Evidence of Antineutrinos from Distant Reactors Using Pure Water at SNO

The SNO+ Collaboration reports the first evidence of reactor antineutrinos in a Cherenkov detector. The nearest nuclear reactors are located 240 km away in Ontario, Canada. This analysis uses events with energies lower than in any previous analysis with a large water Cherenkov detector. Two analytical methods are used to distinguish reactor antineutrinos from background events in 190 days of data and yield consistent evidence for antineutrinos with a combined significance of 3.5σ.

Genetic influences on eight psychiatric disorders based on family data of 4 408 646 full and half-siblings, and genetic data of 333 748 cases and controls

BACKGROUND

Most studies underline the contribution of heritable factors for psychiatric disorders. However, heritability estimates depend on the population under study, diagnostic instruments, and study designs that each has its inherent assumptions, strengths, and biases. We aim to test the homogeneity in heritability estimates between two powerful, and state of the art study designs for eight psychiatric disorders.

METHODS

We assessed heritability based on data of Swedish siblings (N = 4 408 646 full and maternal half-siblings), and based on summary data of eight samples with measured genotypes (N = 125 533 cases and 208 215 controls). All data were based on standard diagnostic criteria. Eight psychiatric disorders were studied: (1) alcohol dependence (AD), (2) anorexia nervosa, (3) attention deficit/hyperactivity disorder (ADHD), (4) autism spectrum disorder, (5) bipolar disorder, (6) major depressive disorder, (7) obsessive-compulsive disorder (OCD), and (8) schizophrenia.

RESULTS

Heritability estimates from sibling data varied from 0.30 for Major Depression to 0.80 for ADHD. The estimates based on the measured genotypes were lower, ranging from 0.10 for AD to 0.28 for OCD, but were significant, and correlated positively (0.19) with national sibling-based estimates. When removing OCD from the data the correlation increased to 0.50.

CONCLUSIONS

Given the unique character of each study design, the convergent findings for these eight psychiatric conditions suggest that heritability estimates are robust across different methods. The findings also highlight large differences in genetic and environmental influences between psychiatric disorders, providing future directions for etiological psychiatric research.

ASD and schizophrenia show distinct developmental profiles in common genetic overlap with population-based social communication difficulties

Difficulties in social communication are part of the phenotypic overlap between autism spectrum disorders (ASD) and schizophrenia. Both conditions follow, however, distinct developmental patterns. Symptoms of ASD typically occur during early childhood, whereas most symptoms characteristic of schizophrenia do not appear before early adulthood. We investigated whether overlap in common genetic influences between these clinical conditions and impairments in social communication depends on the developmental stage of the assessed trait. Social communication difficulties were measured in typically-developing youth (Avon Longitudinal Study of Parents and Children, N⩽5553, longitudinal assessments at 8, 11, 14 and 17 years) using the Social Communication Disorder Checklist. Data on clinical ASD (PGC-ASD: 5305 cases, 5305 pseudo-controls; iPSYCH-ASD: 7783 cases, 11 359 controls) and schizophrenia (PGC-SCZ2: 34 241 cases, 45 604 controls, 1235 trios) were either obtained through the Psychiatric Genomics Consortium (PGC) or the Danish iPSYCH project. Overlap in genetic influences between ASD and social communication difficulties during development decreased with age, both in the PGC-ASD and the iPSYCH-ASD sample. Genetic overlap between schizophrenia and social communication difficulties, by contrast, persisted across age, as observed within two independent PGC-SCZ2 subsamples, and showed an increase in magnitude for traits assessed during later adolescence. ASD- and schizophrenia-related polygenic effects were unrelated to each other and changes in trait-disorder links reflect the heterogeneity of genetic factors influencing social communication difficulties during childhood versus later adolescence. Thus, both clinical ASD and schizophrenia share some genetic influences with impairments in social communication, but reveal distinct developmental profiles in their genetic links, consistent with the onset of clinical symptoms.

The iPSYCH2012 case-cohort sample: new directions for unravelling genetic and environmental architectures of severe mental disorders

The Integrative Psychiatric Research (iPSYCH) consortium has established a large Danish population-based Case-Cohort sample (iPSYCH2012) aimed at unravelling the genetic and environmental architecture of severe mental disorders. The iPSYCH2012 sample is nested within the entire Danish population born between 1981 and 2005, including 1 472 762 persons. This paper introduces the iPSYCH2012 sample and outlines key future research directions. Cases were identified as persons with schizophrenia (N=3540), autism (N=16 146), attention-deficit/hyperactivity disorder (N=18 726) and affective disorder (N=26 380), of which 1928 had bipolar affective disorder. Controls were randomly sampled individuals (N=30 000). Within the sample of 86 189 individuals, a total of 57 377 individuals had at least one major mental disorder. DNA was extracted from the neonatal dried blood spot samples obtained from the Danish Neonatal Screening Biobank and genotyped using the Illumina PsychChip. Genotyping was successful for 90% of the sample. The assessments of exome sequencing, methylation profiling, metabolome profiling, vitamin-D, inflammatory and neurotrophic factors are in progress. For each individual, the iPSYCH2012 sample also includes longitudinal information on health, prescribed medicine, social and socioeconomic information, and analogous information among relatives. To the best of our knowledge, the iPSYCH2012 sample is the largest and most comprehensive data source for the combined study of genetic and environmental aetiologies of severe mental disorders.

COMT Val158Met and MTHFR C677T moderate risk of schizophrenia in response to childhood adversity

OBJECTIVE

Mesolimbic dopamine sensitization has been hypothesized to be a mediating factor of childhood adversity (CA) on schizophrenia risk. Activity of catechol-O-methyltransferase (COMT) Val158Met increases mesolimbic dopamine signaling and may be further regulated by methylenetetrahydrofolate reductase (MTHFR) C677T. This study investigates the three-way interaction between CA, COMT, and MTHFR.

METHODS

We conducted a nested case-control study on individuals born after 1981, linking population-based registers to study the three-way interaction. We included 1699 schizophrenia cases and 1681 controls, and used conditional logistic regression to report incidence rate ratios (IRRs).

RESULTS

Childhood adversity was robustly associated with schizophrenia. No main genetic effects were observed. MTHFR C677T increased schizophrenia risk in a dose-dependent manner per MTHFR T allele (P = 0.005) consequent upon CA exposure. After inclusion of the significant (P = 0.03) COMT × MTHFR × CA interaction, the risk was further increased per high-activity COMT Val allele. Hence, exposed COMT Val/Val and MTHFR T/T carriers had an IRR of 2.76 (95% CI, 1.66-4.61). Additional adjustments for ancestry and parental history of mental illness attenuated the results with the interaction being only marginally significant.

CONCLUSION

MTHFR C677T and COMT Val158Met interact with CA to increase risk of schizophrenia.

Whole-exome sequencing of individuals from an isolated population implicates rare risk variants in bipolar disorder

Bipolar disorder affects about 1% of the world's population, and its estimated heritability is about 75%. Only few whole genome or whole-exome sequencing studies in bipolar disorder have been reported, and no rare coding variants have yet been robustly identified. The use of isolated populations might help finding variants with a recent origin, more likely to have drifted to higher frequency by chance. Following this approach, we investigated 28 bipolar cases and 214 controls from the Faroe Islands by whole exome sequencing, and the results were followed-up in a British sample of 2025 cases and 1358 controls. Seventeen variants in 16 genes in the single-variant analysis, and 3 genes in the gene-based statistics surpassed exome-wide significance in the discovery phase. The discovery findings were supported by enrichment analysis of common variants from genome-wide association studies (GWAS) data and interrogation of protein-protein interaction networks. The replication in the British sample confirmed the association with NOS1 (missense variant rs79487279) and NCL (gene-based test). A number of variants from the discovery set were not present in the replication sample, including a novel PITPNM2 missense variant, which is located in a highly significant schizophrenia GWAS locus. Likewise, PIK3C2A identified in the gene-based analysis is located in a combined bipolar and schizophrenia GWAS locus. Our results show support both for existing findings in the literature, as well as for new risk genes, and identify rare variants that might provide additional information on the underlying biology of bipolar disorder.

High loading of polygenic risk in cases with chronic schizophrenia

Genomic risk profile scores (GRPSs) have been shown to predict case-control status of schizophrenia (SCZ), albeit with varying sensitivity and specificity. The extent to which this variability in prediction accuracy is related to differences in sampling strategies is unknown. Danish population-based registers and Neonatal Biobanks were used to identify two independent incident data sets (denoted target and replication) comprising together 1861 cases with SCZ and 1706 controls. A third data set was a German prevalent sample with diagnoses assigned to 1773 SCZ cases and 2161 controls based on clinical interviews. GRPSs were calculated based on the genome-wide association results from the largest SCZ meta-analysis yet conducted. As measures of genetic risk prediction, Nagelkerke pseudo-R(2) and variance explained on the liability scale were calculated. GRPS for SCZ showed positive correlations with the number of psychiatric admissions across all P-value thresholds in both the incident and prevalent samples. In permutation-based test, Nagelkerke pseudo-R(2) values derived from samples enriched for frequently admitted cases were found to be significantly higher than for the full data sets (Ptarget=0.017, Preplication=0.04). Oversampling of frequently admitted cases further resulted in a higher proportion of variance explained on the liability scale (improvementtarget= 50%; improvementreplication= 162%). GRPSs are significantly correlated with chronicity of SCZ. Oversampling of cases with a high number of admissions significantly increased the amount of variance in liability explained by GRPS. This suggests that at least part of the effect of common single-nucleotide polymorphisms is on the deteriorative course of illness.

CACNA1C hypermethylation is associated with bipolar disorder

The CACNA1C gene, encoding a subunit of the L-type voltage-gated calcium channel is one of the best-supported susceptibility genes for bipolar disorder (BD). Genome-wide association studies have identified a cluster of non-coding single-nucleotide polymorphisms (SNPs) in intron 3 to be highly associated with BD and schizophrenia. The mechanism by which these SNPs confer risk of BD appears to be through an altered regulation of CACNA1C expression. The role of CACNA1C DNA methylation in BD has not yet been addressed. The aim of this study was to investigate if CACNA1C DNA methylation is altered in BD. First, the methylation status of five CpG islands (CGIs) across CACNA1C in blood from BD subjects (n=40) and healthy controls (n=38) was determined. Four islands were almost completely methylated or completely unmethylated, while one island (CGI 3) in intron 3 displayed intermediate methylation levels. In the main analysis, the methylation status of CGI 3 was analyzed in a larger sample of BD subjects (n=582) and control individuals (n=319). Out of six CpG sites that were investigated, five sites showed significant hypermethylation in cases (lowest P=1.16 × 10(-7) for CpG35). Nearby SNPs were found to influence the methylation level, and we identified rs2238056 in intron 3 as the strongest methylation quantitative trait locus (P=2.6 × 10(-7)) for CpG35. In addition, we found an increased methylation in females, and no difference between bipolar I and II. In conclusion, we find that CACNA1C methylation is associated with BD and suggest that the regulatory effect of the non-coding risk variants involves a shift in DNA methylation.

Genome-wide study of association and interaction with maternal cytomegalovirus infection suggests new schizophrenia loci

Genetic and environmental components as well as their interaction contribute to the risk of schizophrenia, making it highly relevant to include environmental factors in genetic studies of schizophrenia. This study comprises genome-wide association (GWA) and follow-up analyses of all individuals born in Denmark since 1981 and diagnosed with schizophrenia as well as controls from the same birth cohort. Furthermore, we present the first genome-wide interaction survey of single nucleotide polymorphisms (SNPs) and maternal cytomegalovirus (CMV) infection. The GWA analysis included 888 cases and 882 controls, and the follow-up investigation of the top GWA results was performed in independent Danish (1396 cases and 1803 controls) and German-Dutch (1169 cases, 3714 controls) samples. The SNPs most strongly associated in the single-marker analysis of the combined Danish samples were rs4757144 in ARNTL (P=3.78 × 10(-6)) and rs8057927 in CDH13 (P=1.39 × 10(-5)). Both genes have previously been linked to schizophrenia or other psychiatric disorders. The strongest associated SNP in the combined analysis, including Danish and German-Dutch samples, was rs12922317 in RUNDC2A (P=9.04 × 10(-7)). A region-based analysis summarizing independent signals in segments of 100 kb identified a new region-based genome-wide significant locus overlapping the gene ZEB1 (P=7.0 × 10(-7)). This signal was replicated in the follow-up analysis (P=2.3 × 10(-2)). Significant interaction with maternal CMV infection was found for rs7902091 (P(SNP × CMV)=7.3 × 10(-7)) in CTNNA3, a gene not previously implicated in schizophrenia, stressing the importance of including environmental factors in genetic studies.

Neonatal levels of neurotrophic factors and risk of autism spectrum disorders

OBJECTIVE

To examine levels of 3 neurotrophic factors (NTFs): Brain derived neurotrophic factor (BDNF), Neurotrophin-4 (NT-4), and transforming growth factor-β (TGF-β) in dried blood spot samples of neonates diagnosed with autism spectrum disorders (ASD) later in life and frequency-matched controls.

METHOD

Biologic samples were retrieved from the Danish Newborn Screening Biobank. NTFs for 414 ASD cases and 820 controls were measured using Luminex technology. Associations were analyzed with continuous measures (Tobit regression) as well as dichotomized at the lower and upper 10th percentiles cutoff points derived from the controls' distributions (logistic regression).

RESULTS

ASD cases were more likely to have BDNF levels falling in the lower 10th percentile (odds ratios [OR], 1.53 [95% confidence intervals (CI), 1.04-2.24], P-value = 0.03). Similar pattern was seen for TGF-β in females with ASD (OR, 2.36 [95% CI, 1.05-5.33], P-value = 0.04). For NT-4, however, ASD cases diagnosed with ICD-10 only were less likely to have levels in upper 10th percentile compared with controls (OR, 0.22 [95% CI, 0.05-0.98], P-value = 0.05).

CONCLUSION

Results cautiously indicate decreased NTFs levels during neonatal period in ASD. This may contribute to the pathophysiology of ASD through impairments of neuroplasticity. Further research is required to confirm our results and to examine the potential therapeutic effects of NTFs in ASD.

The effects of low to moderate prenatal alcohol exposure in early pregnancy on IQ in 5-year-old children

OBJECTIVE

To examine the effects of low to moderate maternal alcohol consumption during early pregnancy on children's intelligence (IQ) at age 5 years.

DESIGN

Prospective follow-up study.

SETTING

Neuropsychological testing in four Danish cities 2003-2008.

POPULATION

A cohort of 1628 women and their children sampled from the Danish National Birth Cohort.

METHODS

Participants were sampled based on maternal alcohol consumption during pregnancy. At 5 years of age, children were tested with the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R). Parental education, maternal IQ, maternal smoking in pregnancy, the child's age at testing, gender, and tester were considered core confounding factors, whereas the full model also controlled for maternal binge drinking, age, BMI, parity, home environment, postnatal smoking in the home, health status, and indicators for hearing and vision impairments.

MAIN OUTCOME MEASURES

The WPPSI-R.

RESULTS

No differences in test performance were observed between children whose mothers reported consuming between one and four or between five and eight drinks per week at some point during pregnancy, compared with children of mothers who abstained. For women who reported consuming nine or more drinks per week no differences were observed for mean differences; however, the risks of low full-scale IQ (OR 4.6; 95% CI 1.2-18.2) and low verbal IQ (OR 5.9; 95% CI 1.4-24.9) scores, but not low performance IQ score, were increased.

CONCLUSIONS

Maternal consumption of low to moderate quantities of alcohol during pregnancy was not associated with the mean IQ score of preschool children. Despite these findings, acceptable levels of alcohol use during pregnancy have not yet been established, and conservative advice for women continues to be to avoid alcohol use during pregnancy.

The effects of low to moderate alcohol consumption and binge drinking in early pregnancy on selective and sustained attention in 5-year-old children

OBJECTIVE

The aim was to examine the effects of low to moderate maternal alcohol consumption and binge drinking in early pregnancy on children's attention at 5 years of age.

DESIGN

Prospective follow-up study.

SETTING

Neuropsychological testing in four Danish cities 2003-2008.

POPULATION

A cohort of 1628 women and their children sampled from the Danish National Birth Cohort.

METHODS

Participants were sampled based on maternal alcohol consumption during pregnancy. At 5 years of age, the children were tested with the recently developed Test of Everyday Attention for Children at Five (TEACh-5). Parental education, maternal IQ, maternal smoking in pregnancy, the child's age at testing, gender, and tester were considered core confounding factors, whereas the full model also controlled the following potential confounding factors: maternal binge drinking or low to moderate alcohol consumption, age, body mass index (BMI), parity, home environment, postnatal smoking in the home, child's health status, and indicators for hearing and vision impairments.

MAIN OUTCOME MEASURES

TEACh-5 attention scores.

RESULTS

There were no significant effects on test performance in children of mothers drinking up to 8 drinks per week compared with children of mothers who abstained, but there was a significant association between maternal consumption of 9 or more drinks per week and risk of a low overall attention score (OR 3.50, 95% CI 1.15-10.68). No consistent or significant associations were observed between binge drinking and attention test scores.

CONCLUSIONS

The findings suggest an effect of maternal consumption of 9 or more drinks per week on attention functions in children, but the study detected no effects of lower levels of maternal consumption and no consistent effects of maternal binge drinking.

The effect of age on the hydroxylation of amylobarbitone sodium in man

1 Following a single oral dose of amylobarbitone sodium it has been shown that a group of young subjects convert a higher proportion of the dose to 3'-hydroxyamylobarbitone than a group of elderly subjects. 2 Twenty-four hours after the administration of the drug, the mean plasma level of amylobarbitone in the elderly group is significantly higher than in the group of young subjects. 3 It is concluded that the rate of hydroxylation of amylobarbitone sodium decreases with age.

Risk of autism spectrum disorders in children born after assisted conception: a population-based follow-up study

OBJECTIVES

To assess the risk of autism spectrum disorders (ASD) in children born after assisted conception compared with children born after natural conception.

DESIGN

Population-based follow-up study.

SETTING

All children born alive in Denmark 1995-2003.

PARTICIPANTS

588,967 children born in Denmark from January 1995 to December 2003. Assisted conception was defined as in vitro fertilisation (IVF) with or without intracytoplasmic sperm injection and ovulation induction (OI) with or without subsequent insemination. Children exposed to IVF or OI were identified in the IVF Register and in the Danish Drug Prescription Register.

MAIN OUTCOME MEASURES

A diagnosis of ASD in the Danish Psychiatric Central Register.

RESULTS

33,139 (5.6%) of all children born in Denmark in 1995-2003 resulted from assisted conception, 225 of whom (0.68%) had a diagnosis of ASD. Of the 555,828 children born in this period after natural conception, 3394 (0.61%) had a diagnosis of ASD. The follow-up time was 4-13 years (median 9 years). In crude analyses, children born after assisted conception had an increased risk of a diagnosis of ASD: crude hazard rate ratio (HRR) 1.25 (95% CI 1.09 to 1.43). In analyses adjusting for maternal age, educational level, parity, smoking, birth weight and multiplicity, the risk disappeared: adjusted HRR 1.13. (95% CI 0.97 to 1.31). However, subgroup analyses that suggest possible associations in women who received follicle stimulating hormone indicate the need for further study.

DISCUSSION

This population-based follow-up study found no risk of ASD in children born after assisted conception.

Multiplicity and early gestational age contribute to an increased risk of cerebral palsy from assisted conception: a population-based cohort study

BACKGROUND

This paper assesses the risk of cerebral palsy (CP) in children born after assisted conception compared with children born after natural conception (NC).

METHODS

This population based follow-up study included all 588,967 children born in Denmark from 1995 to 2003. Assisted conception was defined as IVF, with or without ICSI, and ovulation induction (OI), with or without subsequent insemination.

RESULTS

There were 33 139 (5.6%) children born in Denmark from 1995 to 2003 as a result of assisted conception and through to June 2009, 1146 (0.19%) children received a CP diagnosis. Children born after assisted conception had an increased risk of a CP diagnosis, crude hazard rate ratio (HRR) 1.90 (95% CI: 1.57-2.31) compared with NC children. Divided into IVF and OI children compared with NC children, the risk was HRR 2.34 (95% CI: 1.81-3.01) and HRR 1.55 (95% CI: 1.17-2.06), respectively. When we included the intermediate factors multiplicity and gestational age in multivariate models, the risk of CP in assisted conception disappeared. In general, children with CP born after assisted conception had similar CP subtypes and co-morbidities as children with CP born after NC.

CONCLUSION

The risk of CP is increased after both IVF and OI. The increased risk of CP in children born after assisted conception, and in particular IVF, is strongly associated with the high proportion of multiplicity and preterm delivery in these pregnancies. A more widespread use of single embryo transfer warrants consideration to enhance the long-term health of children born after IVF.

Interrelationship of cytokines, hypothalamic-pituitary-adrenal axis hormones, and psychosocial variables in the prediction of preterm birth

BACKGROUND/AIMS

To examine the relationship of biological mediators (cytokines, stress hormones), psychosocial, obstetric history, and demographic factors in the early prediction of preterm birth (PTB) using a comprehensive logistic regression model incorporating diverse risk factors.

METHODS

In this prospective case-control study, maternal serum biomarkers were quantified at 9-23 weeks' gestation in 60 women delivering at <37 weeks compared to 123 women delivering at term. Biomarker data were combined with maternal sociodemographic factors and stress data into regression models encompassing 22 preterm risk factors and 1st-order interactions.

RESULTS

Among individual biomarkers, we found that macrophage migration inhibitory factor (MIF), interleukin-10, C-reactive protein (CRP), and tumor necrosis factor-alpha were statistically significant predictors of PTB at all cutoff levels tested (75th, 85th, and 90th percentiles). We fit multifactor models for PTB prediction at each biomarker cutoff. Our best models revealed that MIF, CRP, risk-taking behavior, and low educational attainment were consistent predictors of PTB at all biomarker cutoffs. The 75th percentile cutoff yielded the best predicting model with an area under the ROC curve of 0.808 (95% CI 0.743-0.874).

CONCLUSION

Our comprehensive models highlight the prominence of behavioral risk factors for PTB and point to MIF as a possible psychobiological mediator.

Validation of self-reported data on assisted conception in The Danish National Birth Cohort

BACKGROUND

An increasing number of children are born after assisted conception and in surveillance programmes information on mode of conception is often achieved via maternal self-report. We assessed the validity of self-reported assisted conception in The Danish National Birth Cohort (DNBC), a prospective pregnancy cohort. Here, the term assisted conception refers to IVF, ICSI, ovulation induction and insemination.

METHODS

We compared self-reported assisted conception in the DNBC to corresponding data from Danish national registers; the IVF Register and Danish Drug Prescription Register, providing method of conception in the entire population. In the DNBC, 101,042 women accepted the invitation in early pregnancy from 1996 to 2002. Our final study population comprised 88,151 DNBC women aged 20 years and older who participated in the first DNBC interview with a pregnancy resulting in a live born child.

RESULTS

In the DNBC, assisted conception was reported with a sensitivity of 83% and positive predictive value of 88%. Misclassification was largely explained by ambiguous phrasing of the DNBC interview question and interview skip patterns. Women with false negative reporting were more often multipara (P < 0.001) and older (P = 0.027 for IVF/ICSI and P = 0.002 for ovulation induction). The risk ratio (RR) for being born preterm in IVF/ICSI children was lower for children identified via the DNBC, RR 3.61 (95% confidence interval (CI) 3.31-3.94), than the IVF Register, RR 4.36 (95% CI 4.02-4.74).

CONCLUSIONS

There was a high positive predictive value of self-reported assisted conception in the DNBC, but the structure of the DNBC interview represented a problem and misclassification could introduce bias.

Asphyxia-related risk factors and their timing in spastic cerebral palsy

OBJECTIVE

To investigate the association of asphyxia-related conditions (reducing blood flow or blood oxygen levels in the fetus) with spastic cerebral palsy (CP) considering different gestational age groups and the timing of risk.

DESIGN

Population-based case-control study.

SETTING

Danish Cerebral Palsy Register in eastern Denmark and Danish Medical Birth Register.

POPULATION OR SAMPLE

271 singletons with spastic CP and 217 singleton controls, frequency matched by gestational age group, born 1982-1990 in eastern Denmark.

METHODS

Data were abstracted from medical records, and a priori asphyxia-related conditions and other risk factors were selected for analysis. Each factor was classified according to the time at which it was likely to first be present.

MAIN OUTCOME MEASURES

Spastic CP.

RESULTS

Placental and cord complications accounted for the majority of asphyxia conditions. In multivariate analysis, placental infarction was significantly associated with a four-fold increased risk for spastic quadriplegia and cord around the neck was significantly associated with a three-fold increased risk for spastic CP overall. The combination of placental infarction and being small for gestational age (SGA) afforded an especially high risk for spastic quadriplegia. Placental and cord complications were present in 21% of cases and 12% of controls.

CONCLUSIONS

The risk for spastic quadriplegia from placental infarction may be linked in some cases with abnormal fetal growth (17% of all children with spastic quadriplegia and 3% of control children both had an infarction and were SGA) -- suggesting an aetiologic pathway that encompasses both factors. The risk for spastic CP from cord around the neck is not accounted for by other prepartum or intrapartum factors we examined. Considering the relative timing of risk factors provides a useful framework for studies of CP aetiology.

Diagnosis of insulin resistance in hypertensive patients by the metabolic syndrome: AHA vs. IDF definitions

BACKGROUND

Subjects with the metabolic syndrome are accompanied by insulin resistance (IR). However, it is not clear how well the newly defined metabolic syndrome identifies IR specifically in hypertensive subjects.

AIMS

The purpose of the study was to evaluate the performance of the metabolic syndrome, defined by the American Heart Association (AHA) and the International Diabetes Federation (IDF) definitions, in identifying IR in hypertension.

METHODS

The analysis is a cross-sectional study. Totally, 228 hypertensive patients and 92 non-diabetic normotensive controls who received insulin suppressive tests for direct evaluation of their insulin sensitivity were included from the Stanford Asia and Pacific Program for Hypertension and IR. McNemar's tests were used to compare sensitivity and specificity of the AHA-defined with the IDF-defined metabolic syndrome in diagnosis of IR.

RESULTS

The sensitivity of the metabolic syndrome for IR in hypertension was 89.7% and the specificity 45.9% by the AHA definition. Using the IDF definition, the sensitivity was 77.6%, and the specificity increased to 63.5%. The diagnostic power of individual components of the syndrome was also modest. The predictive discrimination of wider waist circumference was similar to that of the AHA-defined metabolic syndrome.

CONCLUSIONS

Use of the metabolic syndrome by the AHA definition provided good sensitivity, but low specificity to diagnose IR in hypertension. The IDF definition improved in false-positive rate, but it was still not specific enough to identify IR in hypertension.

Spray pattern analysis for metered dose inhalers I: Orifice size, particle size, and droplet motion correlations

Factors that influence spray pattern measurements of pressurized, metered-dose inhalers have been evaluated. Spray patterns were correlated with changes in actuator orifice diameter, particle size profiles, and calculated estimates of particle-size dynamics of plumes during a spray. Spray patterns, regardless of actuator orifice size, were ellipsoid in the vertical direction. Measures of elliptical ratio, major axis, and minor axis were significantly influenced by orifice size in a non-linear fashion over the range of orifice sizes investigated. Spray patterns also correlated with particle size profile and spray geometry measurements. Spray distribution asymmetry may be related to droplet evaporation and sedimentation processes. However, the spray patterns did not appear sensitive to changes in gravitational force acting on the plume. Instead, it is postulated that elliptical spray patterns may have dependence on fluid dynamic processes within the inhaler actuator. Developing an understanding of these processes may provide a basis for developing spray pattern tests with relevance to product performance.

Surrogate estimates of insulin sensitivity in subjects with hypertension

The purpose of the study is to compare surrogate estimates of insulin sensitivity with a directly measured insulin sensitivity index, steady-state plasma glucose (SSPG) from insulin suppression test (IST), in subjects with hypertension. Two hundred and twenty-eight hypertensive patients who received IST for SSPG were included for analysis. Estimates from fasting measurements alone, homeostasis model assessment for insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI)), and indices from fasting and/or 2 h samples (ISI(0,120) and ISI(TX)) were calculated. In addition to Pearson and partial correlations, variance-component models were used to test the relationship between surrogate estimates of insulin sensitivity and SSPG. A large proportion of variance owing to covariates in the variance-component models indicated the goodness of model fit, irrespective of the independence among variables. SSPG was positively correlated with logarithmic transformation (Log) (HOMA-IR) and negatively correlated with QUICKI, Log (ISI(0,120)) and ISI(TX) (all P<0.0001). Log (ISI(0,120)) seemed to have a better correlation with SSPG (r=-0.72) than other measures in partial correlation. The proportion of variance owing to all covariates of Log (ISI(0,120)) and ISI(TX) were larger than those of Log (HOMA-IR) and QUICKI in the variance-component models. After adjustments for demographic and obesity covariates, the proportion of variance explained by Log (ISI(0,120)) were largest among the surrogate measures in the variance-component models. Our results showed that ISI(0,120) and ISI(TX) correlated better with SSPG than those used fasting measures alone (HOMA-IR and QUICKI). Log (ISI(0,120)) currently showing the strongest association with SSPG than other estimates is adaptable for use in large studies of hypertension.

Higher frequency of dementia in older HIV-1 individuals: the Hawaii Aging with HIV-1 Cohort

BACKGROUND

Antiretroviral therapy has improved survival for HIV-1-infected individuals. The neuroepidemiologic implications of HIV-1 in an aging population are not well known, particularly the prevalence of HIV-associated dementia (HAD).

METHODS

The authors report a baseline cross-sectional analysis of 202 HIV-1-seropositive individuals enrolled into one of two groups of the Hawaii Aging with HIV Cohort: older (50 or more years old, n = 106) and younger (20 to 39 years old, n = 96). Neuropsychological, neurologic, medical, and laboratory data were obtained at enrollment. Participant cognitive status was classified (research case definitions) using American Academy of Neurology (1991) criteria in a consensus conference of physicians and neuropsychologists.

RESULTS

HAD was more frequent in older (25.2%) compared to younger (13.7%) individuals (p = 0.041) corresponding to an OR of 2.13 (95% CI: 1.02 to 4.44) for the older compared to the younger group. After adjusting for education, race, substance dependence, antiretroviral medication status, viral load, CD4 lymphocyte count, and Beck Depression Inventory score, the odds of having HAD among individuals in the older group was 3.26 (1.32 to 8.07) times that of the younger group.

CONCLUSIONS

Older age is associated with increased HAD in this HIV-1 cohort. Underlying mechanisms are unclear but do not appear related to duration of HIV-1 infection.

Age, apolipoprotein E4, and the risk of HIV dementia: the Hawaii Aging with HIV Cohort

There are discrepant findings regarding the risk of HIV-associated dementia (HAD) relating to apolipoprotein E4, suggesting other factors may modulate risk. Furthermore, evidence suggests a changing phenotype of HAD in the era of highly active antiretroviral therapy (HAART), prompting a need to determine if new disease markers have emerged. In this analysis, APOE genotype was determined for 182 participants enrolled in the Hawaii Aging with HIV Cohort. After controlling for age and diabetes status, an independent risk of HAD relating to E4 was seen in older participants [OR=2.898 (1.031-8.244)] but not in younger participants [OR=0.373 (0.054-1.581)]. Several proposed mechanisms may underlie this association. Consideration of non-traditional risk factors for HAD in older HIV patients may yield new markers of disease in the era of HAART.

Genetic epistasis of adiponectin and PPARgamma2 genotypes in modulation of insulin sensitivity: a family-based association study

AIMS/HYPOTHESIS

Genetic interactions in modulating the phenotypes of a complex trait, such as insulin sensitivity, were usually taken for granted. However, this has not been commonly shown. Previous studies have suggested that both PPARgamma2 and adiponectin genes could influence insulin sensitivity. Therefore it is likely that they could modulate insulin sensitivity through gene to gene interactions.

METHODS

We genotyped 1793 subjects of Chinese and Japanese descendents from 601 hypertensive families recruited in Sapphire study for a T94G in the adiponectin gene exon 2 and the PPARgamma2 Pro12Ala polymorphisms. Serum insulin concentrations and insulin resistance index (HOMA(IR)) were used as the markers of insulin sensitivity.

RESULTS

We found that the T allele of adiponectin gene was associated with a higher Ins60 and higher area under curve of insulin (AUCi) in OGTT utilizing all subjects in a mixed model that corrected for family effects. Important interactions between adiponectin and PPARgamma2 genotypes were found in fasting insulin concentrations (Ins0), insulin concentrations at 2-h (Ins120) in OGTT and insulin resistance index (HOMA(IR)). The main effects of the PPARgamma2 genotypes were in the plasma glucose concentrations in OGTT. In contrast, the main effects of adiponectin genotypes were in every insulin variable, including Ins0, Ins60, Ins120, AUCi and HOMA(IR). The subjects carrying the adiponectin G allele and the PPARgamma2 Ala12 allele seemed to be more insulin sensitive.

CONCLUSION/INTERPRETATION

These results showed that adiponectin is a genetic factor associated with insulin sensitivity. Interactions with PPARgamma2 genotypes modified this association.

Association of the tumour necrosis factor alpha -308 but not the interleukin 10 -627 promoter polymorphism with genetic susceptibility to primary sclerosing cholangitis

BACKGROUND AND AIMS

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown aetiology. Abnormalities in immune regulation and genetic associations suggest that PSC is an immune mediated disease. Several polymorphisms within the tumour necrosis factor alpha (TNF-alpha) and interleukin 10 (IL-10) promoter genes have been described which influence expression of these cytokines. This study examines the possible association between polymorphisms at the -308 and -627 positions in the TNF-alpha and IL-10 promoter genes, respectively, and susceptibility to PSC.

METHODS

TNF-alpha -308 genotypes were studied by polymerase chain reaction (PCR) in 160 PSC patients from Norway and the UK compared with 145 ethnically matched controls. IL-10 -627 genotypes were studied by PCR in 90 PSC patients compared with 84 ethnically matched controls.

RESULTS

A total of 16% of Norwegian PSC patients and 12% of British PSC patients were homozygous for the TNF2 allele compared with 3% and 6% of respective controls. The TNF2 allele was present in 60% of PSC patients versus 30% of controls (OR(combined data)=3.2 (95% confidence intervals (CI) 1.8--4.5); p(corr)=10(-5)). The association between the TNF2 allele and susceptibility to PSC was independent of the presence of concurrent inflammatory bowel disease (IBD) in the PSC patients; 61% of PSC patients without IBD had TNF2 compared with 30% of controls (OR(combined data)=3.2 (95% CI 1.2--9.0); p(corr)=0.006 ). There was no difference in the -627 IL-10 polymorphism distributions between patients and controls in either population. The increase in TNF2 allele in PSC patients only occurs in the presence of DRB1*0301 (DR3) and B8. In the combined population data, DRB1*0301 showed a stronger association with susceptibility to PSC than both the TNF2 and B8 alleles (OR(combined data)=3.8, p(corr)=10(-6) v OR(combined data)=3.2, p(corr)=10(-5) v OR(combined data )=3.41, p(corr)=10(-4), respectively).

CONCLUSIONS

This study identified a significant association between possession of the TNF2 allele, a G-->A substitution at position -308 in the TNF-alpha promoter, and susceptibility to PSC. This association was secondary to the association of PSC with the A1-B8-DRB1*0301-DQA1*0501-DQB1*0201 haplotype. No association was found between the IL-10 -627 promoter polymorphism and PSC.

Interleukin 10 promoter region polymorphisms and susceptibility to advanced alcoholic liver disease

BACKGROUND

The factors determining why less than 10% of heavy drinkers develop advanced alcoholic liver disease (ALD) remain elusive, although genetic factors may be important. Interleukin 10 (IL-10) is an important cytokine with anti-inflammatory, anti-immune, and antifibrotic functions. Several polymorphisms have been identified in the IL-10 promoter and recent evidence suggests that some of these may have functional effects on IL-10 secretion.

AIMS

To test the hypothesis that IL-10 promoter region polymorphisms are associated with susceptibility to ALD.

METHODS

The allele frequencies for the two single base pair substitutions at positions -627 (C-->A) and -1117 (A-->G) in the IL-10 promoter were determined in 287 heavy drinkers with biopsy proved advanced ALD, 107 heavy drinkers with no evidence of liver disease or steatosis only on biopsy, and 227 local healthy volunteers.

RESULTS

At position -627, 50% of patients with advanced ALD had a least one A allele compared with 33% of controls (p<0.0001) and 34% of drinkers with no or mild disease (p=0.017). At position -1117, the slight excess of the A allele in drinkers with advanced disease was because of linkage disequilibrium between the A alleles at the two sites.

CONCLUSIONS

Among heavy drinkers, possession of the A allele at position -627 in the IL-10 promoter is associated with an increased risk of advanced liver disease. This is consistent with recent functional data that the -627*A allele is associated with low IL-10 expression which will favour inflammatory, immune mediated, and profibrotic mechanisms of alcohol related liver injury.

Underreporting of family history of colon cancer: correlates and implications

Scientific advances in cancer genetics, risk counseling, and management of high-risk individuals require information about familial cancer history. Because some people may not report, or may be unaware of, cancer in their families, it is important to examine the extent of underreporting of family history. We mailed a survey to first-degree relatives of patients with histologically confirmed diagnoses of colorectal cancer (CRC) before age 60 (n = 426, 77% response rate). Analyses examined the extent of underreporting of family history and its predictors (demographics, cancer characteristics, knowledge, and communication) and correlates (cancer worry, perceived risk). Logistic regression analysis was performed using generalized estimating equations to account for family clusters. Despite confirmed diagnosis of CRC in a parent or sibling, 25.4% of respondents reported having no first-degree relative with colon cancer. In multivariate models, the most significant predictor of awareness of a relative's CRC was the stage-at-diagnosis; also, males and those with low knowledge about colon cancer were significantly less aware. Awareness of a relative's CRC was associated with higher cancer worry and risk perception, and being a college graduate contributed independently to increased risk perception. Sole dependence on mailed self-administered questionnaires may lead to substantial underreporting of familial colon cancers, especially those that are in situ or localized.

Correlates of intentions to obtain genetic counseling and colorectal cancer gene testing among at-risk relatives from three ethnic groups

OBJECTIVES

An understanding of factors associated with interest in genetic counseling and intentions to obtain colorectal cancer susceptibility testing is an important foundation for developing education, counseling, and genetic services and policies.

MATERIALS AND METHODS

A survey was mailed to first-degree relatives of patients diagnosed with colorectal cancer. The respondents (n = 426, 77% response rate) are siblings and adult children of Caucasian, Japanese, and Hawaiian ethnicity. Data collection was guided by a conceptual framework and included questions on demographics, family cancer history, predisposing factors (cancer worry, perceived risk, well-being), and enabling factors (decision preferences, social support, and health care factors). Logistic regression analysis on two binary dependent variables (interest in counseling and intentions to get genetic testing) was performed using Generalized Estimating Equations to account for family clusters.

RESULTS

Forty-five % of respondents were interested in genetic counseling, and 26% "definitely" intended to get genetic testing for colon cancer when available. For counseling interest, the most important predictors were education, Hawaiian ethnicity, cancer worry, and family support. Cancer worry, perceived risk, and age (older) were directly, and Japanese ethnicity was inversely, associated with testing intentions.

CONCLUSIONS

High rates of interest in cancer genetic testing are similar to those found in other studies. Ethnic differences reveal a paradox between objective population risk (higher for Japanese) and greater concerns (among Hawaiians). The substantial lack of awareness of family history warrants further research. Culturally sensitive education and counseling are needed for managing the likely high demand for personalized information about hereditary cancer risk.

Tumour necrosis factor-alpha promoter polymorphisms in primary biliary cirrhosis

BACKGROUND/AIMS

The incidence of primary biliary cirrhosis (PBC) is increased in the close relatives of patients, suggesting that genetic factors play a role in disease susceptibility. Decreased in vitro production of tumour necrosis factor (TNF)-alpha has been reported in PBC patients, suggesting a potential aetiological role for this cytokine. The aim of this study was to examine two biallelic polymorphisms in the promoter region of the TNF-alpha gene, which may play a role in the control of TNF-alpha secretion, as candidate susceptibility loci in PBC.

METHODS

The polymorphisms at positions -238 and -308 in the TNF-alpha promoter region were analysed by polymerase chain reaction in 168 unrelated PBC patients and 145 local unrelated, geographically matched normal individuals. All PBC subjects were also genotyped for HLA DR8, a previously identified susceptibility locus in PBC.

RESULTS

The -308 TNF1/TNF1 genotype was seen in a similar proportion of PBC patients (66%) and controls (60%). However, this genotype was found significantly more frequently in the 95 PBC patients with more advanced disease (histological stage III/IV) (77%) than in either controls (p<0.01, OR = 2.2 [1.2-4.0]) or the PBC patients with earlier disease (38/73 (52%), p = 0.001 OR 3.1 [1.6-5.9]). Linkage between TNF -308 and HLA DR8 was not seen. No association was found between PBC and the biallelic -238 TNF-alpha polymorphism, either in the whole PBC population or the histological Stage III/IV subgroup.

CONCLUSIONS

Our study provides no evidence for involvement of the TNF-alpha -308 or -238 promoter polymorphisms in genetic predisposition to PBC. However, the significantly increased frequency of the -308 TNF1/TNF1 genotype seen in 95 patients with more advanced disease raises the possibility that this allele may be linked to disease progression rather than susceptibility. The finding of different allele frequencies in PBC patients in different disease subgroups emphasises the importance of clinical phenotype/casemix in the design of disease association studies.

Detection and characterization of novel polymorphisms in the CYP2E1 gene

To investigate whether interindividual variation in CYP2E1 levels can be explained by genetic polymorphism, we analysed DNA samples from 40 healthy individuals by single-strand conformational polymorphism analysis for polymorphisms in the CYP2E1 coding sequence and promoter region. DNA sequencing of samples showing mobility shifts on single-strand conformational polymorphism detected polymorphisms at positions -316 (A to G), -297 (T to A), -35 (G to T), 1107 (G to C; intron 1), 4804 (G to A Val179Ile; exon 4) and 10157 (C to T; exon 8). All individuals positive for either A(-316)G, G(-35)T, G(4804)A or the previously described RsaI polymorphism at -1019 were also positive for T(-297)A, which had the highest allele frequency of the observed polymorphisms (0.20). A(-316)G, G(-35)T and G(4804)A were detected at allele frequencies of 0.022, 0.052 and 0.013, respectively. The functional significance of the upstream polymorphisms was examined by preparing constructs of positions -549 to +3 of CYP2E1 containing the observed combinations of the polymorphisms fused to luciferase reporter genes and transfecting HepG2 cells. For the G(-35)T/T(-297)A construct, a 1.8-fold increase in luciferase activity compared with the wild-type sequence (P = 0.06) and 2.5-fold compared with T(-297)A only (P = 0.025) was observed. No significant difference in activity was observed between the other constructs. The significance of the predicted Val179Ile base change from G(4804)A was determined by expression of the wild-type and mutated full length cDNAs in lymphoblastoid cells. No significant difference in kinetic constants for chlorzoxazone hydroxylation between mutant and wild-type was observed. In summary, this study demonstrated six novel CYP2E1 polymorphisms, including three upstream of the promoter, but with the possible exception of G(-35)T, none appeared to be of functional significance.

Heterozygotes for HFE mutations have no increased risk of advanced alcoholic liver disease

BACKGROUND

Iron overload is common in the livers of alcoholics and may play a role in disease pathogenesis. An MHC like gene, HFE, has recently been identified that is mutated in most patients with hereditary haemochromatosis (C282Y in 90% and H63D in 45% of the remainder).

AIM

To examine the hypothesis that these mutations determine hepatic iron status in alcoholics and play a role in pre-disposition to advanced alcoholic liver disease.

METHODS

The HFE gene was genotyped in 257 patients with alcoholic liver disease and 117 locally matched healthy volunteers. In addition, iron staining was scored (0-4) on biopsy specimens from fibrotic/cirrhotic patients with and without HFE mutations matched for age and sex.

RESULTS

Some 15.7% of fibrotic/cirrhotic patients were C282Y heterozygotes compared with 13.7% of controls (p = 0.77). One control and three patients were C282Y homozygotes. Of chromosomes without the C282Y mutation, 68/442 (15.4%) of patients' chromosomes carried the H63D mutation compared with 36/216 (16.6%) of control chromosomes (p = 0.91). Significant (> grade 1) hepatocyte iron staining was seen in 6/23 C282Y heterozygotes and 4/26 H63D heterozygotes compared with 4/23 controls.

CONCLUSIONS

Possession of a single copy of either of the two HFE mutations influences neither liver iron content nor the risk of fibrotic disease in alcoholics.

The RsaI polymorphism of CYP2E1 and susceptibility to alcoholic liver disease in Caucasians: effect on age of presentation and dependence on alcohol dehydrogenase genotype

Twin studies in Caucasians suggest that susceptibility to alcoholic liver disease is, in part, genetically determined. Because most of the deleterious effects of alcohol are caused by its metabolism, attention has focused upon genes encoding ethanol metabolizing enzymes. Caucasians are polymorphic at only two of these gene loci--cytochrome P450 2E1 (CYP2E1) and alcohol dehydrogenase 3 (ADH3). We examined the frequency of the RsaI polymorphism of CYP2E1 and ADH3 genotype in 264 patients with alcoholic liver disease and 121 local control individuals. There was a non-significant excess of the rare c2 CYP2E1 allele in patients with advanced liver disease compared with control individuals/patients with steatosis only (0.029 versus 0.017/0.00). However, patients with the c2 allele presented at a younger age compared with those with the wild type c1 allele only (42.3 +/- 1.6 years versus 49.0 +/- 0.6 years; P = 0.001) with at least as advanced histology (93% cirrhotic versus 74%). Male patients had a higher frequency of the ADH3*2/*2 genotype (which encodes the less active gamma2 subunit) than control individuals [odds ratio (OR) 2.04 (1.11-3.76)], however, ADH3 genotype did not differ with histological stage or with age of presentation. Patients with advanced disease possessing the c2 allele had a significantly higher frequency of the ADH3*2/*2 genotype compared with c1 homozygotes [OR 3.71 (1.24-11.09)]. This study demonstrates that, although rare in Caucasians, possession of the mutant c2 allele of CYP2E1 increases the risk of alcoholic liver disease at a given level of cumulative alcohol consumption. This risk appears to be particularly manifest in individuals carrying the ADH3*2 allele, presumably reflecting increased metabolism of ethanol by CYP2E1. In the absence of the c2 allele, ADH3 genotype does not influence the risk of advanced alcoholic liver disease but, in males at least, may influence the risk of alcoholism.

No evidence for involvement of the interleukin-10 -592 promoter polymorphism in genetic susceptibility to primary biliary cirrhosis

BACKGROUND/AIMS

Primary biliary cirrhosis is a chronic cholestatic liver disease with an autoimmune aetiology. Family studies, which have shown a significantly increased incidence of primary biliary cirrhosis in the close relatives of patients, suggest that genetic factors play a significant role in determining disease susceptibility. Several studies have previously identified loci which appear to play a role in determining this susceptibility, including the MHC class II allele HLA DR8, and the class III encoded C4A null allele (C4AQ0). Here, we have studied another candidate susceptibility locus in primary biliary cirrhosis, an apparently functional biallelic polymorphism at position -592 in the promoter region of the gene encoding the immuno-modulatory cytokine interleukin-10. Interleukin-10 plays an important role in the functional control, in vivo, of autoreactive Th-1 type CD4+ T-cells, with experimental manipulation of interleukin-10 leading to significant modulation of disease development in animal models of autoimmunity.

METHODS

Interleukin-10 -592 genotypes were studied by polymerase chain reaction in 171 well-characterised, histologically-staged, primary biliary cirrhosis patients and 141 locally matched controls.

RESULTS

Of 171 primary biliary cirrhosis patients, 99 were homozygous for the commoner allele (C/C), 68/171 (40%) were heterozygotes (A/C), whilst 4/171 (2%) were homozygous for the rarer allele (A/A). These genotype frequencies were not significantly different from those seen in controls (p=0.49, odds ratio 1.2 [0.8-1.91).

CONCLUSIONS

These findings, in the first study of IL-10 as a candidate locus in a human autoimmune disease, suggest that IL-10 -592 is not a susceptibility locus in primary biliary cirrhosis.

Involvement of products of the nrfEFG genes in the covalent attachment of haem c to a novel cysteine-lysine motif in the cytochrome c552 nitrite reductase from Escherichia coli

Cytochrome c552 is the terminal component of the formate-dependent nitrite reduction pathway of Escherichia coli. In addition to four 'typical' haem-binding motifs, CXXCH-, characteristic of c-type cytochromes, the N-terminal region of NrfA includes a motif, CWSCK. Peptides generated by digesting the cytochrome from wild-type bacteria with cyanogen bromide followed by trypsin were analysed by on-line HPLC MS/MS in parent scanning mode. A strong signal at mass 619, corresponding to haem, was generated by fragmentation of a peptide of mass 1312 that included the sequence CWSCK. Neither this signal nor the haem-containing peptide of mass 1312 was detected in parallel experiments with cytochrome that had been purified from a transformant unable to synthesize NrfE, NrfF and NrfG: this is consistent with our previous report that NrfE and NrfG (but not NrfF) are essential for formate-dependent nitrite reduction. Redox titrations clearly revealed the presence of high and low mid-point potential redox centres. The best fit to the experimental data is for three n=1 components with mid-point redox potentials (pH 7.0) of +45 mV (21% of the total absorbance change), -90 mV (36% of the total) and -210mV (43% of the total). Plasmids in which the lysine codon of the cysteine-lysine motif, AAA, was changed to the histidine codon CAT (to create a fifth 'typical' haem c-binding motif), or to the isoleucine and leucine codons, ATT and CTT, were unable to transform a Nrf deletion mutant to Nrf+ or to restore formate-dependent nitrite reduction to the transformants. The presence of a 50 kDa periplasmic c-type cytochrome was confirmed by staining proteins separated by SDS-PAGE for covalently bound haem, but the methyl-viologen-dependent nitrite reductase activities associated with the mutated proteins, although still detectable, were far lower than that of the native protein. The combined data establish not only that there is a haem group bound covalently to the cysteine-lysine motif of cytochrome c552 but also that one or more products of the last three genes of the nrf operon are essential for the haem ligation to this motif.

Tumour necrosis factor-alpha gene promoter polymorphism and decreased insulin resistance

Insulin resistance is a feature of non-diabetic relatives of non-insulin-dependent diabetic (NIDDM) families. Tumour necrosis factor-alpha (TNF alpha) expression is linked with insulin resistance, and is under strong genetic control. We examined the relationship between insulin resistance and two polymorphisms of the TNF alpha promoter region (positions -238 and -308). Non-diabetic relatives (n = 123) of NIDDM families and control subjects (n = 126) with no family history of diabetes were studied. Insulin resistance was determined by homeostasis model assessment (HOMA) and short insulin tolerance test (ITT), and genotyping was by restriction digest. The -238 polymorphism (TNFA-A allele) was carried by 14 relatives and 11 control subjects, and all were heterozygotes. To examine the relationship between the -238 polymorphism and insulin resistance independent of potentially confounding factors, the relatives with the TNFA-A allele were individually pair-matched for age, sex, waist-hip ratio, body mass index, and glucose tolerance with relatives homozygous for the wild-type allele. Relatives with the TNFA-A allele had decreased insulin resistance (HOMA index: 2.0, 3.6 +/- 2.1 [means +/- SD of differences], p = 0.03), and this was true for comparable pair-matched control subjects (HOMA index: 1.1, 1.9 +/- 0.8, p = 0.01). Combining relative (n = 7) and control (n = 4) pairs that had undergone an ITT, subjects with the TNFA-A allele had an increased K(ITT) (3.8, 3.0 +/- 1.0%/min, p = 0.04) similarly indicating decreased insulin resistance. There was no significant relationship between the -308 polymorphism and insulin resistance. We conclude that the TNFA-A allele is associated with decreased insulin resistance as assessed by two independent methods, and may protect against the future development of NIDDM in susceptible individuals.

Association of a tumor necrosis factor promoter polymorphism with susceptibility to alcoholic steatohepatitis

Twin concordance studies suggest that genetic factors play a role in determining why only a minority of heavy drinkers develop hepatitis and cirrhosis. Tumor necrosis factor alpha (TNF-alpha) has emerged as the "final common pathway" in the pathogenesis of alcohol-related hepatic necro-inflammation. We have examined the frequency of the two recently described polymorphisms of the TNF-alpha promoter in 150 patients with biopsy-proven alcoholic liver disease and 145 healthy volunteers. There was a significant excess of the rare allele (TNFA-A; G(-238) --> A) at position -238 in patients with steatohepatitis compared with controls or patients without this lesion. This is consistent with previous suggestions that the TNFA-A allele, which falls within a putative Y regulation box of the TNF-alpha promoter, is associated with increased TNF-alpha expression. No differences were observed for the polymorphism at position -308.

Catecholaminergic expression in 2N27 immortal neural cell line is enhanced by glial-derived factors

The goal of this study was to examine the responsiveness of an immortalized catecholaminergic neuronal line, 2N27, to various growth factors and identify those which promote catecholaminergic expression. 2N27 is a newly established neural cell line derived from fetal rat mesencephalic tissue and, thus, contains tyrosine hydroxylase (TH), a reliable marker for catecholaminergic neurons. Using TH activity as a biochemical index, we examined the responsiveness to both recognized trophic factors (NGF, TGF-beta and basic- and acidic-FGF) as well as novel, glia-derived factors present in conditioned media from several glial sources. The glial cells included MACH, a normal cell line derived from aged mouse cerebral hemispheres NBCC, normal glia derived from newborn mouse cerebral hemispheres; and C-6 glioma cells, 2B clone, passage 72, predominately astrocytes. Cells were cultured in the presence of added factors from 0 to 3 days in vitro (DIV) and were harvested on day 4. We found that 2N27 neural cells responded differentially to growth factors. No change was observed in TH activity in response to NGF, TH activity even decreased in response to b-FGF ad TGF-beta addition to the culture medium. However, a dose dependent increase in TH activity was observed following treatment with a-FGF and the increase to a-FGF was associated to an increase in cell proliferation as compared to TH increase by cAMP associated to differentiation. However, the 2N27 cells responded with a marked increase in TH when cultured in the glial cell conditioned media. We conclude that immortal cells require a variety of microenvironmental signals to maintain their phenotype.

Interaction of LS174T human colon cancer cell mucins with Entamoeba histolytica: an in vitro model for colonic disease

BACKGROUND & AIMS

Colonic mucins secreted by goblet cells protect the colon by preventing the attachment of enteric pathogens to the epithelium. Entamoeba histolytica overcomes this protective barrier and causes ulcerations, allowing the parasite to disseminate to the liver and form abscesses. An in vitro model is used to study the interaction between E. histolytica and colonic mucins.

METHODS

Secretory mucins from the colonic adenocarcinoma cell line LS174T were collected and their functions assessed by their ability to inhibit amebic adherence to target cells and killing. The cytoprotective effect of mucus against E. histolytica cytolysis of LS174T monolayers was studied at 37 degrees C.

RESULTS

Sepharose 4B column chromatography, metabolic labeling with [3H]glucosamine, cesium chloride density gradient centrifugation, and amino acid and carbohydrate compositional analysis revealed that LS174T cell mucins were typical of native colonic mucins. Mucin O-linked oligosaccharides bound to and inhibited the adherence of amebae to Chinese hamster ovary cells. E. histolytica killing of Chinese hamster ovary cell monolayers occurred rapidly, whereas killing of LS174T monolayers with an intact mucus layer was significantly retarded.

CONCLUSIONS

Our results show that colonic mucins serve as the first line of host defense against amebic invasion and provide a useful model to study pathogen-mucin interactions.

Escherichia coli K-12 genes essential for the synthesis of c-type cytochromes and a third nitrate reductase located in the periplasm

The 'aeg46.5' operon was originally detected as an 'anaerobically expressed gene' located at minute 46.5 on the Escherichia coli linkage map. Subsequent results from the E. coli Genome Sequencing Project revealed that the 'aeg46.5' promoter was located in the centisome 49 (minute 47) region. Downstream from this promoter are 15 genes, seven of which are predicted to encode a periplasmic nitrate reductase and eight encode proteins homologous to proteins essential for cytochrome c assembly in other bacteria. All of these genes, together with the 'aeg46.5' promoter, have been subcloned on a 20kb EcoRI fragment from Kohara phage 19D1. Evidence is presented that, as predicted, the region includes structural genes for two c-type cytochromes of mass 16kDa and 24 kDa, which are transcribed from the previously described 'aeg46.5' promoter, and that the first seven genes encode a functional nitrate reductase. We, therefore, propose that they should be designated nap (nitrate reductase in the periplasm) genes. Plasmids encoding the entire 20kb region, or only the downstream eight genes, complemented five mutations resulting in total absence of all five known c-type cytochromes in E coli, providing biochemical evidence that these are ccm (for cytochrome c maturation) genes. The ccm region was transcribed both from the FNR-dependent, NarL- and NarP-regulated nap promoter (formerly the 'aeg46.5' promoter) and from constitutive or weakly regulated promoters apparently located within the downstream nap and ccm genes.

Plasticity of astrocytes derived from aged mouse cerebral hemispheres: changes with cell passage and immortalization

This study was targeted at the beginning to understand the functional status of glial cells derived from aged brain. We have previously characterized passaged cell cultures derived from aged mouse cerebral hemispheres (MACH) and found them to contain large populations of astrocytes, type 1, as well as limited numbers of astrocytes, type 2, oligodendrocytes, and progenitor cells. Using the activity of the astrocyte marker, glutamine synthetase (GS), as an index, we found that MACH astrocytes continue to respond to several microenvironmental signals, including the cAMP-enhancing agents dibutyryl cAMP and R020-1724 (an inhibitor of phosphodiesterase). In addition, whereas the basal activity of GS increased with cell passage, their response to these agents was cell-passage dependent, increasing at early (21-22) passages and decreasing at later (46-51) passages. Because neurotrophins (i.e., NGF and EGF) also provide microenvironmental signals essential to normal glial function, MACH cultures were assessed for their response to these factors. MACH cultures at passage 35 responded to treatment with NGF and EGF with a dose-dependent increase in GS activity by both neurotrophins. With the intention of arresting these cultures at a specific stage of differentiation, these cells were immortalized at passage 19 by transfection with the gene encoding SV40 Large T antigen. These immortalized MACH responded to exposure to dBcAMP and RO20-1724 with a marked decrease in GS activity, mimicking the response of normal MACH glia at late passage. Finally, because it has been shown that glia from both immature and adult brain contain neurotrophins and respond to neurotrophins via a receptor-mediated pathway, we examined expression of NGF protein as well as NGF (p75) and EGF receptor protein in various passages and colonies of normal and immortalized MACH cultures. We found a consistent expression of all three proteins in the various cell populations. Results of this study suggest that astrocytes from aging brain continue to function normally with respect to several parameters (i.e., response to neurotrophins and differentiating agents). Thus, they retain their plasticity to a great degree through early cell passages. However, with advancing cell passage this plasticity declines and cell homeostasis is impaired. We propose, therefore, that astrocytes undergo several critical periods in their functional lifespan, one of which is represented by the functional transition demonstrated in this study.