Regulation of the Wilms' tumour suppressor (WT1) gene by an antisense RNA: a link with genomic imprinting?

Antisense transcripts are typically associated with the down-regulation of gene expression. In this issue, Moorwood et al. present evidence that an antisense RNA can enhance expression of the Wilms' tumour suppressor locus WT1. We suggest that the unusual function of the WT1 antisense RNA might relate to the recent discovery of an antisense transcript that is involved in regulating imprinted expression of the murine Igf2r gene, particularly since there is some evidence that the WT1 gene is regulated by genomic imprinting in humans.

New directions in perioperative management for pediatric solid organ transplantation

Advances in pediatric solid organ transplantation have furthered the understanding of end-organ failures and refined the strategies for perioperative management of these otherwise lethal diseases. As the donor pool expands, the number of transplantations increases and long-term survival continues to improve, more complete knowledge of the immunologic and pathologic processes will be gained. A thorough understanding of the principles of transplantation medicine remains essential for physicians to provide optimal perioperative care of pediatric organ transplant patients.

Neuroendocrine, appetitive and behavioural responses to d-fenfluramine in women recovered from anorexia nervosa

BACKGROUND

Increased central serotonin (5-HT) function has been hypothesised to be a vulnerability trait in anorexia nervosa.

METHODS

Eighteen women with a history of DSM-III-R anorexia nervosa and 18 female controls were examined. The subjects had recovered weight and menstrual function. A placebo-controlled d-fenfluramine test was used. Subjects ingested d-fenfluramine or placebo and after three hours were offered a 'free' meal. The amounts eaten were recorded and plasma cortisol and prolactin levels were measured. Questionnaires related to eating attitudes and behaviour, to personality, and to mood were administered.

RESULTS

Unlike the control subjects, those recovered from anorexia nervosa did not show the expected appetite-suppressing responses to d-fenfluramine; their eating attitudes and behaviour were more restrained, 'negative' perfectionism was more pronounced, and post-meal plasma cortisol levels did not rise as expected.

CONCLUSIONS

Our results do not suggest that increased central 5-HT function is a trait marker in anorexia nervosa, but dysregulation in part of the central 5-HT system may be a vulnerability factor. The flattened post-meal response to cortisol in the subjects who had recovered from anorexia nervosa suggests that their hypothalamic pituitary--adrenal axis may be altered and deserves further investigation.

Are altered pharmacokinetics of non-steroidal anti-inflammatory drugs (NSAIDs) a risk factor for gastrointestinal bleeding?

AIMS

We hypothesised that pharmacokinetic factors might go some way to explaining the risk of major gastrointestinal haemorrhage with non-steroidal anti-inflammatory drugs (NSAIDs), with bleeders exhibiting a reduced clearance of NSAIDs compared with non-bleeders and set out to investigate this.

METHODS

Fifty patients presenting to hospital with acute gastrointestinal bleeding while taking piroxicam, indomethacin, diclofenac or naproxen and age, sex, musculoskeletal disease and drug matched community dwelling controls, up to two for each index case, who had not bled were recruited. Clinical details including duration of therapy were recorded. Bleeders discontinued the implicated NSAID at presentation, controls at least five half-lives before the study. Bleeders were contacted by letter 1 month after discharge and invited to take part and were studied after a median delay of 5 months. Subjects received an oral dose of their respective NSAID and venous blood was sampled, over a period determined by the half-life of the NSAID. Plasma concentrations were determined by high performance liquid chromatography.

RESULTS

The median length of treatment for the index patients was 1 year (range 2 weeks--28 years) and for the control patients 2 years (1 month--25 years), P<0.0005. There were no significant differences in peak plasma concentration, time to peak plasma concentration or area under the plasma concentration-time curve between bleeders or controls for any of the NSAIDs studied, apart from piroxicam Cmax being lower in bleeders at 2.07 mg l(-1) than in controls at 3.21 mg l(-1), mean difference (95% CI) -1.14 (-1.83 - -0.48), P<0.005.

CONCLUSIONS

The data failed to support the hypothesis that reduced clearance of NSAIDs, which results in higher plasma concentrations, is a risk factor for acute gastrointestinal haemorrhage.

Human growth-differentiation factor 3 (hGDF3): developmental regulation in human teratocarcinoma cell lines and expression in primary testicular germ cell tumours

We describe the cloning and initial characterization of a novel cDNA from human embryonal carcinoma (EC) cells. This cDNA, which we named human growth differentiation factor 3 (hGDF3), encodes the homologue of mouse GDF3, a TGFbeta superfamily member belonging to the Growth/Differentiation Factors. We have analysed the expression of hGDF3 in human embryonal carcinoma cell lines and in primary testicular germ cell tumours of adolescents and adults (TGCTs). Expression of hGDF3 in human EC cell lines is stem cell-specific, is down-regulated upon RA-mediated differentiation and is increased upon culture of the cells in the presence of activin A. In TGCTs, hGDF3 expression is low in seminomas, while expression in non-seminomas is readily detectable and appears to be associated with the EC and yolk sac components in the tumours. We have also mapped the hGDF3 locus to the short arm of human chromosome 12, a region consistently overrepresented in human testicular germ cell tumours. Thus, hGDF3 represents an embryonal carcinoma stem cell-associated marker both in vitro and in vivo.

Wilms' tumour-suppressor protein isoforms have opposite effects on Igf2 expression in primary embryonic cells, independently of p53 genotype

The p53 protein has been proposed as a modulator of the Wilms' tumour-suppressor protein (WT1) transcriptional regulation activity. To investigate this putative p53 role, the promoter P3 of the mouse insulin-like growth factor II gene (Igf2) was used as a target for WT1 regulation in primary cell cultures derived from p53 wild-type (p53+/+) and knock-out (p53-/-) mouse embryos. In these cells, the WT1 transcriptional activity was observed to be independent of p53 genotype. Furthermore, the two WT1 zinc finger (ZF) isoforms were for the first time found to have opposite effects on gene expression from a single promoter in the same cell type, WT1[-KTS] activating Igf2 P3, whereas WT1[+KTS] repressed its activity. In addition, we have mapped the WT1 binding sites and investigated the effect on WT1 binding activity of individual ZF deletions and Denys-Drash syndrome point mutations to this target.

Regulation of a promoter from the mouse insulin like growth factor II gene by glucocorticoids

We have microinjected constructs containing the murine IG II P3 promoter linked to different flanking sequences and a luciferase reporter gene into mouse pronuclei to establish transgenic lines of mice. The offspring was used as a source of embryonic fibroblast cultures and the effect of exogenous addition of glucocorticoids on transgene expression was analysed. It was found that both dexamethasone and hydrocortisone gave rise to a functional stimulation of the IGF II P3 promoter when the construct also contained other elements. This study demonstrates for the first time that there is an effect of glucocorticoids on the activation of an embryonic IGF II promoter, thus providing a molecular rationale for previous findings that glucocorticoids can under certain circumstances give rise to an increased transcriptional activity of the IGF II gene.

Decreased skin sensory innervation in transgenic mice overexpressing insulin-like growth factor-II

Cutaneous sensory innervation was studied in transgenic mice overexpressing insulin-like growth factor II using a keratin promoter. The skin area of these animals is enlarged providing increased target for sensory neurons. L4 dorsal root ganglion cell counts revealed that the total number of sensory neurons was the same in transgenics as control animals. Levels of nerve growth factor per unit weight of skin were also unchanged. The cutaneous nerves of the hindlimb were immunostained with the pan-neuronal marker PGP 9.5 in transgenic and control mice at postnatal day 0 and 21. The innervation in transgenic mice was markedly reduced, particularly in superficial dermis and epidermis and in some areas innervation was completely absent. The effect was greatest in distal skin regions and increased with age. Since insulin-like growth factor II has been reported to be a sensory neurotrophic factor, its effect on neurite outgrowth was tested on embryonic day 14 and 18 mouse lumbar dorsal root ganglion explants in culture. Under these conditions insulin-like growth factor II (5-100 ng/ml) did not have strong growth promoting activity and at embryonic day 18, in the presence of 5-10 ng/ml nerve growth factor, neurite outgrowth was suppressed by insulin-like growth factor II. The results show that increased skin target and availability of nerve growth factor per se do not alter the number of innervating sensory neurons. However, reduced sensory terminal arborization and skin hypoinnervation does occur in the presence of excess insulin-like growth factor-II. It is possible that insulin-like growth factor-II inhibits terminal axon growth directly via receptors on sensory neurons or peripheral glia.

Persistent osteopenia after recovery from anorexia nervosa

OBJECTIVE

Osteopenia is a known complication of anorexia nervosa. Most studies have focused on the features of the illness which predict bone complications. The few reports on recovery have been conflicting, with some studies suggesting restoration of normal bone mass with recovery from anorexia nervosa, while others suggest that the improvement may only be partial. This is the first report of bone density in a long-term recovered group.

METHOD

We measured bone density in the hip and lumbar spine in 18 recovered women, using dual energy X-ray absorptiometry.

RESULTS

We found an unexpectedly high incidence of osteopenia, with 14 of 18 women affected. Duration of amenorrhea was the best predictor of reduced bone density. An index of the duration of recovery, relating it to the duration of illness, was also highly correlated with outcome.

DISCUSSION

Our findings have implications, both for the individual and for the economic burden to society. We suggest that the use of oral contraceptives in women recovering from anorexia nervosa needs further investigation. Additional longitudinal studies are clearly warranted.

Structural investigation of resin glycosides from Ipomoea lonchophylla

A fraction from Ipomoea lonchophylla, which was toxic to mice, contained an inseparable mixture of resin glycosides with differing numbers of C5 ester groups on the hexasaccharide chain. After alkaline hydrolysis of the esters, the structure of the major component (1) was elucidated using high-field NMR spectroscopy, mass spectrometry, chemical studies, and comparison with known resin glycosides. Compound 1 was identified as 3,11-dihydroxytetradecanoic acid 11-O-beta-quinovopyranosyl-(1-->2)-beta-glucopyranosyl-(1-->3)- [alpha-rhamnopyranosyl- (1-->4)]-quinovopyranosyl-(1-->2)-beta-glucopyranosyl-(1-->2)-beta -fucopyranoside.

Disposition of intravenous 123iodopentamidine in man

This study compared the disposition of the radiopharmaceutical [123I]iodopentamidine with that of pentamidine after intravenous infusion by measuring plasma concentrations of each using scintilation counting and high-performance liquid chromatography (HPLC), respectively. There was rapid hepatic uptake and biliary excretion of the 123I label. Distribution kinetics of the 123I label were similar to those of pentamidine, but its elimination half-life (41 +/- 27 h) was longer than that of pentamidine measured by HPLC (11 +/- 8 h). [123I]iodopentamidine distribution reflects that of pentamidine, but elimination of the radiopharmaceutical appears slower.

T lymphocyte subpopulations in anorexia nervosa and refeeding

Several studies have addressed the question of the effects of starvation on immune function and changes in lymphocyte subsets. Patients with anorexia nervosa are severely malnourished, but there have been few studies of immune parameters in this group. For this reason, phenotypic markers of T cell function and activation were studied in 20 severely underweight patients with anorexia nervosa and again after a period of refeeding. The most significant finding was a reduction in the percentage and absolute number of CD8+ T cells in patients with anorexia, the result of a marked reduction in memory (CD45RO+RA-) CD8 cells. A tendency for recovery in numbers of this subset was seen after refeeding. A decreased memory:maive cell ratio was also seen among CD4 cells, but was less marked. Subtle abnormalities in activated CD4 and CD8 cells were also found in the patient group at the initial sampling, but did not follow any clear pattern. These findings indicate that starvation in anorexic patients is accompanied by a large change in memory CD8 T cells. It may be speculated that this relates to the perceived lack of symptomatic common viral infections in underweight anorexic patients and their return with the recovery of weight.

Sex differences in the corpus callosum with aging

The present study examined sex differences in the area and age-related atrophy of the corpus callosum (CC) of 76 healthy elderly subjects using magnetic resonance imaging. The cerebellum and pons served as noncortical control structures. CC area and its subregions were also related to cognitive performance. Women had a slightly larger posterior sector of the CC than men. Women but not men showed age-related atrophy of the anterior and middle sectors of the CC but not the posterior sector. Cerebellum and pons size was similar in men and women, and neither showed age-related atrophy. CC area was related to visual memory in women but not men; no other significant cognitive to structure area relationships were found. These findings show that selective age related atrophy of the CC differs in men and women late in life.

Genomic regions regulating imprinting and insulin-like growth factor-II promoter 3 activity in transgenics: novel enhancer and silencer elements

Transgenic lines (89) were made with constructs containing eight different combinations of candidate regulatory elements from the insulin-like growth factor-II (Igf2)-H19 region of mouse chromosome 7. In all constructs, promoter 3 of Igf2 was attached to a firefly luciferase reporter gene. Promoter 3 was the common element that imposed a decrease in reporter activity similar to that of endogenous Igf2 after birth. The specific activity of the reporter was measured on the day of birth in the liver and the brain, after each transgene had been transmitted by either the father or the mother. This procedure demonstrated that the quantity and organ distribution of expression from this promoter can be regulated by each element. The following new information was obtained. (a) The 5' differentially methylated region of Igf2 inhibits promoter 3 in the liver. (b) The conserved DNase I-hypersensitive Middle region between Igf2 and H19 is an enhancer of promoter 3 in the brain. (c) The H19 promoter inhibits Igf2 promoter 3 in the brain. The results confirmed that the H19 enhancer is a strong enhancer of promoter 3 in the liver. A new finding was that one genomic region regularly imposed imprinted gene expression. This was the H19 enhancer, and this region was sufficient to give higher expression on maternal transmission in the majority of transgenic lines. The full data are reported in Supplementary Publication SUP 50180 (8 pages), which has been deposited at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1997) 21, 8-10.

Beck-Wiedemann syndrome and Wilms' tumour

Patients with rare overgrowth disorders, such as Beck-Wiedemann syndrome and Simpson-Golabi-Behmel syndrome, are predisposed to embryonal tumours, including Wilms' tumour of the kidney. Therefore, these disorders offer a link between hyperplastic growth and cancer. Genetic lesions at chromosome 11p15 have been associated with Beck-Wiedemann syndrome and Wilms' tumour for several years and the presence of the gene encoding insulin-like growth factor-II (IGF-II) in this region has given rise to much speculation over the involvement of this factor in these growth defects. This speculation was heightened by genetic evidence for the involvement of genomic imprinting in Beck-Wiedemann syndrome and Wilms' tumour, combined with the discovery that the IGF-II gene is imprinted. Although there is a wealth of evidence linking the IGF signalling pathway with overgrowth and cancer, recent progress in the study of 11p15 and developments in our understanding of the mechanism of genomic imprinting indicate that additional imprinted genes located in this region also contribute to these growth disorders.

The demand for eating disorder care. An epidemiological study using the general practice research database

BACKGROUND

An epidemiological study of anorexia nervosa and bulimia nervosa in primary care was performed using the General Practice Research Database (GPRD).

METHOD

The GPRD was screened between 1988 and 1994 for newly diagnosed cases of anorexia nervosa and bulimia nervosa. The validity of the computer diagnosis was established by obtaining clinical details from a random sample of the general practitioners (GPs).

RESULTS

Incidence rates for detection of cases by GPs in 1993 was 4.2 per 100,000 population for anorexia nervosa, and 12.2 per 100,000 for bulimia nervosa. The relative risks of females to males was 40:1 for anorexia nervosa and 47:1 for bulimia nervosa. A threefold increase in the recording of bulimia nervosa was found from 1988 to 1993. Eighty per cent of anorexia nervosa cases and 60% of bulimia nervosa cases were referred to secondary care.

CONCLUSION

There is a continuing expansion of service need for bulimia nervosa. The majority of cases of eating disorders are referred to secondary services. There is scope for more effective management of bulimia nervosa in primary care.

Improved quality of life in patients with generalized cardiovascular metabolic disease on a prepared diet

Current dietary recommendation for cardiovascular disease risk reduction and recommended dietary allowances (RDAs) were used to develop a nutritionally complete prepackaged prepared meal plan specifically designed to reduce the risk of cardiovascular disease. In the current study we tested patient acceptance of the diet as defined by measures of quality of life. In a randomized, parallel-design, multicenter clinical trial, 77 persons with hypertension, diabetes mellitus, dyslipidemia, or a combination of two or more of these conditions were recruited and randomly assigned to either a prepared meal plan (n = 39) or a comparable self-selected diet (n = 38) for 10 wk. The prepared meal plan met both the RDAs for all essential micronutrients and the dietary recommendations of national health organizations for macronutrients, cholesterol, sodium, and fiber. The prescribed self-selected diet was matched for macronutrients. Quality of life, as measured by a battery of instruments, was the major endpoint. Individuals consuming the prepared meal plan had significant improvements in mental health (P < 0.01), general perceived health (P < 0.005), daily activities (P < 0.05), work performance (P < 0.005), affect (P < 0.01), and nutritional health perceptions (P < 0.001), and reductions in nutrition hassles based on a standardized questionnaire (P < 0.001). The self-selected-diet group had significant improvements in nutritional health perceptions (P < 0.001) and affect (P < 0.001). There were significant improvements in weight (P < 0.001), blood pressure (P < 0.001), cholesterol (P < 0.002), low-density lipoproteins (P < 0.001), glucose (P < 0.014), and glycated hemoglobin (Hb A(1c) (P < 0.004) that were comparable in both groups. In summary, this study shows that a nutritionally complete diet, whether prepackaged or self-selected, improves multiple risk factors for cardiovascular disease. The prepackaged prepared meal plan had the added benefit of a greater improvement in quality of life.

Downgaze paresis following severe head trauma in a child

A 4 1/2-year-old girl developed a downgaze paresis following severe head trauma. Magnetic resonance imaging showed evidence of peri-aqueductal lesions in the rostral midbrain in the region of the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF). Twenty five weeks following the injury, the downgaze paresis remained unchanged but she developed convergence retraction nystagmus on attempted upgaze. Repeat imaging did not show any change in the lesions in the rostral midbrain. This report provides further evidence for the riMLF in the control of downgaze, and a synkinesis is postulated for the development of the convergence retraction nystagmus.

A novel target for the Wilms' tumour suppressor protein (WT1) is bound by a unique combination of zinc fingers

All isoforms of the Wilms' tumour suppressor protein, WT1, contain four consecutive zinc fingers which facilitate DNA binding. The predominant WT1 transcript contains a 9 base pair insertion resulting in an additional three amino acids, lysine-threonine-serine (KTS), between zinc fingers 3 and 4. WT1 zinc fingers 2, 3 and 4 are highly homologous to the zinc fingers of the early growth response gene, EGR1. However, only WT1--KTS is capable of binding an EGR1 consensus site. In contrast, the previously described genomic fragment, +P5 (D1S3309E), is bound by both WT1--KTS and WT1 + KTS. In this study, the region within + P5 to which both WT1 -- KTS and WT1 + KTS bind was defined as 5'-GGAGAGGGAGGATC-3'. EGR1 did not bind + P5. By creating zinc finger deletions, we demonstrate that zinc finger 1, but not zinc finger 4, is critical for + P5 binding; whereas zinc finger 4, but not 1, is necessary for the binding of WT1 target sites within EGR1, PDGF A chain and IGF2 promoters. Thus, zinc finger usage can vary with target and + P5 may represent a novel type of WT1 binding site, the physiological relevance of which must be investigated.