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In primary care it is difficult to treat the growing number of non-insulin-dependent diabetic (NIDDM) patients according to (inter)national guidelines. A prospective, controlled cohort study was designed to assess the intermediate term (2 years) effect of structured NIDDM care in general practice with and without 'diabetes service' support on glycaemic control, cardiovascular risk factors, general well-being and treatment satisfaction. The 'diabetes service', supervised by a diabetologist, included a patient registration system, consultation facilities of a dietitian and diabetes nurse educator, and protocolized blood glucose lowering therapy advice which included home blood glucose monitoring and insulin therapy. In the study group (SG; 22 general practices), 350 known NIDDM patients over 40 years of age (206 women; mean age 65.3 +/- SD 11.9; diabetes duration 5.9 +/- 5.4 years) were followed for 2 years. The control group (CG; 6 general practices) consisted of 68 patients (28 women; age 64.6 +/- 10.3; diabetes duration 6.3 +/- 6.4 years). Mean HbA1c (reference 4.3-6.1%) fell from 7.4 to 7.0% in SG and rose from 7.4 to 7.6% in CG during follow-up (p = 0.004). The percentage of patients with poor control (HbA1c > 8.5%) shifted from 21.4 to 11.7% in SG, but from 23.5 to 27.9% in CG (p = 0.008). Good control (HbA1c < 7.0%) was achieved in 54.3% (SG; at entry 43.4%) and 44.1% (CG; at entry 54.4%) (p = 0.013). Insulin therapy was started in 29.7% (SG) and 8.8% (CG) of the patients (p = 0.000) with low risk of severe hypoglycaemia (0.019/patient year). Mean levels of total and HDL-cholesterol (SG), triglycerides (SG) and diastolic blood pressure (SG + CG) and the percentage of smokers (SG) declined significantly, but the prevalence of these risk factors remained high. General well-being (SG) did not change during intensified therapy. Treatment satisfaction (SG) tended to improve. Implementation of structured care, including education and therapeutic advice, results in sustained good glycaemic control in the majority of NIDDM patients in primary care, with low risk of hypoglycaemia. Lowering cardiovascular risk requires more than reporting results and referral to guidelines.

In this study the hypothesis that inhibition of the de novo pathway results in stimulation of salvage pathway activity was tested. The key enzyme in the balance between these two pathways is ribonucleotide reductase (RR), which can be inhibited by hydroxyurea (HU). The metabolism of 1-beta-D-arabinofuranosylcytosine and 5-Aza-2 deoxycytidine (Aza-dC), which are activated via the salvage pathway, was evaluated in cells from Ara-C-sensitive and -resistant myelocytic leukemia cell line (BNML-Cl/0 and BNML-Cl/Ara-C). The combination of HU and Ara-C caused as much as a threefold increase of Ara-CTP; it significantly increased the incorporation of Ara-C into DNA and induced synergistic cytotoxicity, as evaluated in a colony assay. Even in the deoxycytidine (CdR) kinase-deficient Ara-C-resistant cell line, HU was partially able to restore sensitivity to Ara-C and Aza-dC. dCTP levels are reduced during the first 10 h after incubation with HU, but this effect vanishes at the time when phosphorylation is maximal. Increased CdR kinase activity in cell-free extracts could explain the enhanced synthetic salvage pathway activity, which is likely due to the fact that more enzyme is present (Vmax has increased by Km unchanged). RR inhibition combined with Ara-C might provide a means of eliminating leukemic cells with suboptimal anabolic salvage pathway activity, which otherwise survive Ara-C chemotherapy.

In this study 10 patients with acute myelocytic leukemia (AML) each received a rapid intravenous injection of high dose cytosine arabinoside (HD Ara-C; 1 g/m2). Bone marrow aspirates were obtained before and after Ara-C administration to determine the percentage of cells in S-phase measured by flow cytometry. In 5 out of 10 cases synchronization of the leukemic cells in S-phase of the cell cycle was observed. However, the time of maximum synchronization turned out to be difficult to predict. Therefore, the strong correlation between percentage of cells in S-phase at diagnosis and the time of maximal accumulation of S-phase cells after Ara-C administration, as observed by others in childhood AML, could not be confirmed for adult AML patients. Although synchronization of AML cells after in vivo Ara-C administration could be demonstrated in at least half of the patients, the practical consequences are such that clinical application was hampered.

The assays for the detection of unlabeled 1-beta-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.

Seventy-two adults were treated for acute myelogenous leukaemia (AML). Forty-two had previously untreated AML and 30 had AML after a preleukaemic phase, refractory AML or relapsed AML. The previously untreated patients received a 7-day course of cytosine arabinoside (100 or 200 mg/m2 daily), daunorubicin and vincristine while the remaining patients received a 7-day course of cytosine-arabinoside (1 g/m2 q 12h for 6 days) and amsacrine (on day 7). The percentage of malignant cells and the reduction in the percentage of malignant cells were determined by means of bone marrow aspirates taken on day 6 of the chemotherapy course and at the time of diagnosis. Both variables correlated significantly with the ultimate treatment outcome; the reduction in the percentage of malignant cells correlated even more significantly than the absolute percentage malignant cells in the day-6 bone marrow. By means of multiple regression analysis it became possible to calculate the probability of achieving complete remission for the individual patient; this is given by the equation: probability = 1.9-0.009X (% malignant cell reduction). In addition, the mean percentage of malignant cells in the day-6 bone marrow was significantly higher for patients who failed to achieve than those who entered complete remission. Eighty-six per cent of the patients with less than 20% malignant cells on day 6 entered remission, while 75% of the patients with more than 21% malignant cells failed to achieve complete remission (p less than 0.001). Although all of these calculations support the predictive value of the day-6 bone marrow aspirate, the 95% confidence intervals are too large to allow reliable and safe predictions; therefore more patients must be studied to demonstrate the reliability of this test.