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.

Immunochemical detection of arylamine N-acetyltransferase in normal and neoplastic bladder

The N-acetyltransferase (NAT) phenotype is an important determinant of individual susceptibility to occupational bladder cancer. N-Acetyltransferases arc known to metabolize aromatic amine bladder carcinogens, but the functional significance of NAT expression in the target organ is unclear. To resolve this issue, polygonal antisera against purified recombinant enzymes and C-terminal peptides of human NAT Type 1 (NAT1) and Type 2 (NAT2) were generated. Western blot analysis of exfoliated cells from human urine, pig bladder homogenate, and human bladder tumor-derived cell lines showed that NAT1 was expressed in all three systems, whereas NAT2 did not appear to be expressed in the bladder. Immunohistochemical analysis of human bladder tumor sections indicated that well-differentiated tumor cells expressed NAT1, with the highest level of expression being found in the umbrella cells that line the bladder lumen. Poorly differentiated tumor regions appeared to express NAT1 at lower levels than did well-differentiated areas. These findings support the hypothesis that aromatic amines are metabolized in the bladder epithelium by NAT1.

RNA binding by the Wilms tumor suppressor zinc finger proteins

The Wilms tumor suppressor gene WT1 is implicated in the ontogeny of genito-urinary abnormalities, including Denys-Drash syndrome and Wilms tumor of the kidney. WT1 encodes Kruppel-type zinc finger proteins that can regulate the expression of several growth-related genes, apparently by binding to specific DNA sites located within 5' untranslated leader regions as well as 5' promoter sequences. Both WT1 and a closely related early growth response factor, EGR1, can bind the same DNA sequences from the mouse gene encoding insulin-like growth factor 2 (Igf-2). We report that WT1, but not EGR1, can bind specific Igf-2 exonic RNA sequences, and that the zinc fingers are required for this interaction. WT1 zinc finger 1, which is not represented in EGR1, plays a more significant role in RNA binding than zinc finger 4, which does have a counterpart in EGR1. Furthermore, the normal subnuclear localization of WT1 proteins is shown to be RNase, but not DNase, sensitive. Therefore, WT1 might, like the Kruppel-type zinc finger protein TFIIIA, regulate gene expression by both transcriptional and posttranscriptional mechanisms.

Psychosocial influences on the use of health care by children

A prospective cohort study examined the influence of psychosocial factors on the use of general practitioners over a six-month period by 271 children (aged four to nine years) and their mothers. The study was conducted in 10 general practices in the metropolitan area of Perth. The influences of psychosocial factors on use, nonuse and frequency of use by the children were examined, taking into account sociodemographic and morbidity factors. Physical health status, maternal use and financial factors were directly associated with the children's use or nonuse of general practitioners, while maternal stress, a mother's attitude towards her child and the child's psychosocial morbidity were indirectly related. Physical health status, doctor-initiated consultations, maternal stress, children's ages and birth order were directly associated with the children's frequency of use of general practitioners. Depression and anxiety in the mothers, measured with standardised instruments, were not associated with use by the children nor was a mother's level of social support. The results point to the importance of family relationships and illness behaviour in the family when considering use of general practitioners and the importance of using standardised measuring instruments and multivariate designs when studying such complex behaviours as the use of health care.

To change or not to change--'how' is the question?

The objective was to apply the 'trans-theoretical' model of change to a group of patients with eating disorders. Patients were studied in an in-patient setting. Two sets of questionnaires were used, one to assess 'stage' of change, the other to measure the 'processes' used to achieve change. Three stages and eight processes were examined. Thirty-five patients completed the study. Highest scores were found in the contemplation, and lowest in the precontemplation stage. The most frequently used processes of change were self-reevaluation, helping relationships and consciousness raising, with different processes predominating at different stages. Covariance analysis supported an association between two latent variables 'stage' and 'process'. Despite the limitations of small numbers, our results are in broad agreement with others using the 'trans-theoretical' model, supporting its use in eating disorders. Although further work is necessary, the model suggests a way of thinking about helping this very ambivalent group of patients to institute and sustain change.

Arylamine N-acetyltransferase in erythrocytes of cystic fibrosis patients

Sulphamethoxazole, a substrate of human arylamine N-acetyltransferase, is used in the treatment of cystic fibrosis patients, who metabolise the drug rapidly. Increased metabolic clearance of sulphamethoxazole has been suggested to account for this rapid metabolism. Arylamine N-acetyltransferase type 1 is expressed in erythrocytes and leucocytes and the activity in erythrocytes is shown to contribute approximately 99% of the activity of arylamine N-acetyltransferase type 1 in blood cells. Arylamine N-acetyltransferase type 1 activity in erythrocytes from 16 adult cystic fibrosis patients and 19 age-matched controls were compared. Although there is a variation in erythrocyte arylamine N-acetyltransferase type 1 activity within each group, no difference was found when the two groups were compared. All individuals from the cystic fibrosis and control groups were investigated for certain allelic variants of the arylamine N-acetyltransferase type 1 gene (NAT1). Only one copy of a mutant NAT1 allele (NAT1*11) was found. The heterozygous NAT1 individual is a cystic fibrosis patient with a low level of erythrocyte arylamine N-acetyltransferase type 1 activity. A second distinct arylamine N-acetyltransferase isozyme, arylamine N-acetyltransferase type 2, is encoded at the multi-allelic NAT2 locus. There was no correlation between erythrocyte arylamine N-acetyltransferase-1 activity and NAT2 alleles present in either the cystic fibrosis or control groups. The distribution of NAT2 alleles was very similar in the two groups. The increased clearance of sulphamethoxazole in cystic fibrosis patients appears unlikely to be due to erythrocyte arylamine N-acetyltransferase type 1 activity or to inheritance of alleles at either the NAT1 or NAT2 loci.

Attitudes toward risk factor behavior of relatives of cancer patients

BACKGROUND

Targeted health promotion requires an identifiable subpopulation which is accessible, at increased risk, receptive to input, and receptive to change. Relatives of recently diagnosed cancer patients may meet these criteria and have not previously been investigated as recipients of preventive education regarding smoking and diet.

METHODS

This study investigates these factors, beliefs regarding perceived susceptibility to cancer, and attitudes toward behavior change in 101 relatives of 50 patients with smoking-related cancers, breast cancer, and other diet-related cancers. Congruence of attitudes between patients and relatives, another possible factor in changing health behaviors, also was assessed.

RESULTS

Access to relatives of patients was very high, as was their willingness to discuss these issues (99% of relatives contacted participated in the survey). Relatives' ratings of relevant risk factors were generally higher than those of patients; ratings of their own vulnerability were moderate. Within diagnostic groups, there was high concordance of belief between patients and relatives for certain types of risk, such as heredity for breast cancer (r = 0.81) and smoking for smoking-related cancers (r = 0.52), but not for dietary factors.

CONCLUSIONS

The high level of access suggests that relatives may be receptive to discussing issues of behavior risk and change. They are at least as aware as patients of cancer risk factors. Spontaneous behavior change was very low. They may therefore be good candidates for targeted health promotion regarding cancer risk.

Physical measures of recovery from anorexia nervosa during hospitalised re-feeding

OBJECTIVE

To examine the relationship between weight gain, changes in body composition and physiological characteristics of fitness during the recovery from anorexia nervosa.

DESIGN

Longitudinal over eight weeks of intensive inpatient re-feeding (Wk 0-8).

SETTING

The London Hospital Medical College.

SUBJECTS

Ten female patients who agreed to participate. Seven completed the protocol.

INTERVENTIONS

Dual-energy X-ray absorptiometry (dexa) and skinfold thickness measures at Wk 0 and 8. Weekly measures of peak expiratory flow rate and cycle ergometry (several variables relating to aerobic work recorded at rest and during cycling at low loads (0-60 W)). Blood samples for lactate and potassium measures, taken during cycling at Wk 0, 4 and 8 only.

RESULTS

(1) Body composition: Mean weight gain over eight weeks was 9.6 kg, dexa and skinfold measures showing fat gain to contribute 62% and 54%, respectively. Both methods showed significant changes in percentage body fat with refeeding (P < 0.01 and P < 0.001, respectively), however there were significant differences in results between methods before (P < 0.01) but not after (P = 0.2) refeeding. (2) Physiological function: Between weeks 0 and 8, mean peak expiratory flow rate rose to 85% of predicted values, cycle ergometry performance improved in six subjects (three never reached 60 W load), mean respiratory exchange ratio (RER) during cycling fell at 0 W and 20 W loads (both P < 0.05), and oxygen pulse increased at rest and 0 W load cycling (both P < 0.05), Wk 8 values being well below normal. Oxygen uptake at rest and all loads increased in line with body weight gain only. No significant changes were seen in heart rate or blood lactate and potassium levels.

CONCLUSIONS

(1) Lean body and fat mass increased significantly during eight weeks of refeeding. The methodological difference in initial body fat measurements requires further investigation. (2) The women had severely impaired physiological function. Variables studied were only slowly improving with refeeding, and work capacity was still well below normal.

Repression of promoters for the mouse insulin-like growth factor II-encoding gene (Igf-2) by products of the Wilms' tumour suppressor gene wt1

We have investigated actions of the Wilms' tumour suppressor zinc finger transcription factor, WT1, on promoters of the mouse insulin-like growth factor II-encoding gene (Igf-2). Two variant forms of WT1 repressed the two major Igf-2 promoters (P2 and P3) in transient transfection assays. WT1-binding sites were characterised in both these promoters and in the transcribed region downstream from P2, exon 2. In each of these regions, there was a pair of WT1-binding sites, and mutational analysis of the exon-2 sites indicated that both were required for full repression. Cooperative binding of WT1 to these sites might explain the dominant-negative mutations of WT1 observed in some Wilms' tumours and Denys-Drash syndrome cases.

Detection of the heat-stable toxin coding gene (ST-gene) in enterotoxigenic Escherichia coli: development of a colour amplified PCR detection system

Screening biological samples using the polymerase chain reaction (PCR) has obvious advantages compared with current molecular analytical methods based on gel electrophoresis and/or hybridisation, both of which are expensive and time-consuming, therefore the development of a PCR assay format that is applicable to large sample numbers and that can readily use equipment commonly found in diagnostic laboratories would be advantageous. This report describes the development of a colour amplified PCR detection system which is simple in design and could be universally applied to the detection of any DNA template. As an example, the system has been applied in the detection of the heat-stable toxin coding gene (ST-gene) from enterotoxigenic Escherichia coli (ETEC). The assay is sensitive, detecting 10 fg of a purified DNA template and 270 cfu of an ST-gene-positive ETEC strain.

Mammary cancer in transgenic mice expressing insulin-like growth factor II (IGF-II)

The effect of insulin-like growth factor II (IGF-II) on tumour development in the mouse mammary gland was studied. To promote extra IGF-II expression in the mammary gland, sheep beta-lactoglobulin regulatory elements were attached to the coding regions of the mouse Igf-2 gene and injected into the pronuclei of mouse zygotes. Mammary tumours developed in each of the four independent lines of mice which expressed transgene IGF-II in the gland. Tumours from two of the lines grew after transplantation to both male and female hosts. Primary tumours contained stromal and epithelial regions, but the tumours were dominated by mammary adenocarcinoma after transplantation. The tumours expressed high levels of Igf-2 mRNA transcribed from the integrated transgenes.