results, the incidence of venous thromboembolism during the six-month follow-up period was 1.5 percent (95 percent confidence interval, 0.5 to 3.3 percent) for serial compression ultrasonography, as compared with 2.5 percent (95 percent confidence interval, 1.2 to 4.6 percent) for serial impedance plethysmography. CONCLUSIONS In making the diagnosis of deep-vein thrombosis in symptomatic outpatients, serial compression ultrasonography is preferable to impedance plethysmography, in view of its superior performance in detecting venous thrombosis.

Oral anticoagulation self-management and management by a specialist anticoagulation clinic: a randomised cross-over comparison

BACKGROUND Vitamin K antagonist treatment is effective for prevention and treatment of thromboembolic events but frequent laboratory control and dose-adjustment are essential. Small portable devices have enabled patient self-monitoring of anticoagulation and self-adjustment of the dose. We compared this self-management of oral anticoagulant therapy with conventional management by a specialist anticoagulation clinic in a randomised cross-over study. METHODS 50 patients on long-term oral anticoagulant treatment were included in a randomised controlled crossover study. Patients were self-managed or were managed by the anticoagulation clinic for a period of 3 months. After this period the alternative strategy was followed for each patient. Prothrombin time (expressed as international normalised ratio [INR]) were measured at intervals of 1-2 weeks in both periods without knowledge of type of management. The primary endpoint was the number of measurements within the therapeutic range (therapeutic target value +/-50.5 INR units). FINDINGS There was no significant difference in the overall quality of control of anticoagulation between the two study periods. Patients were for 55% and for 49% of the treatment period within a range of +/-0.5 from the therapeutic target INR during self-management and anticoagulation clinic management, respectively (p=0.06). The proportion of patients who spent most time in the therapeutic target range was larger during self-management than during anticoagulation clinic-guided management. The odds ratio for a better control of anticoagulation (defined as the period of time in the therapeutic target range) during self-management compared with anticoagulation clinic-guided management was 4.6 (95% CI 2.1-10.2). A patient-satisfaction assessment showed superiority of self-management over conventional care. INTERPRETATION Self-management of INR in the population in this study is feasible and appears to result in control of anticoagulation that is at least equivalent to management by a specialist anticoagulation clinic. It is also better appreciated by patients. Larger studies are required to assess the effect of this novel management strategy on the incidence of thromboembolic or bleeding complications.

High-dose cytosine arabinoside: pharmacological and clinical aspects

Cytosine arabinoside (Ara-C), an analogue of the nucleosides cytidine and deoxycytidine that acts as a potent inhibitor of DNA replication, was first synthesized in 1959 [1]. Since then Ara-C has become one of the most effective drugs for treatment of acute leukemia. When used as single agent in doses of 10-30 mg/m 2 complete remission (CR) can be achieved in 10-15 % of previously untreated patients with acute myelogenous leukemia (AML), whereas administration of 100200 mg/m 2 (standard-dose Ara-C) leads to complete remission in approximately 30% of the cases [2-4] . These results suggest that the success rate for Ara-C is dosage-dependent. When standard-dose Ara-C is administered in combination with anthracycline antibiotics, with or without thiopurines, the complete remission rate may increase to 6 5 7 5 % for previously untreated AML patients. Patients who do not enter CR after standard Ara-C chemotherapy are considered to have primary refractory disease. With standard combination therapy CR rates of 3 0 5 0 % can be achieved for patients with relapsed AML, which means that a substantial proportion of the 5 0 7 0 % non-responders suffers from acquired resistance to standard dose Ara-C [5]. Since Rudnicks report was published in 1979 [6] it has become clear that Ara-C resistance can be overcome by increasing the dosage. Although numerous pharmacological and clinical studies on higher Ara-C dosages have appeared, various pharmacological and clinical questions have yet to be answered. In the first part of this paper the pharmacological aspects of Ara-C action will be reviewed with special emphasis on the effect of high-dose Ara-C on resistance. The second part of the paper deals with the clinical results achieved with various high-dose Ara-C regimens.

Enhanced tumor load reduction after chemotherapy induced recruitment and synchronization in a slowly growing rat leukemia model (BNML) for human acute myelocytic leukemia.

The cell cycle perturbation effect on leukemic cells of the Brown Norway myelocytic leukemia (BNML) after high dose Ara-C injection was used as the rationale for chemotherapy studies. A one log leukemic cell load reduction as determined by means of the leukemic colony forming units-spleen (LCFU-S) assay was observed when the second Ara-C injection was administered during a period of induced accumulation of cells in S phase. evidence was obtained that Ara-C was also cytotoxic for G1 phase cells. By comparing a continuous Ara-C infusion during 24 h with two Ara-C injections at the same total dosage given 12 h apart, it was found that the tumor load was significantly more reduced in the latter group. For the drug combination Ara-C/Adriamycin, maximal LCFU-S reduction of one log was observed when Adriamycin (7.7 mg/kg) was given 12 h after Ara-C. From the increase in survival time after the schedule of 6 X Ara-C plus 1 X Adriamycin (all injections given at 12 h intervals), it could be extrapolated that the tumor load was reduced by 6.7 logs; this was in agreement with the theoretically expected reduction of 6.2 logs based on the LCFU-S experiments. The schedule of 6 X Ara-C plus 1 X Adriamycin reduced the normal haemopoietic stem cell compartment by 2.5 logs. This therapeutic gain is attributed to the specific recruitment-synchronization inducing effect of Ara-C on leukemic cells in the G0 phase.

Deoxycytidine kinase, thymidine kinase and cytidine deaminase and the formation of Ara-CTP in leukemic cells in different phases of the cell cycle

In this study we investigated the Ara-CTP-forming capacity of leukemic cells in different phases of the cell cycle. Cells from two leukemic cell lines and leukemic bone marrow cells from patients and rats (BNML model) with acute myelocytic leukemia were separated according to cell cycle phase by means of an albumin density gradient in a specially designed sedimentation chamber. We found that the activity of CdR kinase and Cyt deaminase is much less influenced by cell-cycle phase progression than TdR kinase activity. For the leukemic cell lines HL-60 and BNML-CL/O CdR kinase activity is even independent of cell-cycle phase. In addition, Ara-CTP formation is not restricted to cells in S-phase. Cell cycle phase-independent Ara-CTP formation creates a situation in which cells which are not in S-phase during exposure to Ara-C might undergo the cytotoxic effects of Ara-C as soon as they enter S-phase.

Short-term intensive treatment (V.A.A.P.) of adult acute lymphoblastic leukemia and lymphoblastic lymphoma

Increased dosages of cytosine arabinoside (Ara‐C) have been shown to be active in remission induction and consolidation treatment of patients with primary refractory acute lymphoblastic leukemia (ALL) and lymphoblastic non‐Hodgkins lymphoma (lyNHL). From August 1983 to December 1986 we treated 25 patients with ALL (9) and lyNHL, stage III and IV (16), median age 22 (range 15–48 yr) with a protocol consisting of remission induction with vincristine, prednisone, adriamycine and Ara‐C (1 g/m2 twice daily as 2‐h infusion d1–6) and intrathecal methotrexate, followed by consolidation courses with vincristine, prednisone, adriamycine and Ara‐C (3 g/m2, twice daily as 2‐h infusion d1–4) and intrathecal methotrexate. Some patients received CNS and/or mediastinal irradiation. No maintenance was given. 18 patients (72%) achieved complete remission (5 of the 11 previously treated and 13 of the 14 previously untreated patients). Consolidation courses were given to 17 patients. 5 of them relapsed in the bone marrow (3), skin (1) and CNS plus bone marrow (1) at 5, 5, 6, 6 and 24 months. The duration of complete remission ranged from 5 to 51+ months; the median could not yet be calculated. Short‐term intensive treatment might be a worthwhile approach for ALL and lyNHL.

Percentage of S-phase cells in bone marrow aspirates, biopsy specimens and bone marrow aspirates corrected for blood dilution from patients with acute leukemia

For 14 patients with acute leukemia flow cytometry was used to determine the percentage of cells in S-phase flushed out of a bone marrow biopsy compared with the percentage in a bone marrow aspirate; there was a statistically significant difference (p less than 0.01) between the two. The percentage dilution of the bone marrow aspirate by peripheral blood was then calculated, according to Holdrinet et al. [1], in order to correct the percentage S-phase cells in the aspirate. The data presented show that when the percentage S-phase cells in the aspirate is corrected for blood dilution, it closely approaches the percentage S-phase cells in the biopsy (p greater than 0.10).

Cell kinetic studies after high dose Ara-C and adriamycin treatment in a slowly growing rat leukemia model (BNML) for human acute myelocytic leukemia

The effect of high-dose cytosine arabinoside (Ara-C; 1-beta-D-arabinofuranosyl cytosine) injections (200 mg/kg i.v.) on cell cycle perturbation was investigated in a slowly growing rat leukemia (BNML) which is a realistic model for human acute myelocytic leukemia. Flow cytometric analysis showed an initial decrease of cells in S phase from 26 to 13% and a subsequent accumulation of up to 50% at 10-14 h after injection. The low number of S phase cells during the first 8 h might be due to a combination of cell kill in S phase and a block at the G1/S boundary. The results make it very likely that the origin of the accumulated S phase cells is the resting compartment and that these recruited cells enter the proliferation phase as a synchronized cell population. By repeating the Ara-C injection at the time of accumulation of cells in S phase, a similar synchronized wave of recruited cells to that after the first Ara-C injection was observed. Flow cytometric analysis after Adriamycin (7.7 mg/kg i.v.) treatment, which has been shown to be cytotoxic for BNML cells, showed no changes in cell cycle distribution. It was concluded that Adriamycin might have the same toxicity for cells in all of the different cell cycle phases. The application of these data with respect to effective tumor load reduction is discussed in a second report.

A simplified assay for measurement of cytosine arabinoside incorporation into DNA in Ara-C-sensitive and-resistant leukemic cells

SummaryThe assays for the detection of unlabeld 1-β-d-arabinofuranosylcytosine (cytosine arabinoside, Ara-C) incorporation into DNA was simplified. The procedure includes DNA isolation from leukemic cells, quantification of DNA concentrations, breakdown by enzymatic digestion of DNA to nucleosides and a radioimmunoassay (RIA) using an antibody against Ara-C. Different techniques for quantification of DNA concentrations are compared. A fluorimetric technique using Hoechst 33258 is preferred because it is the most specific method. Comparison of this RIA assay with measurement of [3H]-Ara-C/DNA formation under similar conditions in HL-60 cells showed a correlation of 0.99. Ara-C incorporation into DNA of leukemic cells was studied using two rat-leukemia cell lines, one of which is sensitive to Ara-C and the other is an Ara-C-resistant wild type: BNML-Cl/0 and BNML-Cl/Ara-C, respectively. The results showed that Ara-C is incorporated when the cells are incubated at concentrations equal to or higher than the Ara-C concentration that induces 50% growth inhibition after 48 h incubation (IC50). This implies that at lower Ara-C concentration, i. e. levels that do not induce cytotoxicity, Ara-C is not incorporated into DNA. Similar results were obtained with human HL-60 myeloid leukemia cells. The detection limit of this assay is 2 pmol/ml Ara-C; therefore, the assay is more sensitive than measurement of Ara-C triphosphate (Ara-CTP), the only metabolite that can be measured in leukemic cells from patients after in vivo Ara-C administration. On the basis of in vitro studies, the finding of detectable Ara-C/DNA levels in vivo is expected to correlate with cytotoxicity; whether or not the Ara-C/DNA level itself is informative remains to be evaluated.

Preliminary results of consolidation therapy with high-dose cytosine arabinoside for patients with bad-risk or relapsed acute leukemia or lymphoblastic non-Hodgkin's lymphoma

High-dose Ara-C consolidation therapy for patients with primary refractory or relapsed acute leukemia (AML and ALL) or relapsed lymphoblastic non-Hodgkins lymphoma (LNHL) was investigated. Between January 1983 and January 1986, 47 adult patients with primary refractory or relapsed AML, ALL or lymphoblastic NHL received a remission induction regimen that included intermediate-dose Ara-C (lg/m2/2hr q 12hr X 12). Of the twenty-nine (61.7%) patients who achieved complete remission sixteen (AML 9, ALL 5, LNHL 2) received 1-3 consolidation courses that included high-dose Ara-C (3g/m2/2hr q 12hr X 8). Three patients died as a result of major infections during the pancytopenic phase that followed the first consolidation course and 6 relapsed at 4, 4, 6, 8, 9 and 16 months; at the moment of this report the remaining 7 patients have been in continued remission for 8 to 28 months (6 have been in continued complete remission for greater than or equal to 11 months). The predicted median disease-free interval for patients who survived consolidation therapy is 16 months. Of the 13 patients who did not undergo consolidation chemotherapy 2 subsequently underwent allogeneic bone marrow transplantation and 3 died as a result of major infectious complications while in complete remission. Eight patients received no further treatment because they refused or had previously experienced severe toxicity. The median disease-free interval for this group was only 3 months. Our preliminary data on brief intensive consolidation therapy for patients with relapsed or primary refractory leukemia or non-Hodgkins lymphoma suggest that this kind of treatment prolongs disease-free interval.