Astrocytic expression of ZIP14 (SLC39A14) is part of the inflammatory reaction in chronic neurodegeneration with iron overload.

Neurodegeneration is associated with inflammation and mismanaged iron homeostasis, leading to increased concentration of non-transferrin-bound iron (NTBI) in the brain. NTBI can be taken up by cells expressing Zrt-, Irt-like protein-14 (ZIP14), which is regulated by iron overload and pro-inflammatory cytokines, for example, interleukin-1ß (IL-1ß) and IL-6. Here, we focus on the astrocytic involvement and regulation of ZIP14 in an experimental model of chronic neurodegeneration with inflammation and iron overload. Rats were unilaterally injected with ibotenic acid in striatum resulting in excitotoxicity-induced neuronal loss in substantia nigra pars reticulata (SNpr). ZIP14 expression was measured in SNpr using immunohistochemistry, western blotting, and RT-qPCR. Cultures of primary astrocytes were examined for Zip14 mRNA expression after stimulation with ferric ammonium citrate (FAC), IL-6, or IL-1ß. To study the involvement of ZIP14 in astrocytic iron uptake, uptake of 59 Fe was investigated after treatment with IL-1ß and siRNA-mediated ZIP14 knockdown. In the lesioned SNpr, reactive astrocytes, but not microglia, revealed increased ZIP14 expression with a main confinement to cell bodies and cellular processes. In astrocyte cultures, FAC and IL-1ß stimulation increased Zip14 expression and IL-1ß stimulation increased uptake of 59 Fe. Increased 59 Fe uptake was also observed after siRNA-mediated ZIP14 knockdown suggesting that lowering of ZIP14 impaired the balance between astrocytic uptake and export of iron. We conclude that astrocytes increase ZIP14 expression in response to inflammation and iron exposure and that ZIP14 seems pertinent for iron uptake in astrocytes and plays a role for a balanced astrocytic iron homeostasis.

Central role for melanocortin-4 receptors in offspring hypertension arising from maternal obesity.

Melanocortin-4 receptor (Mc4r)-expressing neurons in the autonomic nervous system, particularly in the paraventricular nucleus of the hypothalamus (PVH), play an essential role in blood pressure (BP) control. Mc4r-deficient (Mc4rKO) mice are severely obese but lack obesity-related hypertension; they also show a reduced pressor response to salt loading. We have previously reported that lean juvenile offspring born to diet-induced obese rats (OffOb) exhibit sympathetic-mediated hypertension, and we proposed a role for postnatally raised leptin in its etiology. Here, we test the hypothesis that neonatal hyperleptinemia due to maternal obesity induces persistent changes in the central melanocortin system, thereby contributing to offspring hypertension. Working on the OffOb paradigm in both sexes and using transgenic technology to restore Mc4r in the PVH of Mc4rKO (Mc4rPVH) mice, we have now shown that these mice develop higher BP than Mc4rKO or WT mice. We have also found that experimental hyperleptinemia induced in the neonatal period in Mc4rPVH and WT mice, but not in the Mc4rKO mice, leads to heightened BP and severe renal dysfunction. Thus, Mc4r in the PVH appears to be required for early-life programming of hypertension arising from either maternal obesity or neonatal hyperleptinemia. Early-life exposure of the PVH to maternal obesity through postnatal elevation of leptin may have long-term consequences for cardiovascular health.

Malaria Biomimetic for Tumor Targeted Drug Delivery.

Malaria infected erythrocytes utilize the parasite protein VAR2CSA to bind to a unique presentation of chondroitin sulfate (CS) for their placenta specific tropism. Interestingly, many cancers express a similar form of CS, thereby termed oncofetal CS (ofCS). The distinctive tropism of malaria infected erythrocytes and the identification of oncofetal CS, therefore, represent potentially potent tools for cancer targeting. Here we describe an intriguing drug delivery platform that effectively mimics infected erythrocytes and their specificity for ofCS. We used a lipid catcher-tag conjugation system for the functionalization of erythrocyte membrane-coated drug carriers with recombinant VAR2CSA (rVAR2). We show that these malaria mimicking erythrocyte nanoparticles (MMENPs) loaded with docetaxel (DTX) specifically target and kill melanoma cells in vitro. We further demonstrate effective targeting and therapeutic efficacy in a xenografted melanoma model. These data thus provide a proof of concept for the use of a malaria biomimetic for tumor targeted drug delivery. Given the broad presentation of ofCS found across various types of malignancies, this biomimetic may therefore show potential as a broadly targeted cancer therapy against multiple tumor indications.

Sortilin regulates blood-brain barrier integrity.

Brain homeostasis depends on the existence of the blood-brain barrier (BBB). Despite decades of research, the factors and signalling pathways for modulating and maintaining BBB integrity are not fully elucidated. Here, we characterise the expression and function of the multifunctional receptor, sortilin, in the cells of the BBB, in vivo and in vitro. We show that sortilin acts as an important regulatory protein of the BBB's tightness. In rats lacking sortilin, the BBB was leaky, which correlated well with relocated distribution of the localisation of zonula occludens-1, VE-cadherin and ß-catenin junctional proteins. Furthermore, the absence of sortilin in brain endothelial cells resulted in decreased phosphorylation of Akt signalling protein and increased the level of phospho-ERK1/2. As a putative result of MAPK/ERK pathway activity, the junctions between the brain endothelial cells were disintegrated and the integrity of the BBB became compromised. The identified barrier differences between wild-type and Sort1-/- brain endothelial cells can pave the way for a better understanding of sortilin's role in the healthy and diseased BBB.

A simple method for detecting oncofetal chondroitin sulfate glycosaminoglycans in bladder cancer urine.

Proteoglycans in bladder tumors are modified with a distinct oncofetal chondroitin sulfate (ofCS) glycosaminoglycan that is normally restricted to placental trophoblast cells. This ofCS-modification can be detected in bladder tumors by the malarial VAR2CSA protein, which in malaria pathogenesis mediates adherence of parasite-infected erythrocytes within the placenta. In bladder cancer, proteoglycans are constantly shed into the urine, and therefore have the potential to be used for detection of disease. In this study we investigated whether recombinant VAR2CSA (rVAR2) protein could be used to detect ofCS-modified proteoglycans (ofCSPGs) in the urine of bladder cancer patients as an indication of disease presence. We show that ofCSPGs in bladder cancer urine can be immobilized on cationic nitrocellulose membranes and subsequently probed for ofCS content by rVAR2 protein in a custom-made dot-blot assay. Patients with high-grade bladder tumors displayed a marked increase in urinary ofCSPGs as compared to healthy individuals. Urine ofCSPGs decreased significantly after complete tumor resection compared to matched urine collected preoperatively from patients with bladder cancer. Moreover, ofCSPGs in urine correlated with tumor size of bladder cancer patients. These findings demonstrate that rVAR2 can be utilized in a simple biochemical assay to detect cancer-specific ofCS-modifications in the urine of bladder cancer patients, which may be further developed as a noninvasive approach to detect and monitor the disease.

The vascular basement membrane in the healthy and pathological brain.

The vascular basement membrane contributes to the integrity of the blood-brain barrier (BBB), which is formed by brain capillary endothelial cells (BCECs). The BCECs receive support from pericytes embedded in the vascular basement membrane and from astrocyte endfeet. The vascular basement membrane forms a three-dimensional protein network predominantly composed of laminin, collagen IV, nidogen, and heparan sulfate proteoglycans that mutually support interactions between BCECs, pericytes, and astrocytes. Major changes in the molecular composition of the vascular basement membrane are observed in acute and chronic neuropathological settings. In the present review, we cover the significance of the vascular basement membrane in the healthy and pathological brain. In stroke, loss of BBB integrity is accompanied by upregulation of proteolytic enzymes and degradation of vascular basement membrane proteins. There is yet no causal relationship between expression or activity of matrix proteases and the degradation of vascular matrix proteins in vivo. In Alzheimer's disease, changes in the vascular basement membrane include accumulation of Aß, composite changes, and thickening. The physical properties of the vascular basement membrane carry the potential of obstructing drug delivery to the brain, e.g. thickening of the basement membrane can affect drug delivery to the brain, especially the delivery of nanoparticles.

An Oncofetal Glycosaminoglycan Modification Provides Therapeutic Access to Cisplatin-resistant Bladder Cancer.

BACKGROUND: Although cisplatin-based neoadjuvant chemotherapy (NAC) improves survival of unselected patients with muscle-invasive bladder cancer (MIBC), only a minority responds to therapy and chemoresistance remains a major challenge in this disease setting. OBJECTIVE: To investigate the clinical significance of oncofetal chondroitin sulfate (ofCS) glycosaminoglycan chains in cisplatin-resistant MIBC and to evaluate these as targets for second-line therapy. DESIGN, SETTING, AND PARTICIPANTS: An ofCS-binding recombinant VAR2CSA protein derived from the malaria parasite Plasmodium falciparum (rVAR2) was used as an in situ, in vitro, and in vivo ofCS-targeting reagent in cisplatin-resistant MIBC. The ofCS expression landscape was analyzed in two independent cohorts of matched pre- and post-NAC-treated MIBC patients. INTERVENTION: An rVAR2 protein armed with cytotoxic hemiasterlin compounds (rVAR2 drug conjugate [VDC] 886) was evaluated as a novel therapeutic strategy in a xenograft model of cisplatin-resistant MIBC. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Antineoplastic effects of targeting ofCS. RESULTS AND LIMITATIONS: In situ, ofCS was significantly overexpressed in residual tumors after NAC in two independent patient cohorts (p<0.02). Global gene-expression profiling and biochemical analysis of primary tumors and cell lines revealed syndican-1 and chondroitin sulfate proteoglycan 4 as ofCS-modified proteoglycans in MIBC. In vitro, ofCS was expressed on all MIBC cell lines tested, and VDC886 eliminated these cells in the low-nanomolar IC50 concentration range. In vivo, VDC886 effectively retarded growth of chemoresistant orthotopic bladder cancer xenografts and prolonged survival (p=0.005). The use of cisplatin only for the generation of chemoresistant xenografts are limitations of our animal model design. CONCLUSIONS: Targeting ofCS provides a promising second-line treatment strategy in cisplatin-resistant MIBC. PATIENT SUMMARY: Cisplatin-resistant bladder cancer overexpresses particular sugar chains compared with chemotherapy-naïve bladder cancer. Using a recombinant protein from the malaria parasite Plasmodium falciparum, we can target these sugar chains, and our results showed a significant antitumor effect in cisplatin-resistant bladder cancer. This novel treatment paradigm provides therapeutic access to bladder cancers not responding to cisplatin.

2-chlorodeoxyadenosine (2-CdA) in 2-hour versus 24-hour intravenous infusion in the treatment of patients with hairy cell leukemia.

Forty one patients with hairy cell leukemia (HCL) were treated with 2-chloro-deoxyadenosine (2-CdA) administered in various schedules. Complete remission (CR) was achieved in 31 (76%) patients and partial remission (PR) in 9 (22%). The mean duration of remission (CR + PR) was 25.2 months (range 9-45 months). One patient did not respond to therapy. Twelve out of 16 patients (75%) achieved CR after 5-day intravenous infusions of 2-CdA and 19 out of 25 patients (76%) after 7-day courses. In 19 out of 23 patients (82.6%) CR was achieved after intermittent 2-hour infusions and in 12 out of 18 (66.7%) after continuous 24-hour infusion. The differences were not statistically significant. Side effects of 2-CdA were similar in both groups except for infections, which were less frequently observed in the group treated for 5 days. The results of our study suggest that 2-CdA can be effectively administered to patients with HCL using 5-day courses and a 2-hour daily infusion.

Activity of 2-chlorodeoxyadenosine (Cladribine) in 2-hour intravenous infusion in 94 previously treated patients with low grade non-Hodgkin's lymphoma.

The purpose of our study was to determine the efficacy of 2-chlorodeoxyadenosine (2-CdA) administered in 2-hour intravenous infusions in previously treated patients with low grade non-Hodgkin's lymphoma (LGNHL). We treated 94 LGNHL patients with 2-CdA at a dosage of 0.12 mg/kg/24h in 2-hour intravenous infusion for 5 consecutive days. The treatment consisted of from 1 to 7 courses (median 3), repeated usually at monthly intervals. All patients were refractory to or relapsed after standard chemotherapy. Of these 94 patients 78 (83%) had clinical stage IV of the disease. Complete response (CR) was obtained in 12 (12.8%) and partial response (PR) in 36 (38.3%) giving an overall response rate of 51.1%. In 12 (12.8%) grade 4 thrombocytopenia with haemorrhagic diathesis was noted, grade 4 neutropenia was observed in 12 (12.8%) and infections complicated the course of treatment in 38 (40.4%) patients. 2-CdA treatment was the cause of death of 3 patients. The results of our study show that 2-CdA given in 2-hour infusions is an effective agent in advanced, heavily pretreated patients with LGNHL.

Intermittent 2-hour intravenous infusions of 2-chlorodeoxyadenosine in the treatment of 110 patients with refractory or previously untreated B-cell chronic lymphocytic leukemia.

The purpose of our study was to determine the effectiveness of 2-CdA in 2-hour intravenous infusions in the treatment of B-CLL. One hundred and ten patients with B-CLL received 1 to 10 courses of 2-CdA (median 2.5) at a dosage of 0.12 mg/kg daily for 5 consecutive days. Eighteen of them were untreated and 92 relapsed or became refractory to previous therapeutic modalities. Complete remission (CR) was achieved in 8 (7.3%) and partial remission (PR) in 35 patients (31.8%) giving an overall response rate of 39.1%. In 3 patients, cross-resistance to fludarabine was noticed. Toxic effects of 2-CdA were more frequently observed in previously treated patients. Hemorrhagic complications due to drug-induced thrombocytopenia were noticed in 25 (22.7%) and severe infections including sepsis in 14 (12.7%) patients.

Activity of platelet alpha-6-fucosyltransferase is inversely related to blood platelet concentration.

The activity of serum alpha-6-fucosyltransferase, a platelet derived enzyme, determined in sera of 22 normal individuals and 86 patients with various disorders was positively correlated with platelet counts. When the enzyme activity in 1 microliters serum was calculated per 1000 of platelets in blood (coefficient F/P) an inverse correlation became evident in that F/P was proportionally the higher the lower was platelet count in blood. The F/P values were in a good agreement with the results of direct assays of enzyme activities in isolated platelets. Neither granulocytes, lymphocytes nor red cells significantly contributed to serum enzyme activity though granulocytes enhanced the thrombin-induced enzyme release from platelets. In platelets separated by centrifugation in density gradients the enzyme was shown to be present in platelets of intermediate and high density but missing from the light ones. It is suggested that alpha-6-fucosyltransferase of platelets may be a marker of the ploidy level of megakaryocytes.

Contents of total and protein-bound carbohydrates are low in leukemic leukocytes from patients with acute myelogenous leukemia.

Leukemic leukocytes from 12 patients with acute myelogenous leukemia (AML) and two patients with chronic myelogenous leukemia (CML) were isolated by centrifugations in Percoll gradients, and examined for total carbohydrates. In leukemic leukocytes from 10 of these patients ceramide-bound carbohydrates were also determined. Protein-bound carbohydrates were calculated by subtraction of ceramide-bound carbohydrates from total carbohydrates. In all samples analysed the contents of total and protein-bound carbohydrates were much lower in leukemic leukocytes than in normal neutrophils, irrespective whether the results were expressed relative to protein, DNA, cell number or dry mass. For immature leukemic cells of M0-M1 phenotype differences up to 10-fold were observed. Contents of ceramide-bound carbohydrates, i.e. those of neutral and acidic glycosphingolipids (GSLs) were also low in leukemic cells. However, when GSL carbohydrates were calculated as percentage of total carbohydrates, GSLs in leukemic leukocytes were elevated in half of the AML patients but depressed in the other half. The results are discussed in the light of the hypothesis on GSL function by one of us (Koscielak J., 1986, Glycoconjugate J. 3, 95-108). According to one element of the hypothesis, during cell differentiation newly synthesized glycoproteins (GPs) that perform specific functions are added to house-keeping GPs that are present in plasma membranes of all types of cells. Thus, during differentiation, the GP content of the cell membrane should increase and that of the so called "membrane packing" glycosphingolipids should decrease.

The treatment of acute myeloid leukemia with mitoxantrone, etoposide and low-dose cytarabine in elderly patients - a report of Polish Acute Leukemia Group (PALG) phase II study.

The common dilemma in the treatment of elderly patients with acute myeloid leukemia (AML) is whether to use intensive myelosuppresive therapy with higher risk of treatment related mortality (TRM), but a chance for complete remission (CR), or to treat less intensively in order to prolong survival time with a better quality of life. The aim of this prospective, phase II study was to assess the efficacy and toxicity of low dose combination induction treatment consisted of cytarabine at a dose of 10 mg/m2 every 12 h s.c. for 7 days, VP-16 at a dose of 100 mg/day p.o. for 7 days and mitoxantrone at a dose of 6 mg/m2 i.v daily on days 1-3. Two induction courses were planned. In the group of 44 patients 12 (27%) achieved CR, 4 (9%) patients were in PR and there were 9 (20%) early deaths (ED). Age, performance status, preceding myelodysplastic syndrome, karyotype, WBC and % of blasts in bone marrow were not significant prognostic factors for CR probability. The following initial factors appeared to be related to a shorter duration of survival time from the start of treatment: age >70 (p<0.03), poor performance status (p<0.03), and % of BM blasts 50 (p<0.05). We conclude that, despite promising results in the pilot study the efficacy of this induction treatment is not better than the efficacy of other regimens. The hematological toxicity of this treatment seems to be comparable with "3+7" regimen.

The incidence of metamizole sodium-induced agranulocytosis in Poland.

Metamizole sodium continues to be used extensively as an analgesic in Poland. This study was the first undertaken to quantify the incidence of agranulocytosis associated with metamizole sodium in Poland, and to compare the findings with those from other countries. Based on data obtained retrospectively from medical records covering the period 1997-2001 in six haematology centres representative of Poland as a whole, the crude estimate obtained was a rate of 0.2 cases per million person-days of use. This is the same order of magnitude as the value from an epidemiological study covering several countries (0.3-4.0).

Is the internet an integral part of general practice in Australia?

Computerisation has seen significant changes in information management and procedures in General Practice. Whilst the majority of changes to date, have been apparent in administration, the clinical aspect of primary care is now increasingly taking advantage of the computer and significantly, the Internet. The professional obligation to maintain currency in medical developments has provided an opportunity to use the Internet as a low cost method to access a wide range of medical research information worldwide. Furthermore traditional methods of communication within the medical community have the potential to be transformed by the availability and use of electronic communication techniques such as email. The incorporation of these new technologies in clinical practice is not without its challenges, and includes quality, timeliness, information management and attitudes to Internet based information. This paper presents the results of a preliminary study of GP's undertaken in Western Australia analysing the usage of, and attitude to, the Internet in clinical practice.

Effect of pamidronate on skeletal morbidity in myelomatosis. Part 1. The results of the first 12 months of pamidronate therapy.

BACKGROUND: Osteolytic bone destruction caused by increase of osteolytic activity is a major manifestation of multiple myeloma (MM). Pamidronate (3-amino-1-hydroxypropylidene)-1,1-bisphosphonate) inhibits osteoclastic activity and reduces bone resorption. METHODS: Since October 1995 the efficacy of pamidronate is evaluated in MM patients all receiving anti-myeloma chemotherapy acc. to VMCP/VBAP alternating regimen. 46 patients with stage III myeloma and osteolytic lesions were randomized to receive either pamidronate (Aredia; Novartis) 60 mg i.v. in 4-hour infusion monthly (n = 23) or chemotherapy alone (control group n = 23). Estimation of performance status, quality of life, pain score, analgesic consumption, serum calcium concentration and twenty four-hours Calcium excretion, urine Calcium/creatinine ratio is done at least once a month (before pamidronate administration) while X-ray skeletal survey--before treatment and then every six months. RESULTS: In the first months of treatment apparent reduction of bone pain occurred. Hypercalcaemia was revealed in 6 patients at entry into the study. In 5 of these patients pamidronate restored and maintained normocalcaemia for a median 6 months. In 3 patients an aggressive plasma cell proliferation was accompanied by reoccurrence of hypercalcaemia. At skeletal X-ray examination performed after 6 and 12 cycles of pamidronate and by comparing each of consecutive imaging with previous one the progression of osteolysis was respectively found in 67% and 39% of patients. In the control group corresponding figures were: 79% and 70%. The mean number of skeletal events (pathologic fracture, radiation to bone and spinal cord compression) per year was lower in the pamidronate group (1.82) than in control-patients (2.72), p < 0.013. The proportion of patients who developed skeletal event (excluding vertebral fractures) was lower in the pamidronate group -34% v 52%. Adverse events of pamidronate: hypocalcaemia (< 2 mmol/l) observed in 7 patients occurred in particular patients beginning from 2 to 7 days after drug administration. In 2 patients hypocalcaemia that appeared in 24 hours after drug infusion was accompanied by blood pressure decrease; in one case systolic blood pressure dropped up to 60 mmHg, in the other one--to 90 mmHg. Muscular pain and fever up to 39 degrees C (transient and self-limiting "influenza like syndrom") occurred in 5 patients, in two patients after several hours and in three other--after some dozens of hours from drug administration. In one case hypertransaminasaemia was observed. CONCLUSIONS: In the first year of treatment monthly intravenous pamidronate administration as an adjunct to chemotherapy in patients with advanced multiple myeloma with osteolysis is an efficient approach in prevention and treatment of hyperacalcaemia, hypercalciuria and bone pain. It also shows some preventive effect on bone lesion occurrence.

[The usefulness of MRI of the central nervous system in certain diseases of blood and hemopoietic system with neurological symptoms]. / Przydatnosc badan MR osrodkowego ukladu nerwowego w niektórych chorobach krwi i ukladu krwiotwórczego przebiegajacych z symptomatologia neurologiczna.

The results are presented of MRI studies of the brain and spinal cord in patients with neurological symptoms in the course of certain diseases of the haemopoietic system (leukaemias, lymphomas). The analysis showed that MR images, although not specific, can be very useful for the evaluation of the intensity and topography of haematological lesions in the central nervous system. However, the diagnosis of these processes is not easy. In the differential diagnosis focal lesions of vasogenic origin, infections and radiation-induced lesions should be considered, and in cases of lymphoma--metastases are a possibility.

[Autoimmune thrombocytopenia in pregnant women: diagnosis, treatment and prevention of complications in children]. / Autoimmunologiczna maloplytkowosc u kobiet w ciazy: rozpoznawanie, leczenie, zapobieganie powiklaniom u dzieci.

9 pregnancies (in 6 women) complicated by autoimmune thrombocytopenia were studied. Corticosteroids and/or azathioprine and/or intravenous immunoglobulins (IgG i.v.) were administered to 5 women during pregnancy. 1 complete remission (CR) was achieved after 3 mo. of treatment by corticosteroids and azathioprine. In peripartum period the treatment was administered in 7 cases (corticosteroids, IgG i.v., platelet transfusion). There were no haemorrhagic complications during peripartum period (8 vaginal delivery, 1 cesarean section). In 3 of 5 examined cases IgG antiplatelet antibody was detected. Study group was to small to define the correlation between level of antiplatelet antibodies and neonatal thrombocytopenia. 10 infants were born. 4 infants (including siblings) were found to have normal platelet counts immediately after delivery. They mothers were treated by IgG i.v. in 2 cases and 1 women in CR at the time of delivery. 4 infants were thrombocytopenic but required no treatment. Duration time of thrombocytopenia was 1 to 4 weeks. In these cases mothers were treated only by corticosteroids or had no therapy.

[Preliminary treatment results of relapsed or refractory acute leukemia using two and three drug regimens]. / Wstepne wyniki leczenia ostrych bialaczek opornych i nawrotowych przy zastosowaniu schematów dwu--oraz trzylekowych.

36 patients with relapsed (29) or refractory (7) acute lymphoblastic or nonlymphoblastic leukaemia received regimens employing 1-3 courses of mitoxantrone (or idarubicin), intermediate doses of cytarabine and etoposide. Complete remission (CR) was achieved in 30% of patients (5/15 ALL, 6/21 AML, 5 cases of refractory and 6 of relapsed leukaemia). Duration of CR was 3-6+ months (3 patients are still alive). Toxicity of the treatment was acceptable, however 5 patients with severe granulocytopenia died from sepsis.

[Effect of hydroxyurea treatment on free nucleotides in leukemic leukocytes]. / Wplyw leczenia hydroksymocznikiem na zachowanie sie wolnych nukleotydow leukoxytów bialaczkowych

An increase was observed in the pool of free nucleotides of leukaemic leucocytes during treatment with hydroxyurea, which was used as a drug inducing remission in chronic myeloid leukaemia and as an agent synchronizing the cell cycle in the so-called synchronization treatment of acute myeloid leukaemia. The increase in the amount of free nucleotides may depend on their increased synthesis and on their less extensive utilization for synthesis of nucleic acids. According to the authors the observed changes in the pool of free nucloetides may possess certain therapeutic implications.