Basic fibroblast growth factor is cardioprotective in ischemia-reperfusion injury.

To examine whether basic fibroblast growth factor (bFGF) administered to the heart by perfusion can improve cardiac resistance to injury we employed an isolated rat heart model of ischemia-reperfusion injury and determined the extent of functional recovery in bFGF-treated and control hearts. Global ischemia was simulated by interruption of flow for 60 min. Recovery of developed force of contraction (DF), recorded after reestablishment of flow for 30 min, reached 63.

A C-terminal FMS mutation in a patient with B-cell malignancy.

The FMS proto-oncogene encodes a polypeptide growth factor receptor expressed on the cell surface of monocytes and B lymphocytes within the haematological system. Mutations of the FMS gene at codons 301 and 969 have been detected in a number of haematological disorders. Mutations at these codons are thought to be important in the pathogenesis of leukaemia in cells expressing a mutant receptor.

A novel CSF-1 binding factor in a patient in complete remission following cytotoxic therapy for lymphoma.

A novel colony stimulating factor-1 (CSF-1) binding factor present in the serum from a patient in remission from lymphoma is described. Radioimmunoassay (RIA) repeatedly failed to detect circulating levels of CSF-1 in the peripheral blood system of this patient. Molecular analysis showed a normal CSF-1 gene structure by Southern blot analysis and a 46,XX karyotype by cytogenetic analysis.

Topoisomerase II alpha expression in acute myeloid leukaemia and its relationship to clinical outcome.

The treatment of acute myeloid leukaemia (AML) is often complicated by resistance to chemotherapeutic drugs. Many of the most effective drugs used to treat haematological malignancies target the nuclear enzyme topoisomerase II. Resistance to these drugs in vitro has been associated with quantitative and qualitative changes in the enzyme.

In vitro drug resistance in acute myeloid and chronic B-lymphocytic leukaemic blasts and in normal blood and marrow populations.

The sensitivities of AML and BCLL blasts to daunorubicin have been determined, using an in vitro (MTT) assay of resistance, and compared with the sensitivities of normal haemopoietic populations and cells of the multidrug-resistant, T-lymphoid line CEM VLB100; The role of the drug-efflux pump, P-glycoprotein, was determined by adding the 'modifier' cyclosporin and by measuring numbers of P-glycoprotein positive cells by immunofluorescence. ID50s for 17 cases of de novo AML varied from 5 to 300 ng/ml giving a median of 105 ng/ml which was similar to the median of 11 normal marrow mononuclear cell preparations (80 ng/ml) but considerably less than the median ID50 of eight blood lymphocyte samples (3500 ng/ml). ID50s for five relapsed and two refractory AML samples ranged from 27 to 240 ng/ml, well within the de novo range: we had obtained presentation samples for two of these and, in both cases, ID50s were lower at relapse.

Ionic strength dependence of calcium, adenine nucleotide, magnesium, and caffeine actions on ryanodine receptors in rat brain.

[3H]Ryanodine binding studies of ryanodine receptors in brain membrane preparations typically require the presence of high salt concentrations in assay incubations to yield optimal levels of binding. Here, radioligand binding measurements on rat cerebral cortical tissues were conducted under high (1.0 M KCl) and low (200 mM KCl) salt buffer conditions to determine the effects of ionic strength on receptor binding properties as well as on modulation of ligand binding by Ca2+, Mg2+, beta, gamma-methylene-adenosine 5'-triphosphate (AMP-PCP), and caffeine.

Non-dysplastic myelodysplasia?

Patients successfully treated for a malignancy with cytotoxic therapy have an increased risk of developing secondary myelodysplasia (MDS) and acute myeloid leukemia (AML). We report a patient in remission from Hodgkin's disease (HD) who remains hematologically normal 4 years after combination chemotherapy, but who has biological and genetic abnormalities characteristic of myelodysplasia. X-inactivation analysis using a 5' phosphoglycerate kinase (PGK) probe demonstrates polyclonal hematopoiesis, but cytogenetic analysis reveals a clonal population with a minority of metaphases having a 7q-deletion.

Two new polymorphisms but no mutations of the KIT gene in patients with myelodysplasia at positions corresponding to human FMS and murine W locus mutational hot spots.

The KIT proto-oncogene encodes a tyrosine kinase receptor which plays a critical role in haemopoiesis. We have screened genomic DNA from bone marrow mononuclear cells of 46 patients with myelodysplasia (MDS) for mutations/deletions of exons 6, 13, 17, and 21 of the KIT gene (stem cell factor receptor) using polymerase chain reaction (PCR), polyacrylamide gel electrophoresis, and autoradiography to detect single-stranded conformational polymorphisms (SSCP). These exons include positions analogous to those mutated in the FMS gene (colony-stimulating factor-1 receptor) in myelodysplastic syndrome (MDS) and mutated/deleted in the Dominant White Spotting mouse (W locus) which results in macrocytic anaemia.

Topoisomerase II expression in normal haemopoietic cells and chronic lymphocytic leukaemia: drug sensitivity or resistance?

Chronic lymphocytic leukaemia (CLL) is a progressive disease, commonly treated in its early stage with alkylating agents. A multi-agent regimen which includes anthracyclines is used to treat advanced disease. Despite chemotherapy, the disease remains incurable.

Clonal haemopoiesis following cytotoxic therapy for lymphoma.

Patients successfully treated for lymphoma by conventional cytotoxic therapy are at increased risk of developing treatment-related myelodysplasia and acute myeloid leukaemia. In this study we have investigated a group of haematologically normal females in remission from lymphoma for evidence of clonal haemopoiesis as a possible marker for the development of clonal haemopoietic disorders. Unilateral X-inactivation, and hence clonality, can be determined in females heterozygous for X-linked restriction fragment length polymorphisms by differences in methylation between active and inactive X-chromosomes.

Expression of the colony-stimulating factor 1 receptor in B lymphocytes.

The FMS proto-oncogene encodes for the colony-stimulating factor 1 receptor (CSF-1R), whose expression within the haematopoietic system has previously been thought to be restricted to cells of the mononuclear phagocyte lineage. We have studied the expression of the CSF-1R in peripheral blood mononuclear cells by indirect immunofluorescence and flow cytometry. FMS expression was detected on both monocytes and B lymphocytes from all samples analysed, including 14 haematologically normal individuals and 31 patients (23 in remission following cytotoxic therapy for lymphoma, six with B-cell chronic lymphocytic leukaemia and two with chronic myelomonocytic leukaemia).

Increased basic fibroblast growth factor (bFGF) accumulation and distinct patterns of localization in isoproterenol-induced cardiomyocyte injury.

Basic FGF is a multifunctional protein which promotes regeneration in several tissues. To investigate involvement in cardiac injury-repair, bFGF accumulation and localization was examined in hearts of rats injected with a single high dose of isoproterenol. The bFGF content of cardiac extracts was analyzed at 6 and 24 hours as well as 1, 4, and 6 weeks by western blotting of heparin-sepharose-bound fractions.

Genetic lesions in preleukemia.

The incidence of genetic abnormalities have been investigated in a variety of preleukaemic states RAS and FMS oncogene, p53 suppressor gene mutations and monoclonality in myelodysplastic syndromes (MDS), a paradigm for pre-leukemias have been observed. Other patients at risk of developing either secondary leukaemia or evolving into leukaemia have been similarly studied including haematologically normal patients in remission from lymphoma. Time from treatment to detection of genetic abnormalities is a significant factor in some of these patients which is consistent with the expansion of an abnormal clone.

Depression of cardiac sarcolemmal phospholipase D activity by oxidant-induced thiol modification.

Myocardial phospholipase D (PLD) is primarily localized at the sarcolemmal level and selectively hydrolyzes phosphatidylcholine to form phosphatidic acid as part of the signal transduction mechanisms for regulating Ca2+ movements in the heart. Since the myocardial cell damage induced by oxidative stress is associated with abnormalities in Ca2+ homeostasis and thiol status, we examined the thiol group dependence and the effects of oxidant species on this enzyme. Sarcolemmal membranes isolated from rat heart were exposed to several types of thiol group modifiers.

Multidrug resistance in leukaemia.

Multidrug resistance hampers successful chemotherapy in many haematological neoplasms and is mediated by several cellular proteins. In some cases, the genes encoding these proteins have been shown to confer resistance on transfer to drug-sensitive cell lines. This is true for the efflux pump product of the MDR1 gene, P-170.

Methylation of the DXS255 hypervariable locus 5' CCGG site may be affected by factors other than X-chromosome activation status.

Differences in the methylation status of certain cytosine residues between active and inactive X chromosomes can be used to determine X-inactivation in females heterozygous for X-linked restriction fragment length polymorphisms. We have studied methylation patterns in 105 females heterozygous at the DXS255 locus by Southern blotting of PstI and MspI or HpaII double digests and hybridization with the probe M27B. Unequivocal patterns of unilateral or bilateral X-inactivation were obtained in 15/64 and 49/64 cases, respectively.

High affinity [3H]ryanodine binding sites in postmortem human brain: regional distribution and effects of calcium, magnesium and caffeine.

The pharmacological properties, regional distribution and autoradiographic localization of [3H]ryanodine binding sites were examined in postmortem human brain. Analyses of binding data from labeled ryanodine titration experiments conducted in frontal cortex revealed a single class of high affinity binding sites with a Kd value of 3.6 nM and a Bmax value of 99 fmol/mg protein.

Clonal lymphocytes are detectable in only some cases of MDS.

Clonal analysis of lymphocytes from patients with myelodysplastic syndrome (MDS) has been carried out using X-chromosome inactivation patterns detected by the probe M27 beta, and by polymerase chain reaction amplification of the immunoglobulin heavy chain gene hypervariable region, CDR3. Of 32 female patients heterozygous for M27 beta only seven (22%) demonstrate monoclonality of peripheral blood lymphocytes. 12 (37%) give unequivocal polyclonal results and the remaining cases give patterns of X-inactivation which cannot be interpreted either way.

Dek-can rearrangement in translocation (6;9)(p23;q34).

The translocation (6;9)(p23;q34) is mainly found in specific subtypes of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). The diagnosis of this translocation is not easy since the cytogenetic change is quite subtle. The two genes involved in this translocation were recently isolated and diagnosis at the DNA-level became an additional option.

Rat brain adenosine deaminase after 2'-deoxycoformycin administration: biochemical properties and evidence for reduced enzyme levels detected by 2'-[3H]deoxycoformycin ligand binding.

Near total inhibition of brain adenosine deaminase (ADA) activity in rats injected with the potent ADA inhibitor 2'-deoxycoformycin (DCF) was previously shown to reduce enzyme activity for up to 50 days during which time the enzyme exhibited reduced sensitivity to in vivo inhibition by DCF. Here, we investigated the biochemical properties of ADA and the basis for its reduced activity after DCF treatment. It was found that much higher doses of DCF were required to inhibit ADA in DCF-treated compared with drug-naive animals.