Novel pharmacogenetic markers for treatment outcome in azathioprine-treated inflammatory bowel disease

BACKGROUND

Azathioprine (AZA) pharmacogenetics are complex and much studied. Genetic polymorphism in TPMT is known to influence treatment outcome. Xanthine oxidase/dehydrogenase (XDH) and aldehyde oxidase (AO) compete with TPMT to inactivate AZA.

AIM

To assess whether genetic polymorphism in AOX1, XDH and MOCOS (the product of which activates the essential cofactor for AO and XDH) is associated with AZA treatment outcome in IBD.

METHODS

Real-time PCR was conducted for a panel of single nucleotide polymorphism (SNPs) in AOX1, XDH and MOCOS using TaqMan SNP genotyping assays in a prospective cohort of 192 patients receiving AZA for IBD.

RESULTS

Single nucleotide polymorphism AOX1 c.3404A > G (Asn1135Ser, rs55754655) predicted lack of AZA response (P = 0.035, OR 2.54, 95%CI 1.06-6.13) and when combined with TPMT activity, this information allowed stratification of a patient's chance of AZA response, ranging from 86% in patients where both markers were favourable to 33% where they were unfavourable (P < 0.0001). We also demonstrated a weak protective effect against adverse drug reactions (ADRs) from SNPs XDH c.837C > T (P = 0.048, OR 0.23, 95% CI 0.05-1.05) and MOCOS c.2107A > C, (P = 0.058 in recessive model, OR 0.64, 95%CI 0.36-1.15), which was stronger where they coincided (P = 0.019).

CONCLUSION

These findings have important implications for clinical practice and our understanding of AZA metabolism.

Predicting ischaemic stroke subtype from presenting systolic blood pressure: the BASIC Project

OBJECTIVE

We hypothesized that low presenting systolic blood pressure (SBP) predicted cardioembolic stroke aetiology.

DESIGN

Active and passive surveillance were used to identify all ischaemic strokes as part of the Brain Attack Surveillance in Corpus Christi (BASIC) population-based study. Multinomial logistic regression was used to examine the association between stroke subtype and first documented SBP in the medical record.

SETTING

Nueces County, TX, USA (313,645 residents in 2000). The community is urban with the majority of the population residing in the city of Corpus Christi. The area is served by seven adult acute care hospitals.

PATIENTS

Three hundred and eight cases with completed ischaemic stroke and determined subtype aetiology between January 2000 and December 2002.

RESULTS

Lower presenting SBP was associated with stroke subtype (P = 0.001). This association remained significant in the final model adjusted for age and history of coronary artery disease. The odds of cardioembolic versus small vessel occlusion increased by 20% (OR = 1.20, 95% CI: 1.07-1.35) for every 10 mmHg decrease in presenting SBP. Other covariates including race/ethnicity, gender, history of hypertension, and diabetes were neither significant predictors of stroke subtype, nor did they confound the association of SBP and stroke subtype. A 5 year increase in age increased the odds of cardioembolic subtype by 25% (OR = 1.25, 95% CI: 1.07-1.47).

CONCLUSIONS

Lower initial SBP and older age at ischaemic stroke presentation were associated with cardioembolic stroke. Suspicion of cardioembolic stroke should be increased in those presenting with low SBP.

Oxidative stress signaling in Alzheimer's disease

Multiple lines of evidence demonstrate that oxidative stress is an early event in Alzheimer's disease (AD), occurring prior to cytopathology, and therefore may play a key pathogenic role in AD. Oxidative stress not only temporally precedes the pathological lesions of the disease but also activates cell signaling pathways, which, in turn, contribute to lesion formation and, at the same time, provoke cellular responses such as compensatory upregulation of antioxidant enzymes found in vulnerable neurons in AD. In this review, we provide an overview of the evidence of oxidative stress and compensatory responses that occur in AD, particularly focused on potential sources of oxidative stress and the roles and mechanism of activation of stress-activated protein kinase pathways.

Genotypic Approaches to Therapy in Children (GATC): using information technology to improve drug safety

Adverse drug reactions (ADRs) are a major cause of morbidity and mortality in children. Current models of ADR surveillance have repeatedly demonstrated little pragmatic value to practicing clinicians. ADR reporting rates in the US and Canada suggest that only 5% of ADRs are reported. The Genotypic Approaches to Therapy in Children (GATC) network was established to identify and solve drug safety problems in paediatrics. We hypothesized that genetic polymorphisms underlie a significant portion of concentration-dependent ADRs in children. Our objective was to establish an ADR active surveillance network in paediatric hospitals across Canada. Surveillance clinicians evaluate clinical information from ADR cases and drug-matched controls, and collected DNA samples from all patients. The surveillance network will enable the identification of predictive genomic-markers for ADRs. With this knowledge, children at risk can be identified before therapy is initiated and enable personalized adjustments to therapy based on genetic make-up.

5-HT inhibition of rat insulin 2 promoter Cre recombinase transgene and proopiomelanocortin neuron excitability in the mouse arcuate nucleus

A number of anti-obesity agents have been developed that enhance hypothalamic 5-HT transmission. Various studies have demonstrated that arcuate neurons, which express proopiomelanocortin peptides (POMC neurons), and neuropeptide Y with agouti-related protein (NPY/AgRP) neurons, are components of the hypothalamic circuits responsible for energy homeostasis. An additional arcuate neuron population, rat insulin 2 promoter Cre recombinase transgene (RIPCre) neurons, has recently been implicated in hypothalamic melanocortin circuits involved in energy balance. It is currently unclear how 5-HT modifies neuron excitability in these local arcuate neuronal circuits. We show that 5-HT alters the excitability of the majority of mouse arcuate RIPCre neurons, by either hyperpolarization and inhibition or depolarization and excitation. RIPCre neurons sensitive to 5-HT, predominantly exhibit hyperpolarization and pharmacological studies indicate that inhibition of neuronal firing is likely to be through 5-HT_1F receptors increasing current through a voltage-dependent potassium conductance. Indeed, 5-HT_1F receptor immunoreactivity co-localizes with RIPCre green fluorescent protein expression. A minority population of POMC neurons also respond to 5-HT by hyperpolarization, and this appears to be mediated by the same receptor-channel mechanism. As neither POMC nor RIPCre neuronal populations display a common electrical response to 5-HT, this may indicate that sub-divisions of POMC and RIPCre neurons exist, perhaps serving different outputs.

Gender and ethnic differences in subarachnoid hemorrhage

BACKGROUND

Mexican Americans (MAs) comprise the largest component of the largest minority group within the United States. The purpose of this study was to examine ethnic and gender differences in the epidemiology, presentation, and outcomes after subarachnoid hemorrhage (SAH) in a representative United States community. Targeted public health interventions are dependent on accurate assessments of groups at highest disease risk.

METHODS

All patients with nontraumatic SAH older than 44 years were prospectively identified from January 1, 2000, to December 31, 2006, as part of the Brain Attack Surveillance In Corpus Christi project, an urban population-based study in southeast Texas. Risk ratios for cumulative SAH incidence comparing MAs with non Hispanic whites (NHWs) and women with men were calculated. Descriptive statistics for other clinical and demographic variables were computed overall, by gender, and by ethnicity.

RESULTS

A total of 107 patients had a SAH during the time period (7-year cumulative incidence: 11/10,000); of these, 43 were NHW (40% of cases vs 53% of the population) and 64 were MA (60% of cases vs 48% of the population). The overall age-adjusted risk ratio for SAH in MAs compared with NHWs was 1.67 (95% CI: 1.13, 2.47), and in women compared to men was 1.74 (95% CI 1.16, 2.62). Overall in-hospital mortality was 32.2%. No ethnic difference was observed for discharge disability or in-hospital mortality.

CONCLUSIONS

Subarachnoid hemorrhage disproportionately affects Mexican Americans and women. Public health interventions should target these groups to reduce the impact of this severe disease.

Neuronal death and survival under oxidative stress in Alzheimer and Parkinson diseases

Neuronal death is a common feature in neurodegenerative diseases including Alzheimer disease (AD) and Parkinson disease (PD). This occurs over years, not the minutes of classically defined apoptosis, and neurons show both responses of apoptosis and regeneration, evidenced by accumulated oxidative insult and attempts at cell cycle re-entry. There is recent evidence suggesting that several known gene mutations in causing familial AD (amyloid beta protein precursor, presenilin-1, or presenilin-2 gene) and familial PD (Parkin, PINK-1, or DJ-1 gene) are associated with increased oxidative stress. Also, several known genetic (e.g. Apolipoprotein Eepsilon4 variant) and environmental (e.g. metals or pesticides exposure) risk factors of sporadic AD and/or PD are associated with increased oxidative stress. In concord, patients at the preclinical stages of AD and PD as well as cellular and animal models of the diseases provide consistent evidence that oxidative insult is a significant early event in the pathological cascade of AD and PD. In contrast to the general aspects of the pathological hallmarks, aggregation of the disease-specific proteins such as amyloid-beta, tau, and alpha-synuclein may act as a compensatory (survival) response against the oxidative insult via the mechanism that the disease-specific structures sequester redox-active metals. Expanding knowledge of the molecular mechanisms of organism longevity indicates that pro-longevity gene products such as forkhead transcription factors and sirtuins are involved in the insulin-like signaling pathway and oxidative stress resistance against aging. An enhancement of the pro-longevity signaling (e.g. caloric restriction) may be a promising approach as anti-oxidative strategy against age-associated neurodegenerative diseases.

Rate measurements of the hydrolysis of complex organic macromolecules in cold aqueous solutions: implications for prebiotic chemistry on the early Earth and Titan

Organic macromolecules ("complex tholins") were synthesized from a 0.95 N(2)/0.05 CH(4) atmosphere in a high-voltage AC flow discharge reactor. When placed in liquid water, specific water soluble compounds in the macromolecules demonstrated Arrhenius type first order kinetics between 273 and 313 K and produced oxygenated organic species with activation energies in the range of approximately 60+/-10 kJ mol(-1). These reactions displayed half lives between 0.3 and 17 days at 273 K. Oxygen incorporation into such materials--a necessary step toward the formation of biological molecules--is therefore fast compared to processes that occur on geologic timescales, which include the freezing of impact melt pools and possible cryovolcanic sites on Saturn's organic-rich moon Titan.

Oxidative RNA damage and neurodegeneration

Although cellular RNA should be subject to the same oxidative insults as DNA and other cellular macromolecules, oxidative damage to RNA has not been a major focus in investigating the magnitude and the biological consequences of the free radical damage. However, because RNA is mostly single-stranded and its bases are not protected by hydrogen bonding and are less protected by specific proteins, RNA may be more susceptible to oxidative insults than DNA. Thereafter, oxidative damage to protein-coding RNA or non-coding RNA will potentially cause errors in proteins or dysregulation of gene expression. While less lethal than mutations in genome, such non-acutely lethal insults to cells might be associated with underlying mechanisms of several human diseases, especially chronic degeneration. Recently, oxidative RNA damage has been described in several neurodegenerative diseases including Alzheimer disease, Parkinson disease, dementia with Lewy bodies, and prion diseases. Of particular interest, oxidative RNA damage is a feature in vulnerable neurons at the very earliest-stages of these diseases, suggesting that RNA oxidation may actively contribute to the onset or to the development of disease. Mechanistically speaking, an increasing body of evidence suggests that the detrimental effects of oxidative RNA damage to protein synthesis are attenuated, at least in part, by the existence of mechanisms that avoid the incorporation of the damaged ribonucleotides into the translational machinery. Further investigations toward understanding of the consequences and processing mechanisms related to oxidative RNA damage may provide significant insights into the pathogenesis and therapeutic strategies for neurodegenerative and other degenerative diseases.

Integrin regulation of cytoplasmic calcium in excitatory neurons depends upon glutamate receptors and release from intracellular stores

Integrins regulate cytoplasmic calcium levels ([Ca(2+)]i) in various cell types but information on activities in neurons is limited. The issue is of current interest because of the evidence that both integrins and changes in [Ca(2+)]i are required for Long-Term Potentiation. Accordingly, the present studies evaluated integrin ligand effects in cortical neurons. Integrin ligands or alpha5beta1 integrin activating antisera rapidly increased [Ca(2+)]i with effects greater in glutamatergic than GABAergic neurons, absent in astroglia, and blocked by beta1 integrin neutralizing antisera and the tyrosine kinase antagonist genistein. Increases depended upon extracellular calcium and intracellular store release. Ligand-induced effects were reduced by voltage-sensitive calcium channel and NMDA receptor antagonists, but blocked by tetrodotoxin or AMPA receptor antagonists. These results indicate that integrin ligation triggers AMPA receptor/depolarization-dependent calcium influx followed by intracellular store release and suggest the possibility that integrin modulation of activity-induced changes in [Ca(2+)]i contributes importantly to lasting synaptic plasticity in forebrain neurons.

Neuronal binucleation in Alzheimer disease hippocampus

AIMS

The literature and teachings instruct that neurones in the adult brain are fully differentiated, quiescent cells that never divide. Somewhat surprisingly, and counter to such dogma, susceptible neurones in Alzheimer disease display an activated cell cycle phenotype. However, whether this leads to a coordinated procession through the cell cycle is unclear, particularly whether neurones enter anaphase and beyond. To begin to address this issue, in this study we sought to determine whether nuclear division occurs in these neurones.

METHODS

We examined a series of 101 archived, routinely stained hippocampal sections collected at post mortem for neuropathological evaluation for evidence of neuronal binucleation.

RESULTS

We report for the first time, binucleated neurones within the hippocampus in cases of Alzheimer disease but not in control cases (P < 0.05).

CONCLUSIONS

While a relatively rare event, occurring once every 20,000 neurones, this morphological evidence that neuronal cells within the cortical regions of the adult human brain in Alzheimer disease contain two nuclei supports the hypothesis that neuronal cells can re-enter into a coordinated cell cycle that culminates in nuclear division.

Conformational changes and cleavage of tau in Pick bodies parallel the early processing of tau found in Alzheimer pathology

Neuronal protein inclusions are a common feature in Alzheimer disease (AD) and Pick disease. Even though the inclusions are morphologically different, flame-shape structure for AD vs. spherical structure for Pick disease, both have filaments mainly composed of tau protein. In AD, a well-defined pattern of conformational changes and truncation has been described. In this study, we used laser scanning confocal microscopy to characterize and compare the processing of tau protein during Pick disease with that found in AD. We found that tau protein of Pick disease preserves most of the relevant epitopes found in AD, the conformational foldings labelled by Alz-50 and Tau-66, the cleavage sites D(421) and E(391), as well as many phosphorylated sites, such as Ser(199/202), Thr(205) and Ser(396/404). We found a strong pattern of association between phosphorylation and cleavage at site D(421), as well as the phosphorylation and the conformational Alz-50 epitope. When we used late AD markers such as the conformational Tau-66 epitope and MN423 (cleavage at site E(391)) in Pick bodies (PBs), the overlap was significantly less. Furthermore, following morphological quantification, we found significantly higher numbers of phosphorylated tau in PBs. Overall, our findings suggest that phosphorylation is an early event, likely preceding the cleavage of tau at D(421). Despite this consistency with AD, we found a major distinction, namely that PBs lack beta-sheet conformation. We propose a scheme of early tau processing in these structures, similar to neurofibrillary tangles of AD.

Mutant ubiquitin found in Alzheimer's disease causes neuritic beading of mitochondria in association with neuronal degeneration

A dinucleotide deletion in human ubiquitin (Ub) B messenger RNA leads to formation of polyubiquitin (UbB)+1, which has been implicated in neuronal cell death in Alzheimer's and other neurodegenerative diseases. Previous studies demonstrate that UbB+1 protein causes proteasome dysfunction. However, the molecular mechanism of UbB+1-mediated neuronal degeneration remains unknown. We now report that UbB+1 causes neuritic beading, impairment of mitochondrial movements, mitochondrial stress and neuronal degeneration in primary neurons. Transfection of UbB+1 induced a buildup of mitochondria in neurites and dysregulation of mitochondrial motor proteins, in particular, through detachment of P74, the dynein intermediate chain, from mitochondria and decreased mitochondria-microtubule interactions. Altered distribution of mitochondria was associated with activation of both the mitochondrial stress and p53 cell death pathways. These results support the hypothesis that neuritic clogging of mitochondria by UbB+1 triggers a cascade of events characterized by local activation of mitochondrial stress followed by global cell death. Furthermore, UbB+1 small interfering RNA efficiently blocked expression of UbB+1 protein, attenuated neuritic beading and preserved cellular morphology, suggesting a potential neuroprotective strategy for certain neurodegenerative disorders.

Early care limitations independently predict mortality after intracerebral hemorrhage

OBJECTIVE

Intracerebral hemorrhage (ICH) is associated with a high early mortality rate. We examined the impact of early do not resuscitate (DNR) orders and other limitations in aggressive care on mortality after ICH in a community-based study.

METHODS

Cases of spontaneous ICH from 2000 to 2003 were identified from the Brain Attack Surveillance in Corpus Christi (BASIC) project, with deaths ascertained through 2005. Charts were reviewed for early (<24 hours from presentation) DNR orders, withdrawal of care, or deferral of other life sustaining interventions, analyzed together as combined DNR (C-DNR). Multivariable Cox-proportional hazards models were used to examine the association between short- and long-term all-cause mortality and early C-DNR, adjusted for demographics and established predictors of mortality after ICH.

RESULTS

Of 18,393 subjects screened for cerebrovascular disease, 270 non-traumatic ICH cases were included. Cumulative mortality risk was 0.43 at 30 days and 0.55 over the study course. Early C-DNR was noted in 34% of cases and was associated with a doubling in the hazard of death both at 30 days (hazard ratio [HR] 2.17, 95% CI 1.38, 3.41) and at end of follow-up (HR 1.92, 95% CI 1.29, 2.87) despite adjustment for age, gender, ethnicity, Glasgow Coma Scale, ICH volume, intraventricular hemorrhage, and infratentorial hemorrhage.

CONCLUSIONS

Early care limitations are independently associated with both short- and long-term all-cause mortality after intracerebral hemorrhage (ICH) despite adjustment for expected predictors of ICH mortality. Physicians should carefully consider the effect of early limitations in aggressive care to avoid limiting care for patients who may survive their acute illness.

Dose-response of Listeria monocytogenes after oral exposure in pregnant guinea pigs

Listeriosis, a severe disease that results from exposure to the foodborne pathogen Listeria monocytogenes, is responsible for approximately 2500 illnesses and 500 deaths in the United States each year. Pregnant women are 20 times more likely to develop listeriosis than the general population, with adverse pregnancy outcomes that include spontaneous abortions, stillbirths, and neonatal meningitis. The objective of this study was to determine an infective dose that resulted in stillbirths and infectivity of selected tissues in pregnant guinea pigs. Pregnant guinea pigs were exposed orally on gestation day 35 to 10(4) to 10(8) L. monocytogenes CFU in sterile whipping cream. L. monocytogenes was recovered at 64, 73, 90, and 100% from the livers of animals infected with 10(5), 10(6), 10(7), and 10(8) CFU, respectively. In dams exposed to > or =10(6) CFU, L. monocytogenes was cultured from 50% of the spleen samples and 33% of the gallbladder samples. Eleven of 34 dams infected with > or =10(6) CFU delivered stillborn pups. L. monocytogenes was cultured from the placenta, liver, and brain tissue of all stillbirths. Dams that delivered nonviable fetuses after treatment with > or =10(7) L. monocytogenes CFU had fecal samples positive for L. monocytogenes at every collection posttreatment. On the basis of a log-logistic model, the dose that adversely affected 50% of the pregnancies was approximately 10(7) L. monocytogenes CFU compared with that estimated from a human outbreak of 106 CFU. Listeriosis in pregnant guinea pigs can result in stillbirths, and the overall disease is similar to that described in nonhuman primates and in humans.

The effect of experience on detectability in local area anatomical noise

The aim of this study was to investigate if the ability to detect clinically relevant signals, within local area clinically relevant texture, is related to experience. A two alternative forced choice interleaved staircase experiment was conducted on 101 observers split into three groups; group 1 with diagnostic experience, group 2 with experience of imaging but not of making a diagnosis and group 3 with no experience of imaging. Thresholds of detection within synthesized, clinically representative textures were measured for a 15 mm simulated lesion within an MR T1 weighted brain texture and a 2.5 mm diameter simulated lesion embedded within X-ray trabecular bone texture. The results showed that there was a significant difference in threshold detectability between the groups for the brain texture at the 95% significance level but not for the bone texture. The experienced group did not demonstrate a correlation between their bone and brain results. However, the inexperienced group had a significant correlation between the bone and brain results. There was a significant correlation between increasing experience and detectability but this was dependent on the composition of the local area anatomical noise.

Neighborhood environment and risk of ischemic stroke: the brain attack surveillance in Corpus Christi (BASIC) Project

The authors explored whether neighborhood-level characteristics are associated with ischemic stroke and whether the association differs by ethnicity, age, and gender. Using data from the Brain Attack Surveillance in Corpus Christi Project (January 2000-June 2003), they identified cases of ischemic stroke (n = 1,247) from both hospital and out-of-hospital sources. Census tracts served as proxies for neighborhoods, and neighborhood socioeconomic status scores were constructed from census variables (higher scores represented less disadvantage). In Poisson regression analyses comparing the 90th percentile of neighborhood score with the 10th, the relative risk of stroke was 0.49 (95% confidence interval (CI): 0.41, 0.58). After adjustment for age, gender, and ethnicity, this association was attenuated (relative risk (RR) = 0.79, 95% CI: 0.63, 1.00). There was no ethnic difference in the association of score with stroke (p for interaction = 0.79). Significant effect modification was found for age (p for interaction < 0.001) and gender (p for interaction = 0.04), with increasing scores being protective against stroke in men and younger persons. Associations were attenuated after adjustment for education (men: RR = 0.77, 95% CI: 0.55, 1.07; persons aged <65 years: RR = 0.65, 95% CI: 0.41, 1.02). Neighborhood characteristics may influence stroke risk in certain gender and age groups. Mechanisms for these associations should be examined.

Projected costs of ischemic stroke in the United States

BACKGROUND

There are barriers to acute stroke care in minority groups as well as a higher incidence of ischemic stroke when compared with non-Hispanic whites.

OBJECTIVE

To estimate the future economic burden of stroke in non-Hispanic whites, Hispanics, and African Americans in the United States from 2005 to 2050.

METHODS

We used U.S. Census estimates of the race-ethnic group populations age 45 years and older. We obtained stroke epidemiology and service utilization data from the Northern Manhattan Stroke Study and the Brain Attack Surveillance in Corpus Christi project and other published data. We estimated costs directly from Medicare reimbursement or from studies that used Medicare reimbursement. Direct and indirect costs considered included ambulance services, initial hospitalization, rehabilitation, nursing home costs, outpatient clinic visits, drugs, informal caregiving, and potential lost earnings.

RESULTS

The total cost of stroke from 2005 to 2050, in 2005 dollars, is projected to be 1.52 trillion dollars for non-Hispanic whites, 313 billion dollars for Hispanics, and 379 billion dollars for African Americans. The per capita cost of stroke estimates are highest in African Americans (25,782 dollars), followed by Hispanics (17,201 dollars), and non-Hispanic whites (15,597 dollars). Loss of earnings is expected to be the highest cost contributor in each race-ethnic group.

CONCLUSIONS

The economic burden of stroke in African Americans and Hispanics will be enormous over the next several decades. Further efforts to improve stroke prevention and treatment in these high stroke risk groups are necessary.

Overprescribing of lipid lowering agents

BACKGROUND

Undertreatment of hyperlipidemia has received considerable attention. However, little is known about trends in overprescribing of lipid lowering agents. We examined these trends and their associations with physician, practice, and organisational factors.

METHODS

2034 physicians were surveyed twice: baseline (1996-7) and follow up (1998-9). On each occasion they were asked: "For what percentage of 50 year old men without other cardiac risk factors would you recommend an oral agent for total cholesterol of 240, LDL 150, and HDL 50 after 6 months on a low cholesterol diet?" During the survey period the National Cholesterol Education Program guidelines did not recommend prescribing for these patients. Binomial and multinomial logistic regressions assessed baseline overprescribing and longitudinal changes in overprescribing, accounting for complex sampling.

RESULTS

39% of physicians recommended prescribing at baseline (round 1), increasing at follow up (round 2) to 51% (p < 0.001). Physicians who were more likely to overprescribe at baseline were less likely to be board certified (odds ratio (OR) 0.49, 95% confidence interval (CI) 0.38 to 0.63; p < 0.001), were in solo or two-physician practices (OR 1.88, 95% CI 1.46 to 2.41; p < 0.001), had more revenue from Medicare (OR 1.10, 95% CI 1.03 to 1.17; p = 0.004) or Medicaid (OR 1.09, 95% CI 1.01 to 1.18; p = 0.03), or were family physicians (OR 1.87, 95% CI 1.35 to 2.58; p < 0.001). Physicians with large increases in overprescibing were more likely than those with small increases in overprescribing to be international medical graduates (OR 2.09, 95% CI 1.20 to 3.64; p = 0.011) and to spend more hours in patient care (OR 1.14, 95% CI 1.03 to 1.26; p = 0.016).

CONCLUSIONS

Overprescribing of lipid lowering agents is commonplace and increased. At baseline and longitudinally, overprescribing was primarily associated with physician and practice characteristics and not with organisational factors.

Fumonisin production and bioavailability to maize seedlings grown from seeds inoculated with Fusarium verticillioides and grown in natural soils

The fungus Fusarium verticillioides infects maize and produces fumonisins. The purpose of this study was to determine the ability of F. verticillioides to produce fumonisins in synthetic and natural soils and their biological availability to maize roots. Maize seeds were inoculated with a pathogenic strain of F. verticillioides (MRC826) and planted in synthetic and three different natural soils. There were statistically significant reductions in stalk weight and root mass and increased leaf lesions in the MRC826-treated seedlings in all soil types. Fumonisins were detected in all of the soils of seedlings grown from MRC826-inoculated seeds. The fumonisin produced in the soils was biologically available to seedlings as demonstrated by the statistically significant elevation of free sphingoid bases and sphingoid base 1-phosphates in their roots. These results indicate that F. verticillioides produced fumonisins in the autoclaved synthetic and natural soils and that the fumonisin produced is biologically available on the basis of evidence of inhibition of ceramide synthase.

Trace copper levels in the drinking water, but not zinc or aluminum influence CNS Alzheimer-like pathology

Mounting evidence suggests copper may influence the progression of Alzheimer's disease by reducing clearance of the amyloid beta protein (Abeta) from the brain. Previous experiments show that addition of only 0.12 PPM copper (one-tenth the Environmental Protection Agency Human consumption limits) to distilled water was sufficient to precipitate the accumulation of Abeta in the brains of cholesterol-fed rabbits (1). Here we report that addition of copper to the drinking water of spontaneously hypercholesterolemic Watanabe rabbits, cholesterol-fed beagles and rabbits, PS1/APP transgenic mice produced significantly enhanced brain levels of Abeta. In contrast to the effects of copper, we found that aluminum- or zinc-ion-supplemented distilled water did not have a significant effect on brain Ab accumulation in cholesterol-fed rabbits. We also report that administration of distilled water produced a reduction in the expected accumulation of Ab in three separate animal models. Collectively, these data suggest that water quality may have a significant influence on disease progression and Ab neuropathology in AD.

Ultrastructural analysis of a murine model of congenital hydrocephalus produced by overexpression of transforming growth factor-beta1 in the central nervous system

The purpose of this study was to elucidate using transmission electron microscopy (TEM) the ultrastructural changes that occur within the cortical gray matter of a novel reproducible model of congenital hydrocephalus in mice created to overexpress the cytokine transforming growth factor-beta1 (TGF-beta1) in the central nervous system. Brain tissue was obtained from mice from a colony engineered to overexpress TGF-beta1 at two days postpartum and compared to a wild-type aged-matched control. This tissue was fixed using a solution containing 1.25% paraformaldehyde and 1.25% glutaraldehyde in phosphate buffer at least 3-4 h and then cut into 40-50 microm sections. Randomly selected thin sections were stained with uranyl acetate and lead citrate, and then analyzed using a JEOL-100CX or 1200EX transmission electron microscope at accelerating voltage 80 kV. Dramatic neuronal and glial pathology was observed throughout the cortical neuropil in TGF-beta1 mice. The most striking change in the hydrocephalic mice was severe edema with extracellular fluid, possibly due to cerebrospinal fluid (CSF) penetration into the cortex. In addition, severe disruption of the cytoplasmic matrix was seen throughout the cortex, with damage to cellular organelles and particularly severe damage to mitochondria. Our results suggest that congenital hydrocephalus may be associated with significant damage to cortical tissue.