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The genomes of myeloid malignancies are characterized by epigenomic abnormalities. Heterozygous, inactivating ten-eleven translocation 2 (TET2) mutations and neomorphic isocitrate dehydrogenase (IDH) mutations are recurrent and mutually exclusive in acute myeloid leukaemia genomes. Ascorbic acid (vitamin C) has been shown to stimulate the catalytic activity of TET2 in vitro and thus we sought to explore its effect in a leukaemic model expressing IDH1R132H. Vitamin C treatment induced an IDH1R132H-dependent reduction in cell proliferation and an increase in expression of genes involved in leukocyte differentiation. Vitamin C induced differentially methylated regions that displayed a significant overlap with enhancers implicated in myeloid differentiation and were enriched in sequence elements for the haematopoietic transcription factors CEBPβ, HIF1α, RUNX1 and PU.1. Chromatin immunoprecipitation sequencing of PU.1 and RUNX1 revealed a significant loss of PU.1 and increase of RUNX1-bound DNA elements accompanied by their demethylation following vitamin C treatment. In addition, vitamin C induced an increase in H3K27ac flanking sites bound by RUNX1. On the basis of these data we propose a model of vitamin C-induced epigenetic remodelling of transcription factor-binding sites driving differentiation in a leukaemic model.

Synopsis A new low-cost computer interface has been developed for acoustic strain gauges. The interface will operate and read up to four gauges and brings the benefits of computer control and results processing to these robust gauges. All control programming uses standard BASIC commands. To complement the interface, a program has been developed which effectively turns the computer into a complete datalogger for acoustic strain gauges. Operational modes range from immediate display of strains to long-term monitoring of the gauges under clock control.

Abstract: The human fragile-X syndrome is associated with expansions of a (CGG) n triplet repeat within the FMR1 gene. Whilst normal FMR1 arrays consist of variable numbers of (CGG)7–13 blocks punctuated with single AGG triplets, unstable arrays contain longer blocks of uninterrupted (CGG) n . The degree of instability, and subsequent risk of expansion to the fragile-X mutation, is dependent upon the length of this uninterrupted repeat. Detailed analyses of normal FMR1 array structures suggest that longer uninterrupted blocks of repeat could arise either through a process of gradual slippage or a more dramatic loss of an intervening AGG triplet. Up to 15% of Japanese and Chinese individuals have FMR1 triplet arrays centred on 36 repeats in length, a modal group not found in Caucasians. As longer FMR1 arrays have been associated with high-risk fragile-X haplotypes in some populations, we investigated the nature of these larger arrays. Sequence analysis revealed that the unusual length is due to the presence of a novel (CGG)6 block within the array. Several haplotypically related arrays contain blocks of (CGG)16 or (CGG)15, consistent with the fusion of adjacent (CGG)9 and (CGG)6 blocks after loss of the intervening AGG triplet. This is compatible with inferences from the Caucasian population that AGG loss is a mechanism by which long blocks of identical repeats are generated.

The Malaise Inventory developed by Rutter and his colleagues has been widely used to measure the level of stress experienced by mothers of disabled children. The results obtained using the inventory in a survey of 362 mothers with a disabled child are assessed for internal consistency. The reliability of the malaise scale is estimated. There was no case for dropping any items from the inventory or for applying weights to the items. However, a single dimension of emotional disturbance underlying the set of malaise items did not emerge. This finding may pose problems when the Malaise Inventory is used to test empirical hypotheses about the degree of stress.

SUBSIDISED PUBLIC TRANSPORT AND THE DEMAND FOR TRAVEL, by P. B. Goodwin, J. M. Bailey, R. H. Brisbourne, M. I. Clarke, J. R. Donnison, R. E. Render and G. K. Whiteley, Gower Publishing, Aldershot, Hampshire, England, 1983, pp. 234 (£15.00)AIRPORT PLANNING AND MANAGEMENT, by David J. Smith, John D. Odegard and William Shea. Wadsworth Publishing Co., 1984. 384 pp. ($31.45)IMPROVING RAILWAY FINANCIAL PERFORMANCE, by M. E. Beesley and P. B. Kettle. Gower Publishing Co., Aldershot, 1984. 108 pp. (£15.00)INTERNATIONAL AIR TRAFFIC CONTROL, by Arnold Field. Pergamon Press, Oxford, 1985. 231 pp. (£15.00 or $25.00 U.S.)THE ECONOMICS OF RAILWAY TRACTION, by J. Majumdar. Gower, 1985. 497 pp. (£27.50)THE STRATEGY OF DISTRIBUTION MANAGEMENT, by Martin Christopher, Gower. 182 pp. (£20.45)

Summary The molecular analysis of human X-linked disease has progressed rapidly over the last few years owing to advances in power of mapping techniques. Physical DNA maps covering more than 5 million base pairs have been constructed for several chromosomal regions. Many of these regions have now also been cloned into overlapping cosmid and YAC contigs facilitating the search for disease genes. The recent identification of the mutation in the fragile X syndrome is such an example of the power of YAC technology in the characterization of human genetic disease mutations.

In this report we examine the DNA-cellulose binding and sedimentation properties of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) receptors from rat intestine and cultured human mammary cancer cells (MCF-7) extracted in nonactivating (low salt) buffers. Receptors prepared in hypotonic buffer had low DNA binding (13%) compared to receptors extracted with 0.3 M KCl (50%). Treatment of low salt receptor preparations with KCl significantly increased (approximately 3-fold) DNA-binding (activation), demonstrating that receptors can be “activated” in vitro. Activated receptors eluted from DNA-cellulose at 0.18 M KCl. Sedimentation analysis followed by DNA-cellulose binding indicated that activated receptors are approximately 3.2 S and unactivated receptors 5.5 S in size. These results suggest that dissociation of an aggregated moiety may lead to receptor activation. Treatment of unactivated receptor with RNase did not alter DNA binding or sedimentation properties of the aggregated receptor. Treatment of unactivated receptor complexes with heat did not increase DNA binding, and molybdate did not block subsequent salt activation. In summary these results suggest that 1,25(OH)2D3 receptors undergo a salt-induced activation step similar to that described for other steroid receptor systems. However, 1,25(OH)2D3 receptors differ from other steroid receptors in not exhibiting heat activation nor having salt activation blocked by molybdate.

The molecular analysis of human X-linked disease has progressed rapidly over the last few years owing to advances in power of mapping techniques. Physical DNA maps covering more than 5 million base pairs have been constructed for several chromosomal regions. Many of these regions have now also been cloned into overlapping cosmid and YAC contigs facilitating the search for disease genes. The recent identification of the mutation in the fragile X syndrome is such an example of the power of YAC technology in the characterization of human genetic disease mutations.

The normal human FMR1 gene contains a genetically stable (CGG) n trinucleotide repeat which usually carries interspersed AGG triplets. An increase in repeat number and the loss of interspersions results in array instability, predominantly expansion, leading to FMR1 gene silencing. Instability is directly related to the length of the uninterrupted (CGG) n repeat and is widely assumed to be related to an increased propensity to form G-rich secondary structures which lead to expansion through replication slippage. In order to investigate this we have cloned human FMR1 arrays with internal structures representing the normal, intermediate and unstable states. In one replicative orientation, arrays show a length-dependent instability, deletions occurring in a polar manner. With longer arrays these extend into the FMR1 5'-flanking DNA, terminating at either of two short CGG triplet arrays. The orientation-dependent instability suggests that secondary structure forms in the G-rich lagging strand template, resolution of which results in intra-array deletion. These data provide direct in vivo evidence for a G-rich lagging strand secondary structure which is believed to be involved in the process of triplet expansion in humans.

Expansion and methylation of CGG repeat sequences is associated with Fragile X syndrome in humans. We have examined the consequences of CGG repeat expansion and methylation for nucleosome assembly and positioning on the Fragile X Mental Retardation gene 1 (FMR1) gene. Short unmethylated CGG repeats are not particularly favored in terms of affinity for the histone octamer or for positioning of the reconstituted nucleosome. However, upon methylation their affinity for the histone octamer increases and a highly positioned nucleosome assembles with the repeat sequences found adjacent to the nucleosomal dyad. Expansion of these CGG repeats abolishes the preferential nucleosome assembly due to methylation. Thus, the expansion and methylation of these triplet repeats can alter the functional organization of chromatin, which may contribute to alterations in the expression of the FMR1 gene and the disease phenotype.

In this work, we examine the cellular localization and protein interactions of mouse glucocorticoid receptors that have been overexpressed in Chinese hamster ovary (CHO) cells (Hirst, M. A., Northrop, J. P., Danielsen, M., and Ringold, G. M. (1990) Mol. Endocrinol. 4, 162-170). We demonstrate that wild-type unliganded mouse glucocorticoid receptor, which is expressed in CHO cells to a level approximately 10 times that of L cells, is localized entirely to the nucleus by indirect immunofluorescence with the BuGR antireceptor monoclonal antibody. Overexpressed receptors that have either no hormone binding activity or no DNA binding activity because of point mutations also localize to the nucleus, providing genetic proof that the nuclear localization cannot reflect a steroid-mediated shift of the receptor from the cytoplasm to the nucleus and that DNA binding activity is not required for nuclear localization. Like unliganded progesterone receptors, which also associate in a loosely bound “docking” complex with the nucleus, the mouse glucocorticoid receptor overexpressed in CHO cells is associated with both hsp90 and hsp70. This is in contrast to the untransformed mouse glucocorticoid receptor in L cell cytosol, which is associated with hsp90 but not hsp70. The difference in hsp70 association between cell types could reflect overexpression of the receptor in CHO cells. However, like receptors in CHO cells selected for very high levels of overexpression, receptors in CHO cells selected for an intermediate level of receptor expression that is comparable to that of L cells are also bound to hsp70. This observation argues against an explanation of hsp70 association based purely on receptor overexpression, and we speculate that association of the unliganded glucocorticoid receptor with hsp70 might be a consequence of its nuclear localization in the CHO cells. Although there are differences between the mouse receptor in CHO cells and L cells, the nuclear localization signal of the untransformed mouse receptor reacts equivalently with the AP64 antibody against NL1 in cytosols prepared from both cell types.

Limb ischaemia induced by a sub-maximum effort tourniquet technique was used to characterize the analgesic effects of lumbar epidural morphine in volunteers. As an index of pain threshold, we measured the time to perception of pain in an upper and a lower limb before and at intervals up to six hours following epidural injections of morphine 3.5 mg and 7.0 mg, and before and after subcutaneous injections of the same doses. Subcutaneous morphine had no significant effect on the times to perception of pain in either limb. Lumbar epidural morphine did not alter upper limb times, but markedly delayed the onset of pain in the lower limbs. This lower limb analgesic effect was apparent thirty minutes after injection, peaked at about ninety minutes and was still present after six hours. Serum levels of morphine were nearly identical after subcutaneous and epidural injections of the same dose. We conclude that lumbar epidural morphine produces marked analgesia for this type of experimental pain primarily by a “regional” effect rather than as a result of systemic absorption. This regional effect develops slowly and is prolonged.

We and others have previously shown that a two-amino acid substitution in the base of the first zinc finger of the glucocorticoid receptor DNA binding domain (DBD) is sufficient to alter the receptor's target DNA from a glucocorticoid response element (GRE) to an estrogen response element (ERE). Activation of a thyroid hormone response element (TRE) has been shown to require an additional five-amino acid change in the second zinc finger of the thyroid hormone receptor (TR). Using closely related TRE and ERE sequences, we report that a receptor containing the TR DBD activates the ERE poorly, and receptors containing essential amino acids of the estrogen receptor (ER) DBD activate the TRE poorly. The ER DBD (expressed in Escherichia coli) selectively bound to a 32P-labeled ERE (32P-ERE) as a dimer and a 32P-TRE as a monomer, whereas the TR DBD bound 32P-TRE as a dimer and 32P-ERE as a monomer. When hybrid receptor DBDs were examined, we found that the five amino acids in the second zinc finger of the TR necessary for TRE activation were also essential for dimer formation on a TRE. Dimer formation of ER on an ERE was localized to the second half of the second zinc finger. These results suggest that the ability of ER and TR to functionally discriminate between an ERE and a TRE is a result of dimerization of their DBDs.

The effects of long-acting narcotic agonist preparations on the severe withdrawal syndrome following abrupt cessation of daily injections of codeine phosphate were studied in rats. Twelve hours after the last codeine injections, one injection of either a high or low dose of the zinc tannate salt of heroin, levo-alpha-acetylmethadol (LAAM) or hydromorphone in slow-release vehicle (SRV) was administered. Body weight, core temperature and hyperirritability scores (Teiger, 1974) were recorded every 6 h for the next 3 days. With the exception of the group that received the lower dose of heroin zinc tannate, all drug-treated groups lost significantly less weight than the SRV controls. All rats injected with either LAAM or hydromorphone zinc tannate exhibited prolonged marked hyperthermia, but the low, the high dose heroin groups and the SRV groups showed no significant differences in diurnal temperature patterns. Rats treated with the narcotic agonists were generally less irritable, as indicated by lower Teiger scores. These results indicate that a single injection of heroin, LAAM or hydromorphone zinc tannate can ameliorate the characteristic and intense signs of abstinence following withdrawal from codeine.

The procedure for the hierarchical aggregation of interaction data advocated by Masser and Brown (1975) does not take into account variations in the size of the row and column totals of the interaction matrix during the grouping process. The evaluation of cell entries within the matrix according to the objective function in the proposed aggregation procedure is thereby invalidated. Prior adjustment of the interaction matrix, so that both rows and columns in the resultant matrix sum to the same arbitrary total, effectively overcomes the problem of size effects.

The isoquinolines, salsolinol and 3-carboxysalsolinol, prolong ethanol-induced narcosis in mice. Pretreatment with carbidopa increases the effect of 3-carboxysalsolinol but not of salsolinol. These results suggest that ethnol sleeping-time potentiation byl-DOPA may involve a partial conversion to the isoquinoline in vivo. A central depressant action of salsolinol or the 3-carboxy analogue is suggested.

A biphasic dose-response pattern is generated by the isoquinoline, 3-carboxysalsolinol, in analgesia tests conducted in mice. Carbidopa pretreatment enhances this effect, as well as the morphine-induced analgesic increase by 3-carboxysalsolinol. Naloxone blockade of all of these responses suggests an interaction of the alcohol-based isoquinoline with central opiate receptors.

AIRLINE OPERATIONS RESEARCH by Dusan Teodorovic, pp. 466 published by Gordon and Breach (Transportation Studies Vol. 10) ISBN: 2-88124-6729THE INTERNATIONAL AIRLINE INDUSTRY: TRENDS, ISSUES AND CHALLENGES by Nawal K. Taneja, Lexington, Mass., Lexington Books, 1988. pp. 167.

THE idea that humic acids are heteropolycondensates1of phenolic substances with or without the participation of amino-acids is now widely accepted. Three possible sources of the phenols are postulated: (1) phenolic materials such as flavonoids leached from the plant debris; (2) phenolic units formed during the decomposition of lignin; (3) phenolic substances synthesized by soil micro-organisms which may have been utilizing carbohydrates. However, attempts to identify the units in the condensate have been hampered by the absence of degradative procedures, which yield monomers with unchanged substitution patterns and intact carbon side-chains. Previous chemical investigations have, therefore, been primarily concerned with elemental analysis and the determination of active groups1,2which are mainly carboxyl and phenolic hydroxyls and possibly smaller quantities of quinonoid and primary alcohol groupings.

Presents the findings of research carried out by Hilton International into its customers′ and employees′ attitudes and expectations describes the company′s subsequent actions. Looks at how employee empowerment and the creation of ′The Hilton Promise′ have lead to significant improvements in service quality. Describes ′The Hilton Club′ a database of guests′ information and preferences which allows staff to cater to guests′ needs before they even arrive.