32P-postlabelling analysis of DNA adducts and EROD induction as biomarkers of genotoxin exposure in dab (Limanda limanda) from British coastal waters

Dab (Limanda limanda) were sampled from a number of polluted and unpolluted areas in British coastal waters. The 32P-postlabelling assay was used to analyse the level of aromatic/hydrophobic DNA adducts in pooled samples of liver tissue. The mean levels of DNA adducts detected from areas known to receive anthropogenic pollutants ranged from 4.0 to 26.8 adducts per 10(8) nucleotides, with all sites containing samples displaying DNA adduct profiles consisting of diagonal radioactive zones. In contrast no DNA adducts were detectable in samples from an unpolluted reference site. The ranking of polluted sites based on DNA adduct levels did not correspond with the ranking of sites based on sediment associated polycyclic aromatic hydrocarbon levels, highlighting the problem of linking the presence of contamination with detectable biological responses. No correlation could be found in this study between EROD activity and the level of DNA adducts.

Determining the validity of advance directives

We examine the ethical principles underpinning advance directives (ADs) and the legal duties of doctors in determining their validity. A physician attending an incompetent patient with an acute life-threatening illness, and an AD refusing treatment, should ensure that the AD is legally valid before making the treatment decision. Treatment against a patient's wishes, as expressed in a valid AD, compromises patient autonomy and may constitute battery. Conversely, withholding treatment in accordance with an AD that is not legally valid risks substantial harm to the patient and may constitute breach of the duty of care and negligence. Legally valid directives should be respected. If an AD is not legally valid, the patient should be treated in his or her best interests. If uncertain, the physician should treat according to the patient's best interests while seeking legal advice.

Setting up a multidisciplinary clinic

Chronic pelvic pain can be a perplexing and complex problem, frustrating to both clinicians and patients. The traditional medical and surgical model does not always relieve symptoms, and many patients suffer years of pain and undergo multiple surgical procedures without long-term benefit. The biopsychosocial model for chronic pelvic pain gives clinicians the opportunity to broaden the scope for management. A multidisciplinary team can offer simultaneous assessment and management of somatic, behavioural and psychosocial components of the pain. Key members of the team are identified and their roles explored. Practical aspects of operating a multidisciplinary clinic are discussed. A multidisciplinary approach comprises many elements. Further research is needed to identify which are the essential elements to secure optimum outcome for the individual patient.

Challenges in the dietary treatment of cystic fibrosis related diabetes mellitus

Cystic fibrosis related diabetes mellitus is an increasingly recognized problem as survival in patients with cystic fibrosis improves. In a 5 year retrospective study of 627 children and adults attending Toronto cystic fibrosis clinics, we identified 57 (9%) patients with cystic fibrosis related diabetes mellitus; four (1.3%) of 301 children (<18 years) and 53 (16%) of 326 adults. The development of this complication of cystic fibrosis is associated with increased mortality, deteriorations in both respiratory and nutritional status, and the development of late microvascular, but not macrovascular, diabetic complications. Unfortunately, systematic review of the literature provides few well designed studies that provide sound evidence for clinical practice. Recommendations are therefore often based on anecdote, rather than physiological or outcomes research. Dietary therapy combines the principles of the dietary management of both cystic fibrosis and diabetes mellitus, but emphasizes the need for a high energy diet (> 100% of recommended daily intake) in patients with cystic fibrosis related diabetes mellitus. The importance of calories from fat is emphasized, with no restriction on total carbohydrate intake. Insulin intake mirrors carbohydrate intake. Routine dietary therapy is straightforward, but challenges occur due to both complications of cystic fibrosis and advancing disease. If a patient with cystic fibrosis related diabetes mellitus is malnourished, overnight enteral tube feeding is often used, with an adjusted insulin regimen. There is a great need for both physiological and outcomes research to provide sound scientific evidence for the dietary treatment of cystic fibrosis related diabetes mellitus.

Urinary tract infection prophylaxis using Escherichia coli 83972 in spinal cord injured patients

PURPOSE

Escherichia coli 83972 was previously shown to establish bladder colonization in select patient groups. We evaluate the safety and feasibility of using bacterial interference with E. coli 83972 to prevent urinary tract infection in spinal cord injured patients.

MATERIALS AND METHODS

A total of 21 men and women with neurogenic bladder secondary to spinal cord injury underwent intravesical inoculation with E. coli 83972. Frequency of symptomatic urinary tract infection before and after colonization was compared.

RESULTS

Successful long-term bladder colonization was achieved in 13 study participants. Mean duration of colonization was 12.3 months (range 2 to 40). Subjects had no symptoms of urinary tract infection while colonized with E. coli 83972 (0 infection per 18.4 patient-years). Successfully colonized subjects had experienced a mean of 3.1 symptomatic urinary tract infections per year (range 2 to 7) before colonization. Symptomatic infection also occurred in 4 subjects who were not successfully colonized with E. coli 83972 and in 7 others after spontaneous loss of colonization. Colonized subjects reported subjective improvement in quality of life with respect to urinary tract infection while colonized.

CONCLUSIONS

E. coli 83972 may be safely used to establish long-term asymptomatic bladder colonization in spinal cord injured subjects. Preliminary findings suggest that colonization with E. coli 83972 may reduce the frequency of urinary tract infection in patients with neurogenic bladder secondary to spinal cord injury.

Comparative in vitro activity of gatifloxacin, grepafloxacin, levofloxacin, moxifloxacin and trovafloxacin against 4151 Gram-negative and Gram-positive organisms

Gatifloxacin, grepafloxacin, moxifloxacin and trovafloxacin are fluoroquinolones with enhanced Gram-positive activity while retaining broad-spectrum activity against Gram-negative pathogens. Levofloxacin and ciprofloxacin are older quinolones with broad activity against Gram-negative pathogens and borderline activity against some Gram-positive organisms. We compared the in vitro activity of these compounds against 4151 Gram-negative and -positive organisms. Gatifloxacin, grepafloxacin, moxifloxacin and trovafloxacin were highly active against penicillin sensitive and resistant Streptococcus pneumoniae, Staphylococcus aureus, Streptococcus pyogenes and Streptococcus agalactiae. Ciprofloxacin and levofloxacin were active but less potent. All compounds were highly active (overall) against Gram-negative pathogens with ciprofloxacin being the most active agent against Pseudomonas aeruginosa. Our data indicate that the advanced fluoroquinolones will be important compounds for treating infections caused by Gram-positive and Gram-negative pathogens.

Increased oxidative stress brought on by pro-inflammatory cytokines in neurodegenerative processes and the protective role of nitrone-based free radical traps

Nitrone-based free radical traps (NFTs) have been shown to be protective in several neurodegenerative models. Our research has strongly implicated that: A) several neurodegenerative conditions exhibit increased levels of pro-inflammatory cytokines which consequently result in increased levels of oxidative stress and B) that NFTs act in part by suppressing oxidative stress through suppression of the action of the cytokine cascade. Acquired Immune Deficiency Syndrome (AIDS) dementia complex (ADC) is one of several conditions where the data collected helped to develop these concepts. Novel observations include demonstration that IL-1beta acts on cultured brain glia cells to invoke protein nitration and oxidative stress and that low levels of PBN (alpha-phenyl tert-butyl nitrone) inhibit this effect. We interpret these data as indicating that PBN prevents IL-1beta mediated peroxynitrite formation. Additionally, we have found that the AIDS viral envelope protein gp120 upregulates mRNA for the cytokines TNF alpha and TNF beta in rat neonatal brain, and that PBN prevents this. Western blots of protein extracts showed upregulation of inducible nitric oxide synthase (iNOS) in gp120 treated neonatal rat brains, and that PBN prevented induction of this enzyme as well. These observations underscore the general concept that PBN inhibits the induction of genes which produce neurotoxic products, one of which is peroxynitrite formed by the reaction of nitric oxide with superoxide, and may act also by inhibiting the induction of cytokines which mediate pro-inflammatory conditions in the brain.

Effect of vitamin intervention on the relationship between GSTM1, smoking, and lung cancer risk among male smokers

The GSTM1 (glutathione S-transferase mu-1) null genotype is suspected of increasing an individual's susceptibility to tobacco smoke carcinogens because of impaired carcinogen detoxification. We were interested in whether there were differences in lung cancer susceptibility to smoking within the GSTM1 genotypes and the impact of antioxidant supplementation on this. For this purpose, we conducted a nested lung cancer case-control study and evaluated the role of GSTM1 within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. GSTM1 genotype status was determined for 319 cases and 333 controls using a PCR-based approach. GSTM1 was evaluated as an independent risk factor and as an effect modifier of smoking using logistic regression analyses. The GSTM1 null genotype itself was unrelated to risk of lung cancer, odds ratio (OR) = 1.09 and 95% confidence interval (CI), 0.79-1.50, but it may have modified the effect of smoking. There was a suggestion for a stronger association between years of smoking and lung cancer among the GSTM1 null genotype, but the differences between GSTM1 null and present genotypes were not statistically significant (P = 0.12). Furthermore, the smoking association was strongest among those with the GSTM1 null genotype not receiving alpha-tocopherol supplementation, whereas among those receiving alpha-tocopherol, there was no modification by GSTM1 on the association between smoking duration and lung cancer risk. Beta-carotene supplementation did not modify the relationship between GSTM1, smoking years, and lung cancer risk. In conclusion, GSTM1 is not associated with lung cancer risk in male smokers but may confer a higher susceptibility to cumulative tobacco exposure. This association may be attenuated by alpha-tocopherol but not by beta-carotene supplementation.

The detection of biomarkers of genotoxin exposure in the European flounder (Platichthys flesus) collected from the River Tyne Estuary

The Tyne Estuary (North East England) is known to contain elevated levels of polycyclic aromatic hydrocarbons (PAH), compared with other less industrialised English waterways. Previous studies suggest that such contamination is responsible for the toxicity detected in invertebrate bioassays conducted on water and sediment samples collected from the Tyne. Here we present data from a biomonitoring study using hepatic DNA adducts (32P-postlabelling assay) and bile metabolites (synchronous fluorescence spectrometry) to investigate genotoxic exposure in flounder (Platichthys flesus) collected from three sites (Scotswood, Newcastle and Redheugh) along the Tyne Estuary. Flounder were also collected from a clean reference site, the Alde Estuary. Levels of bile metabolites (microgram kg-1 wet weight 1-OH pyrene equivalents) were elevated in flounder caught from the Tyne (Scotswood = 22,247 +/- 3408; Newcastle = 14,572 +/- 1888; Redheugh = 21,872 +/- 2935) compared with those collected from the Alde (632 +/- 56). The levels of DNA adducts (adducted nucleotides per 10(8) normal nucleotides) were also elevated in Tyne flounder (Scotswood = 24.6 +/- 3.2; Newcastle = 34.4 +/- 3.7; Redheugh = 27.6 +/- 6.3) compared with fish collected from the Alde (10.1 +/- 4.8), suggesting that a proportion of the bioavailable PAH was being converted into genotoxic metabolites. All DNA adduct profiles in flounder collected from the Tyne consisted of diagonal radioactive zones of radiolabelled adducts, which were not present in fish sampled from the Alde. The in vivo dosing of flounder with benzo[a]pyrene (BaP) to produced DNA adducts in similar chromatographic positions to the diagonal radioactive zones in the Tyne caught flounder are also described.

Prevalence of disease-related DNA polymorphisms among participants in a large cancer prevention trial

Genetic susceptibility polymorphisms may be of substantial importance in the modulation of cancer risk. The prevalence for an array of polymorphic genes was determined in a cohort of male smokers who participated in a cancer prevention trial in Finland. A random sample of 120 individuals was selected from the trial cohort and the prevalence of variant alleles for nine genes was determined using a polymerase chain reaction-based approach. The prevalence values from this study were also compared with those of other populations derived from previous studies. Our results show that, with the exception of cytochrome P450-1A1 (CYP1A1) and cytochrome P450-2E1 (CYP2E1), all genes tested were sufficiently polymorphic to warrant an investigation of gene-environment studies. Most of the variant alleles, including alcohol dehydrogenase 3 (ADH3), glutathione-S-transferase (GSTM1), methionine synthase (MS), methylene tetrahydofolater reductase (MHTFR), CYP2E1 and CYP1A1, exhibited similar frequencies to other Caucasian populations. Interestingly, the prevalence of androgen receptor-CAG repeat (AR-CAG) and vitamin D receptor (VDR) polymorphisms differed significantly between the alpha-tocopherol, beta-carotene (ATBC) Study and other Caucasian populations. We present herein results from this survey and conclude that the ATBC study population in Finland is sufficiently heterogeneous to facilitate analysis of genetic polymorphisms and disease associations.

The use of dexamethasone in women with preterm premature rupture of membranes--a multicentre, double-blind, placebo-controlled, randomised trial. Dexiprom Study Group

OBJECTIVE

To assess whether administration of dexamethasone in women with preterm premature rupture of membranes (PPROM) has an effect on the prevalence of maternal sepsis, neonatal respiratory distress syndrome (RDS), perinatal mortality and neonatal sepsis in a developing country.

SETTING

Six public hospitals in South Africa that deal mainly with indigent women.

METHOD

A multicentre, double-blind, placebo-controlled, randomised trial was performed on women with PPROM and fetuses of 28-34 weeks' gestation or clinically estimated fetal weight between 1,000 and 2,000 g if the gestational age was unknown. Women were randomised to receive either dexamethasone 24 mg intramuscularly or placebo in two divided doses 24 hours apart. All women received amoxycillin and metronidazole and were managed expectantly. Hexoprenaline was administered if contractions occurred within the first 24 hours after admission to the trial.

OUTCOME MEASURES

The maternal outcome measures were clinical chorio-amnionitis and postpartum sepsis. The outcome measures for infants were perinatal death, RDS, mechanical ventilation, necrotising enterocolitis, and neonatal infection within 72 hours.

RESULTS

One hundred and two women who delivered 105 babies were randomised to the dexamethasone group and 102 women who delivered 103 babies, to the placebo group. The groups were well balanced with regard to clinical features. There was a trend towards fewer perinatal deaths in the dexamethasone group: 4 compared with 10 (P = 0.16, odds ratio 0.37, 95% confidence intervals 0.09-1.34). A subanalysis of mothers who delivered more than 24 hours after admission to the study and their infants revealed a significant reduction in perinatal deaths; 1 death in the dexamethasone group and 7 in the placebo group, P = 0.047 (Fisher's exact test). No woman in either group developed severe sepsis, and the incidence of sepsis in the women did not differ significantly. Eleven infants in each group developed sepsis.

CONCLUSION

This is the first randomised trial in women with PPROM to compare the effects of the use of corticosteroids with placebo, where all women received prophylactic antibiotics concomitantly with the corticosteroids. A trend towards an improved perinatal outcome was demonstrated in the women who received dexamethasone. There was no increased risk of infection in the women or their infants where dexamethasone was administered. Administration of corticosteroids to women with PPROM has more advantages than disadvantages in developing countries.

An assessment of the genotoxic impact of the Sea Empress oil spill by the measurement of DNA adduct levels in selected invertebrate and vertebrate species

The grounding of the Sea Empress oil tanker resulted in the release of 72,000 tonnes of crude oil into Milford Haven, Wales, UK. Our initial studies indicated that this contamination resulted in elevated levels of DNA adducts in one of the area's native marine species Lipophrys pholis [B.P. Lyons, J.S. Harvey, J.M. Parry, An initial assessment of the genotoxic impact of the Sea Empress oil spill by the measurement of DNA adduct levels in the intertidal teleost Lipophrys pholis, Mutat. Res. 390 (1997) 263-268]. These original studies were extended and the genotoxic impact of the oil contamination was investigated in the invertebrates Halichondria panicea and Mytilus edulis, along with the vertebrate fish species L. pholis, Pleuronectes platessa and Limanda limanda. DNA adduct levels were assessed in these species over a period of 2-17 months after the incident. The studies indicate differences in the impact of acute oil contamination upon vertebrate and invertebrate species. The oil contamination did not induce any detectable elevations in adduct levels in the invertebrate species H. panicea and M. edulis. In contrast, the oil contamination did appear to induce adducts in the vertebrate teleost species L. pholis, P. platessa and Lim. limanda. Despite some difficulties in sampling, the data obtained 12-17 months after the spill suggested that the affected species recovered from the oil contamination. While the studies indicate that the genetic impact of the oil contamination was less severe than might have been expected, it remains possible that the DNA adducts detected in the teleosts could lead to genetic changes in these species in the future.

Advanced directives, the right to die and the common law: recent problems with blood transfusions

The Australian common law suffers from a lack of judicial authority on the right to die, in particular the right of patients to make anticipatory decisions to refuse treatment. Recent cases concerning the right of patients to refuse life-saving blood transfusions have highlighted the need for a substantial judicial clarification of this area. This article critically examines one of the most recent Australian cases in detail and compares its approach with those from other common countries. After taking this comparative analysis the article puts forth a common law model of anticipatory decision-making and examines how that model might work in the context of current legislative frameworks.

Safe mobilization of normal progenitors in advanced chronic myeloid leukemia with intensive chemotherapy and granulocyte-colony stimulating factor

Twenty-one patients with advanced chronic myeloid leukemia (late chronic phase (n = 8), accelerated phase (n = 11) and blast crisis (n = 2)) were treated with idarubicin, cytarabine, and etoposide followed by G-CSF and subsequent collection of peripheral blood progenitor cells in the early recovery phase. Treatment was reasonably well tolerated with no deaths or intensive care admissions. Despite the advanced phase of disease and heavy pretreatment with cytotoxics and interferon-alfa, 11 of 21 patients (52%) achieved a cytogenetic response. Of the nine major cytogenetic responses (complete (n = 3) and partial (n = 6)), seven achieved adequate progenitor collections for consideration for autologous transplantation. The only predictor of response was disease duration (P = 0.02). With a median follow-up of 1171 days from treatment it appears unlikely that G-CSF contributed to disease progression. Survival post-IcE was predicted by disease stage (P = 0.0001). Intensive chemotherapy followed by G-CSF allowed adequate yields of predominantly Philadelphia chromosome negative progenitor cells to be obtained from one-third of patients with advanced CML.

Virulence properties of Escherichia coli 83972, a prototype strain associated with asymptomatic bacteriuria

Little is known about bacteria associated with asymptomatic bacteriuria (ABU) with regard to urinary tract colonization mechanisms. In this study, virulence properties of Escherichia coli 83972, a strain that was isolated from a clinical ABU episode, were examined. The genetic potential for expression of P and type 1 pili was demonstrated, and DNA sequences related to type 1C and G (UCA) pilus genes were also detected. However, E. coli 83972 did not express D-mannose-resistant or D-mannose-sensitive hemagglutination after growth under standard conditions in vitro or upon isolation from the urine of colonized test subjects. Limited uroepithelial cell adherence was observed in vivo, and weak D-mannose-sensitive hemagglutination was detected after extended growth in urine in vitro.

A 500-kb sequence-ready cosmid contig and transcript map of the MEN1 region on 11q13

We have generated a transcript map of an approximately 1.2-Mb region from human chromosome band 11q13 between the loci VEGFB and CAPN1, which flank the multiple endocrine neoplasia type 1 (MEN 1) locus. In total, we isolated 144 cosmids from this region and generated a sequence-ready cosmid contig of the approximately 500-kb region between the neurexin locus and D11S2196E. We identified 54 genes/ESTs by sample sequencing and have constructed a transcript map of this region. Genes were found to be clustered in three regions, and one of these genes was identical to the recently identified MEN1 locus. Relative to the latter, we have mapped the positions of 13 known genes, 18 genes which show homology to genes from humans or other organisms, and 22 genes/ESTs that appear novel. In addition, we have ascertained the directions of transcription of some of these genes and have determined intergenic distances between many loci. Full characterization of some of these genes, as well as the novel ESTs, will be useful in identifying candidate genes for other diseases known to map to this chromosomal region.

Characterization of the mouse Men1 gene and its expression during development

The gene responsible for multiple endocrine neoplasia type 1 (MEN1), a heritable predisposition to endocrine tumours in man, has recently been identified. Here we have characterized the murine homologue with regard to cDNA sequence, genomic structure, expression pattern and chromosomal localisation. The murine Men1 gene spans approximately 6.7 kb of genomic DNA and is comprised of 10 exons with similar genomic structure to the human locus. It was mapped to the pericentromeric region of mouse chromosome 19, which is conserved with the human 11q13 band where MEN1 is located. The predicted protein is 611 amino acids in length and overall is 97% homologous to the human orthologue. The 45 reported MEN1 mutations which alter or delete a single amino acid in human all occur at conserved residues, thereby supporting their functional significance. Two transcripts of approximately 3.2 and 2.8 kb were detected in both embryonal and adult murine tissues, resulting from alternative splicing of intron 1. By RNA in situ hybridization and Northern analysis the spatiotemporal expression pattern of Men1 was determined during mouse development. Men1 gene activity was detected already at gestational day 7. At embryonic day 14 expression was generally high throughout the embryo, while at day 17 the thymus, skeletal muscle, and CNS showed the strongest signal. In selected tissues from postnatal mouse Men1 was detected in all tissues analysed and was expressed at high levels in cerebral cortex, hippocampus, testis, and thymus. In brain the menin protein was detected mainly in nerve cell nuclei, whereas in testis it appeared perinuclear in spermatogonia. These results show that Men1 expression is not confined to organs affected in MEN1, suggesting that Men1 has a significant function in many different cell types including the CNS and testis.

Mutant membrane protein toxicity

This report describes an extensive mutational analysis of the most carboxyl-terminal membrane-spanning sequence of Escherichia coli lac permease (TM12). In addition to identifying residues important for lactose transport function, the analysis revealed that numerous mutations made lac permease highly toxic to cells. In the most extreme cases, production of such proteins at very low steady-state levels reduced cell viability greater than 10(4)-fold. Both frameshift and missense mutations led to toxicity, with the frameshift mutations having the strongest effects observed. The toxic missense mutations corresponded to changes in TM12 expected to interfere with membrane insertion or folding, such as the introduction of charged residues or prolines in the putative helix. The results suggest that cellular toxicity may be a relatively common consequence of mutations altering integral membrane protein folding. An analogous toxicity might contribute to the pathogenesis of several degenerative diseases caused by mutant membrane proteins, such as retinitis pigmentosa, Charcot-Marie-Tooth syndrome, and Alzheimer's disease.

The true cost of treating children

Paediatric patients (compared with adults) require additional time, effort and skill from hospital staff caring for them. Many suggestions for making successive versions of AN-DRGs more child friendly have not been implemented. Rather than relying on age, the AN-DRG classification should allow a better definition of complexity within DRGs. The two groups of children who place a disproportionate burden on paediatric teaching centres are children under 3 years and those with congenital abnormalities and chronic illness. Cost weights are not specific for paediatric patients. The extra costs of caring for children are reflected in nursing costs, highlighting the importance of including nurse dependency data in any costing study.