Autoimmune pancytopenia following combination chemotherapy for chronic lymphocytic leukaemia.

Autoimmune haemolysis or thrombocytopenia can complicate purine nucleoside monotherapy for chronic lymphocytic leukaemia (CLL), but Evans syndrome is rare. This is a report of the occurrence of pancytopenia secondary to a unique combination of red cell aplasia with autoimmune thrombocytopenia and neutropenia in a patient with CLL following treatment with fludarabine and cyclophosphamide. This case is unusual for the simultaneous targeting of three haemopoietic lineages by immune dysfunction following fludarabine and cyclophosphamide, which is a treatment regimen believed to reduce autoimmune haematological toxicity in CLL.

Role of alpha interferon in multiple myeloma.

Interferons are soluble proteins produced by cells in response to viruses. Although they were first introduced as therapeutic agents for myeloma in 1979 their exact role in the management of myeloma remains to be precisely defined. Interferons have both anti-proliferative and immune regulation effects, but the predominant mode of action of interferons in myeloma is still unclear. Recombinant alpha interferon has been used in clinical trials as a single induction agent, co-induction agents with combination chemotherapy, as salvage therapy, and as therapy to maintain plateau phase after conventional chemotherapy or complete remission after auto or allogeneic transplantation. Interferon as a single induction or co-induction agent with other forms of chemotherapy appears to be of only minimal benefit in myeloma. However, its role as maintenance agent has received a great deal of interest and investigation. Its most beneficial role would appear to be in those patients who have had good responses to either conventional therapy or to bone marrow transplantation and the beneficial role of interferon in the maintenance of plateau phase is gaining credence. Its maximum advantage appears to be in patients with initial good response who have obtained plateau phase, or in patients who have developed complete remission after auto transplantation. It also has a role as salvage treatment in refractory patients with myeloma where the combination of interferon and dexamethazone may be a useful therapeutic modality.

The myelodysplastic syndromes: an analysis of prognostic factors in 226 cases from a single institution.

Two hundred and twenty-six patients were diagnosed with myelodysplastic syndrome (MDS), according to the French-American-British (FAB) criteria, over a 13-year period, and studied retrospectively in a single institution in order to study indicators which were prognostically significant. Analysis of clinical and laboratory data indicated that the FAB classification, the Bournemouth, Dusseldorf, Goasguen, Sanz and FAB Scoring Systems were all good predictors of survival. We found advancing age, haemoglobin (Hb) < or = 9 g/dl, platelet count < or = 50 x 10(9)/l, increased peripheral total white cell count (WCC) and monocytosis, increased bone marrow blasts, dysgranulopoiesis, and bone marrow fibrosis were significant adverse prognostic variables. The commonest complication and cause of death was infection; however, infective episodes were not significantly associated with low neutrophil counts (either < or = 1.5 x 10(9)/l or < or = 0.8 x 10(9)/l) and there was also no significant association between neutropenia and survival. These findings indicate that neutrophil dysfunction plays an important role in the clinical progression of patients with MDS. The effect of new therapeutic modalities, such as the haemopoietic growth factors, on reducing infective episodes may be as significant as their effect on increasing neutrophil counts.

The interrelationships of the inositol phosphates formed in vasopressin-stimulated WRK-1 rat mammary tumour cells.

1. Temporal changes in the levels of many inositol phosphates, whose structural characterization is presented in the preceding paper [Wong, Barker, Morris, Craxton, Kirk & Michell (1991) Biochem. J. 286, 459-468], have been monitored in vasopressin-stimulated WRK-1 cells. 2. Upon stimulation, Ins(1,4,5)P3 accumulated within 1 s, consistent with its role as a rapidly acting second messenger produced by receptor activation of phosphoinositidase C. Ins(1,4)P2 and Ins(1,3,4,5)P4, both of which are immediate products of Ins(1,4,5)P3 metabolism, also accumulated quickly. Ins4P, Ins(1,3,4)P3, Ins(3,4)P2, Ins(1,3)P2, Ins1P and Ins3P, which are intermediates in the metabolism of Ins(1,4)P2 and Ins(1,3,4,5)P4 to inositol, accumulated after seconds or within a few minutes, and in a temporal sequence consistent with their known metabolic interrelationships. 3. The stimulated accumulation of Ins(1,3,4,6)P4 was delayed, as expected if it is formed by phosphorylation of Ins(1,3,4)P3. 4. Ins(3,4,5,6)P4 accumulated 2-3-fold in a few minutes, and mainly before Ins(1,3,4,6)P4. 5. Using a [3H]-/[14C]-inositol double-labelling protocol, we obtained evidence that all of the compounds that accumulated upon stimulation, except Ins(3,4,5,6)P4, originated from lipid-derived Ins(1,4,5)P3, but that the newly formed Ins(3,4,5,6)P4 came from a different source. 6. There were no consistent changes in the levels of Ins(1,3,4,5,6)P5 and InsP6 during stimulation. 7. Alongside the gradual accumulation of Ins(1:2-cyclic,4,5)P3 during stimulation [Wong, Barker, Shears, Kirk & Michell (1988) Biochem. J. 252, 1-5], there was an accumulation of Ins(1:2-cyclic,4)P2 and Ins(1:2-cyclic)P, probably as either minor side products of phosphoinositidase C action or metabolites of Ins(1:2-cyclic,4,5)P3. 8. When Li+ was present during stimulation, it redirected the dephosphorylation pathways downstream of Ins(1,4,5)P3 in the manner expected from its inhibition of inositol monophosphatase and Ins(1,4)P2/Ins(1,3,4)P3 1-phosphatase: there were marked increases in the accumulation of Ins(1,4)P2 and Ins(1,3,4)P3 and of monophosphates. Moreover, Li+ shifted the Ins1P/Ins3P balance in favour of Ins1P, thus demonstrating redirection of the metabolism of the accumulated Ins(1,3,4)P3 towards Ins(1,3)P2 rather than Ins(3,4)P2.

Inositol phosphates in receptor-mediated cell signaling: metabolic origins and interrelationships.

We have investigated the metabolic interrelationships of the major inositol phosphates in vasopressin-stimulated WRK 1 mammary tumor cells which were labeled to equilibrium with [14C]inositol and briefly, just prior to stimulation, with [3H]inositol. A comparison of the 3H/14C ratios of these compounds with those of the cellular inositol lipids suggests that most of the known inositol mono-, bis-, tris-, and tetrakis-phosphates are derived from precursors with turnover rates similar to those of these lipids. However, Ins(3,4,5,6)P4 (which is the major inositol tetrakisphosphate to accumulate in stimulated WRK 1 cells), Ins(1,3,4,5,6)P5, and InsP6 had 3H/14C ratios of 0 in this experiment, indicating that they must have a different metabolic origin.

The use of cells doubly labelled with [14C]inositol and [3H]inositol to search for a hormone-sensitive inositol lipid pool with atypically rapid metabolic turnover.

Some, though not all, previous studies have suggested that the inositol lipid which is hydrolysed during transmembrane signalling in response to receptor activation might be drawn from a metabolically discrete and relatively small hormone-sensitive lipid pool that turns over more rapidly than the bulk of membrane inositol lipid. In order to seek evidence for the existence of this putative hormone-sensitive lipid pool, we have double-labelled cells by growing them for 3 days in a medium containing [14C]inositol and then supplying them with [3H]inositol for the final 2 h before stimulation. We anticipated that stimulation of these doubly labelled cells might provoke the formation, from the postulated hormone-sensitive pool, of small quantities of relatively 3H-enriched inositol phosphates, and that these could be harvested from cells (provided that the cytosolic inositol monophosphatase and inositol 1,4-bisphosphate/inositol 1,3,4-trisphosphate 1-phosphatase activities are first inhibited by Li+). Experiments of this type, using both vasopressin-stimulated WRK1 rat mammary tumour cells and 3T3 mouse fibroblasts stimulated by prostaglandin F2 alpha, have largely failed to demonstrate the formation of relatively 3H-enriched inositol phosphates. There was a tendency for phosphatidyl-inositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate to have slightly higher 3H: 14C ratios than phosphatidylinositol, but the 3H: 14C ratios of the inositol phosphates formed in stimulated cells were not substantially greater than the 3H: 14C ratios of the inositol lipids. We therefore conclude, at least for the two cell lines that we studied, that hormone-stimulated inositol lipid hydrolysis can call, either directly or indirectly, upon the majority of the inositol lipid complement of the stimulated cell.

Inositol lipids: receptor-stimulated hydrolysis and cellular lipid pools.

Our current knowledge of the process by which receptors stimulate the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) has its origin in the discovery by Hokin & Hokin (J. biol. Chem. 263, 967 (1953] that some pancreatic secretagogues not only elicit exocrine secretion but also stimulate the metabolism of membrane phospholipids. Despite the recent elucidation of many aspects of this widespread signalling system, there is still little information on the control of the supply of its substrate, PtdIns(4,5)P2. In particular, some studies have suggested that inositol-lipid-mediated signalling involves much or all of the inositol lipid complement of the stimulated cells, whereas other observations have equally clearly implicated the receptor-activated hydrolysis of an inositol phospholipid pool that comprises only a small fraction of the total cellular complement of these lipids. These studies, which have largely employed radiochemical analyses using single isotopes, are briefly reviewed. In addition, we report the first information obtained by a new procedure for analysing the metabolic characteristics of the inositol lipids that are broken down during stimulation. This technique employs cells that are doubly labelled in the inositol moiety of their lipids (to isotopic equilibrium with 14C and only briefly with 3H) to search for functional metabolic heterogeneity among the inositol lipids of stimulated cells. Using this method, we have found that the inositol phosphates liberated in stimulated cells during brief stimulation of V1a-vasopressin receptors or prostaglandin F2 alpha receptors come from phospholipid that has a turnover rate typical of the bulk of the cellular inositol lipids.

Variability on serial testing of pattern reversal visual evoked potential latencies from full-field, half-field and foveal stimulation in control subjects.

The change in pattern reversal visual evoked potential (PRVEP) latency over time (test-retest variability, TRV) was assessed in 30 (16 males, 14 females) adult control subjects using full-field (FF), half-field (HF) and foveal (central-field, CF) stimulation. The mean test-retest interval (TRI) was 20.5 months with a range of 18-21.5 months. There were no significant test-retest latency differences in either sex and furthermore there were no significant inter-sex differences in any of the test-retest parameters. Because of the latter finding the test-retest upper limit of normal for each parameter as defined by the mean value + 2.5 S.D. was taken as the largest value obtained in either sex. Thus the test-retest upper limits of normal for absolute latency from FF, right HF, left HF and CF stimulation were 6, 7, 9 and 7 msec, respectively; for interocular latency differences (ILD) from FF and CF stimulation were 4 and 5 msec respectively; and for right HF to left HF intraocular latency difference (IOLD) was 7 msec. It is concluded that the TRV was sufficiently small in our control group with each of the stimulus techniques to make all of them potentially useful in serial PRVEP studies. Furthermore the extra information provided by CF and HF stimulation may increase the sensitivity and accuracy with which change can be monitored.