Extensive DNA methylation in normal colorectal mucosa in hyperplastic polyposis

BACKGROUND

Hyperplastic polyposis of the colorectum is a precancerous condition that has been linked with DNA methylation. The polyps in this condition have been distinguished from typical small hyperplastic polyps and renamed sessile serrated adenomas. Sessile serrated adenomas also occur sporadically and appear to be indistinguishable from their counterparts in hyperplastic polyposis.

AIMS AND METHODS

The existence of distinguishing molecular features was explored in a series of serrated polyps and matched normal mucosa from patients with and without hyperplastic polyposis by assessing mutation of BRAF, DNA methylation in 14 markers (MINTs 1, 2 and 31, p16, MGMT, MLH1, RASSF1, RASSF2, NORE1 (RASSF5), RKIP, MST1, DAPK, FAS, and CHFR), and immunoexpression of MLH1.

RESULTS

There was more extensive methylation in sessile serrated adenomas from subjects with hyperplastic polyposis (p<0.0001). A more clearcut difference in patients with hyperplastic polyposis was the finding of extensive DNA methylation in normal mucosa from the proximal colon.

CONCLUSIONS

A genetic predisposition may underlie at least some forms of hyperplastic polyposis in which the earliest manifestation may be hypermethylation of multiple gene promoters in normal colorectal mucosa. Additionally, some of the heterogeneity within hyperplastic polyposis may be explained by different propensities for MLH1 inactivation within polyps.

Advanced colorectal polyps with the molecular and morphological features of serrated polyps and adenomas: concept of a 'fusion' pathway to colorectal cancer

AIM

To establish and explain the pattern of molecular signatures across colorectal polyps.

METHODS AND RESULTS

Thirty-two sessile serrated adenomas (SSA), 10 mixed polyps (MP), 15 traditional serrated adenomas (SA), 49 hyperplastic polyps (HP) and 84 adenomas were assessed for mutation of KRAS and BRAF and aberrant expression of p53. The findings were correlated with loss of expression of O-6-methylguanine DNA methyltransferase (MGMT). KRAS mutation occurred more frequently (26.5%) than BRAF mutation (4.8%) in adenomas (P < 0.001) and particularly in adenomas with villous architecture (50%). Loss of expression of MGMT correlated with KRAS mutation in small tubular adenomas (P < 0.04). BRAF mutation was frequent in HPs (67%) and SSAs (81%), while KRAS mutation was infrequent (4% and 3%, respectively). Of MPs and SAs, 72% had either BRAF or KRAS mutation. Aberrant expression of p53 was uncommon overall, but occurred more frequently in MPs and SAs (12%) than adenomas (1%) (P < 0.04) and there was concordant loss of expression of MGMT.

CONCLUSIONS

Molecular alterations that are characteristic of the serrated pathway and adenoma-carcinoma sequence can co-occur in a minority of advanced colorectal polyps that then show morphological features of both pathways. These lesions account for only 2% of colorectal polyps, but may be relatively aggressive.

Absence of previously reported variants in the SCNA (G88C and G209A), NR4A2 (T291D and T245G) and the DJ-1 (T497C) genes in familial Parkinson's disease from the GenePD study

Parkinson's disease (PD) is a neurodegenerative disorder in which relatives of the probands are affected approximately 4 times as frequently as relatives of control subjects. Several genes have been implicated as genetic risk factors for PD. We investigated the presence of six reported genetic variations in the SCNA, NR4A2, and DJ-1 genes in 292 cases of familial Parkinson's disease from the GenePD study. None of the variants were found in the GenePD families. Our results suggest that other variants or genes account for the familial risk of PD within the GenePD study.

Red cell pyruvate kinase deficiency: 17 new mutations of the PK-LR gene

The PK-LR gene was studied in 23 patients with congenital haemolytic anaemia associated with erythrocyte pyruvate kinase (PK) deficiency. Twenty-seven different mutations were detected among the 42 mutated alleles identified: 19 missense mutations, four splice site mutations and one nonsense, one single base deletion and two large deletions. Seventeen of them (107G, 278T, 403T, 409A, 661A, 859C, 958A, 1094T, 1190T, 1209A, 1232C, 1369G, 507A, IVS9 -1c, IVS9 +43c [corrected] del C224, del 5006bp IVS3--> nt 1431) were new. Although all the exons, the flanking regions and the promoter were sequenced in all cases, we failed to detect the second expected mutation in four subjects. To correlate genotype to phenotype, the molecular results were related to the biochemical properties of the mutant enzymes by an analysis of the three-dimensional structure of erythrocyte PK. The new mutant 409A, found in association with the large deletion of 5006 bp in a newborn baby who died soon after birth, was functionally characterized by mutagenesis and in vitro expression of the protein to investigate its contribution in the severity of the clinical pattern. However, the biochemical data obtained for the mutant enzyme cannot explain the severe anaemia found in the PK-deficient patient hemizygous for this mutation.

Aspergillus surveillance project at a large tertiary-care hospital

A one-year surveillance project was conducted at a large tertiary hospital, which had extensive indoor renovation and extensive demolition/building at several nearby sites. This study collected viable fungi samples in the hospital every six days and analysed 74 duct dust samples for Aspergillus fumigatus mycelial asp f1 protein. Mean total fungi were 257.8 cfu/m3 outdoors, 53.2 cfu/m3 in all indoor samples and 83.5 cfu/m3 in the bone marrow transplant patient rooms. Mean total aspergillus was 6.8 cfu/m3 outdoors, 12.1 cfu/m3 in all indoor samples and 7.3 cfu/m3 in the bone marrow transplant patient rooms. The five most prevalent Aspergillus species collected inside the hospital (mean cfu/m3) were Aspergillus niger 7.57 cfu/m3, Aspergillus candidus 1.72 cfu/m3, Aspergillus flavus 0.97 cfu/m3, A. fumigatus 0.88 cfu/m3 and Aspergillus glaucus 0.45 cfu/m3. In rooms undergoing duct cleaning, mean A. fumigatus concentrations were 11.0 cfu/m3. Forty-eight of 74 (65%) duct dust samples had measurable levels of asp f1 protein, with a mean level of 0.41 ppm and maximum level of 1.94 ppm. Three major incidents involved increased hospital aspergillus concentrations. A. niger levels reached 680 cfu/m3 in an organ transplant room after a water leak from a ceiling pipe. Total aspergillus concentrations rose to 77 cfu/m3 in a bone marrow transplant patient room after improper sealing and water infiltration of the unit's dedicated high-efficiency particulate air filter system. Total aspergillus levels of 160 cfu/m3 were recorded in a renovation area during wood cutting. The higher concentrations of aspergillus seen inside the hospital compared with outdoors and the various moisture/HEPA filter/renovation incidents suggest that numerous small to moderate sources of aspergillus exist in the hospital.

Proximal versus distal hyperplastic polyps of the colorectum: different lesions or a biological spectrum?

BACKGROUND

Because of their suggested link with microsatellite instability high colorectal cancers, right sided hyperplastic polyps (HPs) may differ from their distally located counterparts. This is highlighted by the recognition of a variant HP, termed sessile serrated adenoma (SSA), which predominates in the proximal colon. HPs displaying the morphological features now associated with SSAs have been shown to have altered expression of "cancer associated" markers, but no studies have investigated whether this is dependent on anatomical location of the polyps.

AIMS

To evaluate morphological and functional features in right versus left sided HPs from patients without colorectal cancer with the aim of identifying distinguishing characteristics.

METHODS

HPs originating in the proximal and distal colorectum were histochemically and immunohistochemically stained to evaluate a panel of markers related to proliferation and differentiation. In addition, a series of morphological features was evaluated for each polyp.

RESULTS

Crypt serration, crypt dilatation, and horizontal crypt growth were more common among HPs from the right side, whereas histochemical factors including mucin changes, global methylation status, and expression of carcinoembryonic antigen were not significantly different. An age disparity was also seen between patients with right versus left sided lesions, with patients with right sided lesions being an average of more than 10 years younger than those with left sided lesions.

CONCLUSIONS

These findings suggest that right and left sided HPs differ mainly in terms of growth regulation rather than cellular differentiation, implying that these lesions belong to a continuous spectrum of serrated polyps that differ quantitatively rather than qualitatively.

A haplotype at the PARK3 locus influences onset age for Parkinson's disease: the GenePD study

OBJECTIVE

To identify a haplotype influencing onset age for Parkinson's disease (PD) in the PARK3 region on chromosome 2p13.

METHODS

Single nucleotide polymorphisms (SNP) spanning 2.2 Mb and located in or near potential candidate genes were used to fine map the PARK3 region in 527 patients with familial PD, from 264 families.

RESULTS

TT homozygotes for rs1876487 (G/T) had a 7.4-year younger mean age at onset (p = 0.005) compared to patients with GT and GG genotypes. Furthermore, SNP flanking the sepiapterin reductase (7,8-dihydrobiopterin: NADP+ oxidoreductase) (SPR) gene, rs1876487 (p = 0.02) and rs1150500 (p = 0.04), were associated with younger onset age among persons who did not carry the 174 allele of D2S1394. The SPR gene is implicated in dopamine synthesis. Haplotype analysis of three SNP-rs2421095, rs1876487, rs1561244-revealed an association with onset age (p = 0.023) and a haplotype of A-T-G alleles was associated with younger onset for PD (p = 0.005).

CONCLUSIONS

A haplotype at the PARK3 locus, harboring the SPR gene, is associated with onset age of PD. This may suggest a role for the SPR gene in modifying the age at onset of PD.

MR safety in patients with implanted deep brain stimulation systems (DBS)

INTRODUCTION

While it is desirable to perform MRI examinations in patients with deep brain stimulators (DBS), a major safety concern exists regarding the potential for excessive heating secondary to magnetically induced electrical currents. This study was designed to determine the safety of MRI and DBS.

METHODS

Standard configurations of DBS systems were tested. In vitro testing was performed using a 1.5-Tesla MR system, a gel-filled phantom, and the body and head RF coils with varying levels of RF energy (SAR). A fluoroptic thermometry system was used to record temperatures.

RESULTS

Using the 1.5-T MRI and body RF transmit coil, the temperature changes ranged from 2.5 to 25.3 degrees C. Using the 1.5-T MRI and head RF transmit coil, the temperature changes ranged from 2.3 to 7.1 degrees C.

CONCLUSIONS

Excessive heating does occur with certain MR imaging conditions. Under certain conditions determined in this study, patients with DBS may safely undergo anatomical MR imaging. In the future, standardized testing and more comprehensive studies will be needed to ensure the MR safety of neurostimulation systems.

Epstein-Barr virus (types 1 and 2) in the tear film in Sjogren's syndrome and HIV infection

Evidence of Epstein-Barr virus (EBV) shedding in the saliva and tear film has been sought to explain the pathogenesis of the oral and ocular features of Sjogren's syndrome. Patients with human immunodeficiency virus (HIV) infection are purported to have a higher incidence of keratoconjunctivitis sicca. Twenty patients with definite Sjogren's syndrome (primary and secondary), 19 with HIV infection, and 15 normal controls were recruited and studied. Human herpes viruses (EBV 1 and 2, CMV, HZV, and HSV-1) in tear film were detected by polymerase chain reaction of DNA extracted from Schirmer strips. HSV-1, VZV, and CMV were not detected in any tear samples. EBV-1 DNA was found in the tear film of 4 patients with Sjogren's syndrome, which was not significantly different from the control group (P = 0.18). Twelve patients with HIV infection had evidence of EBV-1 in their tears, which was significantly different from controls (P = 0.0002) and patients with Sjogren's syndrome (P = 0.014). EBV-2 was found in 3 patients with HIV and in 1 patient with secondary Sjogren's syndrome, and was always found as a co-infection with EBV-1 (P = 0.01). This represents the first report examining EBV types 1 and 2 in the tear film and also EBV in the tear film of patients with HIV. Shedding of EBV in the tear film was not related to the presence of keratoconjunctivitis sicca in Sjogren's syndrome. EBV-2 co-infection with EBV-1 has not been previously reported in the tear film. EBV infection is abnormally regulated in Sjogren's syndrome and HIV, and it is likely that the presence of EBV in the tear film is related to the patients' altered immune status.

A regulator gene for acetate utilisation from Neurospora crassa

The Neurospora crassa homologue of the Aspergillus nidulans regulatory gene facB has been cloned. The gene encodes a putative transcriptional activator of 865 amino acids that contains a DNA-binding domain with a Zn(II)(2)Cys(6) binuclear cluster, a linker region and a leucine zipper-like heptad repeat. Two internal amino acid sequences are identical to peptide sequences determined from proteolytic fragments of a DNA-binding protein complex specific for genes involved in acetate utilisation and expressed in acetate-induced mycelia of N. crassa. Recombinant expression of the predicted DNA-binding domain demonstrates that it is capable of independent recognition of a subset of the promoter sequences that bind the protein complex from N. crassa. A duplication-induced mutation in the corresponding gene results in an acetate non-utilising phenotype that is characterised by inefficient induction of the enzymes required for acetate utilisation. The new gene does not fall into any existing complementation group and has been designated acu-15.

Toxic equivalency factors for PAH and their applicability in shellfish pollution monitoring studies

Fish and shellfish are exposed to a wide range of polycyclic aromatic hydrocarbons (PAH) following oil spills at sea, and can become contaminated as a result. Finfish have a more effective mixed-function oxidase enzyme system than shellfish, and are therefore able to metabolise and excrete PAH more effectively than the invertebrates. Thus, contamination by high-molecular weight PAH, including those with carcinogenic potential and so of concern with regard to human consumers, is therefore usually observed in shellfish, and particularly in bivalve molluscs. Oil spills are not the sole source of PAH, however, as parent compounds are also generated by a wide range of combustion processes. In this paper, consideration is given to monitoring data gathered following recent oil spills (both of crude oil and diesel fuel), alongside data from other studies. These include studies conducted around a former gasworks site and downstream of an aluminium smelter in the UK, and from mussel monitoring studies undertaken in the UK and the USA (including the Exxon Valdez oil spill and the National Status and Trends programme), and in other countries in Europe. For comparative purposes the PAH concentrations are summed and also expressed as benzo[a]pyrene equivalents, their relative concentrations being weighted in relation to the carcinogenic potential of individual PAH compounds using toxic equivalency factors (TEF). Our aim was to assess the utility of this approach in fishery resource monitoring and control following oil spills. Certainly this approach seems useful from the data assessed in this study. and the relative ranking of the various studies seems to reflect the relative degree of concern for human consumers due to the differing contamination sources. As a simple tool for control purposes it is equally applicable to PAH derived from oil spills, and from industrial and combustion sources.

Epidemiologic study of 203 sibling pairs with Parkinson's disease: the GenePD study

OBJECTIVE

To examine patterns of familial aggregation and factors influencing onset age in a sample of siblings with PD.

METHODS

Sibling pairs (n = 203) with PD were collected as part of the GenePD study. Standardized family history, medical history, and risk factor data were collected and analyzed.

RESULTS

The mean age at onset was 61.4 years and did not differ according to sex, exposure to coffee, alcohol, or pesticides. Head trauma was associated with younger onset (p = 0.03) and multivitamin use with later onset (p = 0.007). Age at onset correlation between sibling pairs was significant (r = 0.56, p = 0.001) and was larger than the correlation in year of onset (r = 0.29). The mean difference in onset age between siblings was 8.7 years (range, 0 to 30 years). Female sex was associated with increased frequency of relatives with PD. The frequency of affected parents (7.0%) and siblings (5.1%) was increased when compared with frequency in spouses (2.0%).

CONCLUSIONS

The greater similarity for age at onset than for year of onset in sibling pairs with PD, together with increased risk for biological relatives over spouses of cases, supports a genetic component for PD. Risk to siblings in this series is increased over that seen in random series of PD cases; however, patients in this sample have similar ages at onset and sex distribution as seen for PD generally. These analyses suggest that factors influencing penetrance are critical to the understanding of this disease.

Expression of serotonin 5-HT(2A) receptors in the human cerebellum and alterations in schizophrenia

The occurrence of human cerebellar serotonin 5-HT(2A) receptors (5-HT(2A)R) is equivocal and their status in schizophrenia unknown. Using a range of techniques, we investigated cerebellar 5-HT(2A)R expression in 16 healthy subjects and 16 subjects with schizophrenia. Immunocytochemistry with a monoclonal antibody showed labelling of Purkinje cell bodies and dendrites, as well as putative astrocytes. Western blots showed a major band at approximately 45 kDa. Receptor autoradiography and homogenate binding with [(3)H]ketanserin revealed cerebellar 5-HT(2A)R binding sites present at levels approximately a third of that in prefrontal cortex. 5-HT(2A)R mRNA was detected by reverse transcriptase-polymerase chain reaction, with higher relative levels in men than women. Several aspects of 5-HT(2A)R expression were altered in schizophrenia. 5-HT(2A)R immunoreactivity in Purkinje cells was partially redistributed from soma to dendrites and was increased in white matter. 5-HT(2A)R mRNA was decreased in the male patients. 5-HT(2A)R measured by dot blots and [(3)H]ketanserin binding (B(max) and K(d)) were not significantly altered in schizophrenia. These data show that 5-HT(2A)R gene products (mRNA, protein, binding sites) are expressed in the human cerebellum at nonnegligible levels; this bears upon 5-HT(2A)R imaging studies which use the cerebellum as a reference region. 5-HT(2A)R expression is altered in schizophrenia; the shift of 5-HT(2A)R from soma to dendrites is noteworthy since atypical antipsychotics have the opposite effect. Finally, the results emphasise that expression of a receptor gene is a mutifaceted process. Measurement of multiple parameters is necessary to give a clear picture of the normal situation and to show the profile of alterations in a disease.

The slow mo mutation reduces pacemaker current and heart rate in adult zebrafish

Genetic studies in zebrafish have focused on embryonic mutations, but many physiological mechanisms continue to mature after embryogenesis. We report here that zebrafish homozygous for the mutation slow mo can be raised to adulthood. In the embryo, the slow mo gene is needed to regulate heart rate, and its mutation causes a reduction in pacemaker current (I(h)) and slowing of heart rate (bradycardia). The homozygous adult slow mo fish continues to manifest bradycardia, without other evident ill effects. Patch-clamp analysis of isolated adult cardiomyocytes reveals that I(h) has chamber-specific properties such that the atrial current density of I(h) is far greater than the ventricular current density of I(h). I(h) is markedly diminished in cardiomyocytes from both chambers of slow mo mutant fish. Thus I(h) continues to be a critical determinant of pacemaker rate even after adult neural and humoral influences have developed. It is clear that zebrafish may be used for genetic dissection of selected physiological mechanisms in the adult.

The aging voice: a review, treatment data and familial and genetic perspectives

This paper will provide a review of aspects of vocal aging within the context of general body aging and describe two data sets related to the aging voice. Data will be presented which document pre- to posttreatment improvement in select voice characteristics (sound pressure level, subglottal air pressure, thyroarytenoid laryngeal muscle activity and voice quality) following application of an intensive voice treatment program (the LSVT) to 3 individuals with aged voice. Additionally, physiological data (forced expiratory volume, visual accommodation, bone density, taste discrimination, white blood count and resting heart rate) and select perceptual (perceived age) and acoustic measures (reflecting both cycle-to-cycle and longer-term intensity and frequency stability) from 67 subjects will be reviewed from the work of Gray and colleagues to document the differential impact of the global aging process across organ systems including the aging voice.

Growth and function of the embryonic heart depend upon the cardiac-specific L-type calcium channel alpha1 subunit

The heart must function from the moment of its embryonic assembly, but the molecular underpinnings of the first heart beat are not known, nor whether function determines form at this early stage. Here, we find by positional cloning that the embryonic lethal island beat (isl) mutation in zebrafish disrupts the alpha1 C L-type calcium channel subunit (C-LTCC). The isl atrium is relatively normal in size, and individual cells contract chaotically, in a pattern resembling atrial fibrillation. The ventricle is completely silent. Unlike another mutation with a silent ventricle, isl fails to acquire the normal number of myocytes. Thus, calcium signaling via C-LTCC can regulate heart growth independently of contraction, and plays distinctive roles in fashioning both form and function of the two developing chambers.

The effect of differing scoring methods for the Tower of London task on developmental patterns of performance

The Tower of London (TOL) task is frequently used to assess executive functioning in both adults and children, although there remains considerable controversy over what it measures and how to score it. In this study we compare two scoring methods and find that correlations between them were high for 7-year-olds (.86), and dropped to a low of .47 for adults. These results demonstrate that the TOL necessarily has different construct validity in adults and children. Second, results of one method (based on errors only) show a developmental trend in performance from middle childhood to adulthood, while the other (based on errors and time) shows a developmental progression from ages 7 to 13, but not between 13-year-olds and young adults. Thus, scoring method influences the resulting developmental model.