Advanced glycation end-products: a review

Advanced glycation end-products are a complex and heterogeneous group of compounds that have been implicated in diabetes related complications. At present it is not known if they are the cause or the consequence of the complications observed. We discuss the chemistry of advanced glycated end-product formation and their patho-biochemistry particularly in relation to the diabetic microvascular complications of retinopathy, neuropathy and nephropathy as well as their role in the accelerated vasculopathy observed in diabetes. The concept of carbonyl stress as a cause for advanced glycated end-product toxicity is mentioned. We discuss alterations in the concentrations of advanced glycated end-products in the body, particularly in relation to changes occurring with age, diabetes and its complications such as nephropathy. Problems relating to current methods of advanced glycated end-product detection and measurement are highlighted including the lack of a universally established method of detection or unit of measurement. Agents used for the treatment of advanced glycated end-product accumulation are reviewed, with an emphasis on the results of the recent phase III trials using aminoguanidine and diabetes related complications.

Observation of Gravitational Waves from a Binary Black Hole Merger

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

Febrile seizures and generalized epilepsy associated with a mutation in the Na+-channel beta1 subunit gene SCN1B

Febrile seizures affect approximately 3% of all children under six years of age and are by far the most common seizure disorder. A small proportion of children with febrile seizures later develop ongoing epilepsy with afebrile seizures. Segregation analysis suggests the majority of cases have complex inheritance but rare families show apparent autosomal dominant inheritance. Two putative loci have been mapped (FEB1 and FEB2), but specific genes have not yet been identified. We recently described a clinical subset, termed generalized epilepsy with febrile seizures plus (GEFS+), in which many family members have seizures with fever that may persist beyond six years of age or be associated with afebrile generalized seizures. We now report linkage, in another large GEFS+ family, to chromosome region 19q13.1 and identification of a mutation in the voltage-gated sodium (Na+)-channel beta1 subunit gene (SCN1B). The mutation changes a conserved cysteine residue disrupting a putative disulfide bridge which normally maintains an extracellular immunoglobulin-like fold. Co-expression of the mutant beta1 subunit with a brain Na+-channel alpha subunit in Xenopus laevis oocytes demonstrates that the mutation interferes with the ability of the subunit to modulate channel-gating kinetics consistent with a loss-of-function allele. This observation develops the theme that idiopathic epilepsies are a family of channelopathies and raises the possibility of involvement of other Na+-channel subunit genes in febrile seizures and generalized epilepsies with complex inheritance patterns.

Distinct binding specificities and functions of higher eukaryotic polypyrimidine tract-binding proteins

In higher eukaryotes, the polypyrimidine-tract (Py-tract) adjacent to the 3' splice site is recognized by several proteins, including the essential splicing factor U2AF65, the splicing regulator Sex-lethal (Sxl), and polypyrimidine tract-binding protein (PTB), whose function is unknown. Iterative in vitro genetic selection was used to show that these proteins have distinct sequence preferences. The uridine-rich degenerate sequences selected by U2AF65 are similar to those present in the diverse array of natural metazoan Py-tracts. In contrast, the Sxl-consensus is a highly specific sequence, which can help explain the ability of Sxl to regulate splicing of transformer pre-mRNA and autoregulate splicing of its own pre-mRNA. The PTB-consensus is not a typical Py-tract; it can be found in certain alternatively spliced pre-mRNAs that undergo negative regulation. Here it is shown that PTB can regulate alternative splicing by selectively repressing 3' splice sites that contain a PTB-binding site.

Sequence-specific binding of transfer RNA by glyceraldehyde-3-phosphate dehydrogenase

A transfer RNA (tRNA) binding protein present in HeLa cell nuclear extracts was purified and identified as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Studies with mutant tRNAs indicated that GAPDH recognizes both sequence and structural features in the RNA. GAPDH discriminated between wild-type tRNA and two tRNA mutants that are defective in nuclear export, which suggests that the protein may participate in RNA export. The cofactor nicotinamide adenine dinucleotide disrupted complex formation between tRNA and GAPDH and thus may share a common binding site with the RNA. Indirect immunofluorescence experiments showed that GAPDH is present in the nucleus as well as in the cytoplasm.

Detection of curcumin and its metabolites in hepatic tissue and portal blood of patients following oral administration

Studies in vitro and in animal models of colorectal and hepatocellular cancers suggest that curcumin is an effective chemopreventive agent. In this pilot trial, we investigated whether oral administration of curcumin results in concentrations of the agent in normal and malignant human liver tissue, which are sufficient to elicit pharmacological activity. In total, 12 patients with hepatic metastases from colorectal cancer received 450–3600 mg of curcumin daily, for 1 week prior to surgery. Levels of curcumin and its metabolites were measured by HPLC in portal and peripheral blood, bile and liver tissue. Curcumin was poorly available, following oral administration, with low nanomolar levels of the parent compound and its glucuronide and sulphate conjugates found in the peripheral or portal circulation. While curcumin was not found in liver tissue, trace levels of products of its metabolic reduction were detected. In patients who had received curcumin, levels of malondialdehyde-DNA (M₁G) adduct, which reflect oxidative DNA changes, were not decreased in post-treatment normal and malignant liver tissue when compared to pretreatment samples. The results suggest that doses of curcumin required to furnish hepatic levels sufficient to exert pharmacological activity are probably not feasible in humans.

Randomised controlled trial of cardioprotective diet in patients with recent acute myocardial infarction: results of one year follow up

OBJECTIVE

To test whether a fat reduced diet rich in soluble dietary fibre, antioxidant vitamins, and minerals reduces complications and mortality after acute myocardial infarction.

DESIGN

Randomised, single blind, controlled trial.

SETTING

Primary and secondary care research centre for patients with myocardial infarction.

SUBJECTS

505 patients with suspected acute myocardial infarction. Those with definite or possible acute myocardial infarction and unstable angina based on World Health Organisation criteria were assigned to diet A (n = 204) or diet B (n = 202) within 24-48 hours of infarction.

INTERVENTIONS

Both groups were advised to follow a fat reduced diet. Group A was also advised to eat more fruit, vegetables, nuts, and grain products.

MAIN OUTCOME MEASURES

Mortality from cardiac disease and other causes. Serum lipid concentrations and compliance with diet.

RESULTS

Blood lipoprotein concentrations and body weight fell significantly in patients in group A compared with those in group B (cholesterol fell by 0.74 mmol/l in group A v 0.32 mmol/l in group B, 95% confidence interval of difference 0.14 to 0.70, and weight by 7.1 v 3.0 kg, 0.52 to 7.68). The incidence of cardiac events was significantly lower in group A than group B (50 v 82 patients, p less than 0.001). Group A also had lower total mortality (21 v 38 died, p less than 0.01) than group B.

CONCLUSIONS

Comprehensive dietary changes in conjunction with weight loss immediately after acute myocardial infarction may modulate blood lipoproteins and significantly reduce complications and mortality after one year.

GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence

We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5σ. The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak gravitational strain of 3.4_{-0.9}^{+0.7}×10^{-22}. The inferred source-frame initial black hole masses are 14.2_{-3.7}^{+8.3}M_{⊙} and 7.5_{-2.3}^{+2.3}M_{⊙}, and the final black hole mass is 20.8_{-1.7}^{+6.1}M_{⊙}. We find that at least one of the component black holes has spin greater than 0.2. This source is located at a luminosity distance of 440_{-190}^{+180}  Mpc corresponding to a redshift of 0.09_{-0.04}^{+0.03}. All uncertainties define a 90% credible interval. This second gravitational-wave observation provides improved constraints on stellar populations and on deviations from general relativity.

Cyclooxygenase-2, malondialdehyde and pyrimidopurinone adducts of deoxyguanosine in human colon cells

Cyclooxygenases (COX) catalyse the oxygenation of arachidonic acid to prostaglandin (PG) endoperoxides. Activity of one of the COX isoforms, COX-2, results in production of prostaglandin E(2) (PGE(2)) via the endoperoxide PGH(2). COX-2 has been implicated in the pathogenesis of colorectal cancer. Malondialdehyde (MDA) is a mutagen produced by spontaneous and enzymatic breakdown of PGH(2). MDA reacts with DNA to form adducts, predominantly the pyrimidopurinone adduct of deoxyguanosine (M(1)G). Here the hypothesis was tested that COX-2 activity in human colon cells results in formation of MDA and generation of M(1)G adducts. M(1)G was detected in basal cultures of human non-malignant colon epithelial (HCEC) and malignant SW48, SW480, HT29 and HCA-7 colon cells, at levels from 77 to 148 adducts/10(8) nucleotides. Only HCA-7 and HT29 cells expressed COX-2 protein. Levels of M(1)G correlated significantly (r = 0.98, P < 0.001) with those of intracellular MDA determined colorimetrically in the four malignant cell types, but neither parameter correlated with expression of COX-2 or PG biosynthesis. Induction of COX-2 expression by phorbol 12-myristate 13-acetate in HCEC cells increased PGE(2) production 20-fold and MDA concentration 3-fold. Selective inhibition of COX-2 activity in HCA-7 cells by NS-398 significantly inhibited PGE(2) production, but altered neither MDA nor M(1)G levels. Malondialdehyde treatment of HCEC cells resulted in a doubling of M(1)G levels. These results show for the first time in human colon cells that COX-2 activity is associated with formation of the endogenous mutagen, MDA. Moreover, they demonstrate the correlation between MDA concentration and M(1)G adduct levels in malignant cells.

Neuronal sodium-channel alpha1-subunit mutations in generalized epilepsy with febrile seizures plus

Generalized epilepsy with febrile seizures plus (GEFS+) is a familial epilepsy syndrome characterized by the presence of febrile and afebrile seizures. The first gene, GEFS1, was mapped to chromosome 19q and was identified as the sodium-channel beta1-subunit, SCN1B. A second locus on chromosome 2q, GEFS2, was recently identified as the sodium-channel alpha1-subunit, SCN1A. Single-stranded conformation analysis (SSCA) of SCN1A was performed in 53 unrelated index cases to estimate the frequency of mutations in patients with GEFS+. No mutations were found in 17 isolated cases of GEFS+. Three novel SCN1A mutations-D188V, V1353L, and I1656M-were found in 36 familial cases; of the remaining 33 families, 3 had mutations in SCN1B. On the basis of SSCA, the combined frequency of SCN1A and SCN1B mutations in familial cases of GEFS+ was found to be 17%.

The protein Sex-lethal antagonizes the splicing factor U2AF to regulate alternative splicing of transformer pre-mRNA

Somatic sexual differentiation in Drosophila melanogaster involves a cascade of regulated splicing events and provides an attractive model system for the analysis of alternative splicing mechanisms. The protein Sex-lethal (Sxl) activates a female-specific 3' splice site in the first intron of transformer (tra) pre-mRNA while repressing an alternative non-sex-specific site. We have developed an in vitro system that recapitulates this regulation in a manner consistent with genetic, transfection and fly transformation studies. Using this system, we have determined the molecular basis of the splice site switch. Here we show that Sxl inhibits splicing to the non-sex-specific (default) site by specifically binding to its polypyrimidine tract, blocking the binding of the essential splicing factor U2AF. This enables U2AF to activate the lower-affinity female-specific site. A splicing 'effector' domain present in U2AF but absent from Sxl accounts for the different activities of these two polypyrimidine-tract-binding proteins: addition of the U2AF effector domain to Sxl converts it from a splicing repressor to an activator and renders it unable to mediate splice-site switching.

Interaction of U2AF65 RS region with pre-mRNA branch point and promotion of base pairing with U2 snRNA [corrected]

The mammalian splicing factor U2AF65 binds to the polypyrimidine tract adjacent to the 3' splice site and promotes assembly of U2 small nuclear ribonucleoprotein on the upstream branch point, an interaction that involves base pairing with U2 small nuclear RNA (snRNA). U2AF65 contains an RNA binding domain, required for interaction with the polypyrimidine tract, and an arginine-serine-rich (RS) region, required for U2 snRNP recruitment and splicing. Here it is reported that binding of U2AF65 to the polypyrimidine tract directed the RS domain to contact the branch point and promoted U2 snRNA-branch point base pairing even in the absence of other splicing factors. Analysis of RS domain mutants indicated that the ability of U2AF65 to contact the branch point, to promote the U2 snRNA-branch point interaction, and to support splicing are related activities, requiring only a few basic amino acids. Thus, the U2AF65 RS domain plays a direct role in modulating spliceosomal RNA-RNA interactions.

GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2

We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31.2_{-6.0}^{+8.4}M_{⊙} and 19.4_{-5.9}^{+5.3}M_{⊙} (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination of the spin components perpendicular to the orbital plane, χ_{eff}=-0.12_{-0.30}^{+0.21}. This result implies that spin configurations with both component spins positively aligned with the orbital angular momentum are disfavored. The source luminosity distance is 880_{-390}^{+450}  Mpc corresponding to a redshift of z=0.18_{-0.07}^{+0.08}. We constrain the magnitude of modifications to the gravitational-wave dispersion relation and perform null tests of general relativity. Assuming that gravitons are dispersed in vacuum like massive particles, we bound the graviton mass to m_{g}≤7.7×10^{-23}  eV/c^{2}. In all cases, we find that GW170104 is consistent with general relativity.

Lung overexpression of the vascular endothelial growth factor gene induces pulmonary edema

We hypothesized that the angiogenic mediator, vascular endothelial growth factor (VEGF), known to be expressed in the lung and to be capable of inducing local edema in skin, might evoke the development of lung edema if expressed in excess amounts. To test this hypothesis, we developed an in vivo model of VEGF overexpression in the lung on the basis of delivery to the respiratory epithelium of the VEGF165 complementary DNA by an E1(-) adenovirus vector (AdVEGF165). Administration of AdVEGF165 by the intratracheal route (10(9) plaque-forming units [pfu]) to C57Bl/6 mice showed increased expression of VEGF messenger RNA in lung tissue by Northern analysis. Overexpression of VEGF protein in the lung at Days 1 to 10 was confirmed by enzyme-linked immunosorbent assay. Intratracheal administration of AdVEGF165 resulted in a dose-dependent increase in lung wet/dry weight ratios over time, lung histology showed widespread intra- alveolar edema, and pulmonary capillary permeability was significantly increased as quantified by the Evans blue dye assay and [(131)I]albumin permeability. To confirm the specificity of these observations, mice were pretreated with intranasal administration of an adenovirus vector expressing a truncated soluble form of the VEGF receptor flt-1 (Adsflt). Adsflt (10(9) pfu) pretreatment completely abrogated the increased lung wet/dry weight ratio caused by AdVEGF165 administration, whereas an identical adenovirus vector with an irrelevant transgene had no effect upon subsequent AdVEGF165-induced pulmonary edema. Together, these data suggest that overexpression of VEGF in the lung may be one mechanism of increased pulmonary vascular permeability in the early stages of acute lung injury.

Laparoscopic versus open inguinal hernia repair: randomised prospective trial

Laparoscopic surgery benefits patients because it reduces pain and enables earlier mobilisation. There is concern that laparoscopic hernia repair may enter surgical practice without proper evaluation. We have done a randomised, prospective study comparing laparoscopic and open inguinal hernia repair performed under day-case general anaesthesia. 150 patients were randomised to have laparoscopic (group L) or open (group O) herniorrhaphy. Group L underwent transabdominal stapling of preperitoneal Prolene mesh. Group O underwent open repair, with a tension-free nylon darn. Postoperatively patients completed pain analogue scales eight times over 7 days, and use of analgesia was recorded. Time of return to normal domestic activity and to work was assessed. The groups were similar in age, sex, and body surface area. Self-administered co-proxamol was a median of 18 tablets (1 tablet = 325 mg) in group O (n = 75) and 6 in group L (n = 75, p < 0.001). Overall mean pain analogue score was 3.1 (SD 1.8, n = 70) in group O and 1.8 (SD 1.1, n = 71) in group L (p < 0.0001). Return to normal domestic activity was a median of 7 days in group O (n = 72) and 3 days in group L (n = 73) (p < 0.001). Return to work was a median of 28 days in group O (n = 39) and 14 days in group L (n = 40) (p < 0.002). These data suggest that laparoscopic hernia repair induces less pain than open hernia repair, and enables patients to return to normal activity and work more quickly.

Randomised controlled trial of laparoscopic versus open mesh repair for inguinal hernia: outcome and cost

OBJECTIVE

To compare tension-free open mesh hernioplasty under local anaesthetic with transabdominal preperitoneal laparoscopic hernia repair under general anaesthetic.

DESIGN

A randomised controlled trial of 403 patients with inguinal hernias.

SETTING

Two acute general hospitals in London between May 1995 and December 1996.

SUBJECTS

400 patients with a diagnosis of groin hernia, 200 in each group.

MAIN OUTCOME MEASURES

Time until discharge, postoperative pain, and complications; patients' perceived health (SF-36), duration of convalescence, and patients' satisfaction with surgery; and health service costs.

RESULTS

More patients in the open group (96%) than in the laparoscopic group (89%) were discharged on the same day as the operation (chi2 = 6.7; 1 df; P=0.01). Although pain scores were lower in the open group while the effect of the local anaesthetic persisted (proportional odds ratio at 2 hours 3.5 (2.3 to 5.1)), scores after open repair were significantly higher for each day of the first week (0.5 (0.3 to 0.7) on day 7) and during the second week (0.7 (0.5 to 0.9)). At 1 month there was a greater improvement (or less deterioration) in mean SF-36 scores over baseline in the laparoscopic group compared with the open group on seven of eight dimensions, reaching significance on five. For every activity considered the median time until return to normal was significantly shorter for the laparoscopic group. Patients randomised to laparoscopic repair were more satisfied with surgery at 1 month and 3 months after surgery. The mean cost per patient of laparoscopic repair was 335 pounds (95% confidence interval 228 pounds to 441 pounds) more than the cost of open repair.

CONCLUSION

This study confirms that laparoscopic hernia repair has considerable short term clinical advantages after discharge compared with open mesh hernioplasty, although it was more expensive.

A multicentre observational study on the epidemiology, risk factors, management and outcomes of mucormycosis in India

OBJECTIVES

To describe the epidemiology, management and outcome of individuals with mucormycosis; and to evaluate the risk factors associated with mortality.

METHODS

We conducted a prospective observational study involving consecutive individuals with proven mucormycosis across 12 centres from India. The demographic profile, microbiology, predisposing factors, management and 90-day mortality were recorded; risk factors for mortality were analysed.

RESULTS

We included 465 patients. Rhino-orbital mucormycosis was the most common (315/465, 67.7%) presentation followed by pulmonary (62/465, 13.3%), cutaneous (49/465, 10.5%), and others. The predisposing factors included diabetes mellitus (342/465, 73.5%), malignancy (42/465, 9.0%), transplant (36/465, 7.7%), and others. Rhizopus species (231/290, 79.7%) were the most common followed by Apophysomyces variabilis (23/290, 7.9%), and several rare Mucorales. Surgical treatment was performed in 62.2% (289/465) of the participants. Amphotericin B was the primary therapy in 81.9% (381/465), and posaconazole was used as combination therapy in 53 (11.4%) individuals. Antifungal therapy was inappropriate in 7.6% (30/394) of the individuals. The 90-day mortality rate was 52% (242/465). On multivariate analysis, disseminated and rhino-orbital (with cerebral extension) mucormycosis, shorter duration of symptoms, shorter duration of antifungal therapy, and treatment with amphotericin B deoxycholate (versus liposomal) were independent risk factors of mortality. A combined medical and surgical management was associated with a better survival.

CONCLUSIONS

Diabetes mellitus was the dominant predisposing factor in all forms of mucormycosis. Combined surgical and medical management was associated with better outcomes. Several gaps surfaced in the management of mucormycosis. The rarer Mucorales identified in the study warrant further evaluation.

Effect of vitamin levels on biomarkers of exposure and oxidative damage-the EXPAH study

DNA adducts are markers of carcinogen exposure and of their biological effect; they have been shown to be related to mutagenesis, and therefore they could be a predictive biomarker of human cancer. The objective of this study was to assess if there is a relationship between vitamins A, C, and E, which are known to play a significant role as free radical scavengers and antioxidant agents, and biomarkers of genotoxicity and oxidative stress. Three hundred and fifty-six subjects from Czech Republic, Slovak Republic and Bulgaria, who completed a questionnaire on dietary information and had a measurement of plasma A, C, E vitamins, DNA adduct levels (benzo[a]pyrene (B[a]P) and bulky (DNA-Tot) DNA adducts) and oxidative damage (cyclic pyrimidopurinone N-1,N2 malondialdehyde-2 deoxyguanosine (M1dG) and 8-oxo-7,8-dihydro-2_deoxyguanosine (8-oxodG)) were analyzed. A significant inverse correlation was observed between plasma vitamin levels and both benzo[a]pyrene (B[a]P) and bulky DNA adducts. Vitamin A was also significantly inversely correlated with M1dG, a marker of oxidative damage. The associations were stronger in non-smokers than in smokers. Dietary intake of certain antioxidants such as vitamins is associated with reduced levels of markers of DNA damage (B[a]P and DNA-Tot) and oxidation (M1dG and 8-oxodG) measured in peripheral white blood cells. This could contribute to the protective role of such a dietary pattern on cancer risk. The protective effect of dietary vitamins is less evident in smokers.

Evidence for linkage of a candidate chromosome 1 region to human systemic lupus erythematosus

Genetic susceptibility confers significant risk for systemic lupus erythematosus (SLE). The MHC region and other polymorphic loci have been associated with SLE. Because more compelling evidence for an involvement of a genetic locus includes linkage, we tested a candidate region homologous to a murine SLE susceptibility region in 52 SLE-affected sibpairs from three ethnic groups. We analyzed seven microsatellite markers from the human chromosome 1q31-q42 region corresponding to the telomeric end of mouse chromosome 1, the region where specific manifestations of murine lupus, including glomerulonephritis and IgG antichromatin, have been mapped. Comparing the mean allele sharing in affected sibpairs of each of these seven markers to their expected values of 0.50, only the five markers located at 1q41-q42 showed evidence for linkage (P = 0.0005-0.08). Serum levels of IgG antichromatin also showed evidence for linkage to two of these five markers (P = 0.04), suggesting that this phenotype is conserved between mice and humans. Compared to the expected random distribution, the trend of increased sharing of haplotypes was observed in affected sibpairs from three ethnic groups (P < 0.01). We concluded that this candidate 1q41-q42 region probably contains a susceptibility gene(s) that confers risk for SLE in multiple ethnic groups.

Identification of a human neuroectodermal tumor antigen (OFA-I-2) as ganglioside GD2

Two monospecific human antibodies (anti-OFA-I-1 and anti-OFA-I-2) produced in vitro by lymphoblast cell lines originating from melanoma patients have been shown previously to recognize cell surface antigens (OFA-I-1 and OFA-I-2) on human tumors and fetal brain: OFA-I-1 is expressed on a variety of human tumors, while OFA-I-2 has been detected only on tumors of neuroectodermal origin. Evidence presented in this report suggests that the two antigens expressed by a cultured human melanoma cell line (M14) are chemically distinct and that OFA-I-2 is a cell surface glycolipid, ganglioside GD2: GalNAc beta 1 leads to 4 NeuAc alpha 2 leads to 8NeuAc alpha 2 leads to 3 Gal beta 1 leads to 4Glc-ceramide.

Transferable EST-SSR markers for the study of polymorphism and genetic diversity in bread wheat

Nearly 900 SSRs (simple sequence repeats) were identified among 15,000 ESTs (expressed sequence tags) belonging to bread wheat ( Triticum aestivumL.). The SSRs were defined by their minimum length, which ranged from 14 to 21 bp. The maximum length ranged from 24 to 87 bp depending upon the length of the repeat unit itself (1-7 bp). The average density of SSRs was one SSR per 9.2 kb of EST sequence screened. The trinucleotide repeats were the most abundant SSRs detected. As a representative sample, 78 primer pairs were designed, which were also used to screen the dbEST entries for Hordeum vulgare and Triticum tauschii (donor of the D-genome of cultivated wheat) using a cut-off E (expectation) value of 0.01. On the basis of in silico analysis, up to 55.12% of the primer pairs exhibited transferability from Triticum to Hordeum, indicating that the sequences flanking the SSRs are not only conserved within a single genus but also between related genera in Poaceae. Primer pairs for the 78 SSRs were synthesized and used successfully for the study of (1) their transferability to 18 related wild species and five cereal species (barley, oat, rye, rice and maize); and (2) polymorphism between the parents of four mapping populations available with us. A subset of 20 EST-SSR primers was also used to assess genetic diversity in a collection of 52 elite exotic wheat genotypes. This was done with a view to compare their utility relative to other molecular markers (gSSRs, AFLPs, and SAMPL) previously used by us for the same purpose with the same set of 52 bread wheat genotypes. Although only a low level of polymorphism was detected, relative to that observed with genomic SSRs, the study suggested that EST-SSRs can be successfully used for a variety of purposes, and may actually prove superior to SSR markers extracted from genomic libraries for diversity estimation and transferability.

Endoscopic tri-modal imaging for detection of early neoplasia in Barrett's oesophagus: a multi-centre feasibility study using high-resolution endoscopy, autofluorescence imaging and narrow band imaging incorporated in one endoscopy system

OBJECTIVE

To investigate the diagnostic potential of endoscopic tri-modal imaging and the relative contribution of each imaging modality (i.e. high-resolution endoscopy (HRE), autofluorescence imaging (AFI) and narrow-band imaging (NBI)) for the detection of early neoplasia in Barrett's oesophagus.

DESIGN

Prospective multi-centre study.

SETTING

Tertiary referral centres.

PATIENTS

84 Patients with Barrett's oesophagus.

INTERVENTIONS

The Barrett's oesophagus was inspected with HRE followed by AFI. All lesions detected with HRE and/or AFI were subsequently inspected in detail by NBI for the presence of abnormal mucosal and/or microvascular patterns. Biopsies were obtained from all suspicious lesions for blinded histopathological assessment followed by random biopsies.

MAIN OUTCOME MEASURES

(1) Number of patients with early neoplasia diagnosed by HRE and AFI; (2) number of lesions with early neoplasia detected with HRE and AFI; and (3) reduction of false positive AFI findings after NBI.

RESULTS

Per patient analysis: AFI identified all 16 patients with early neoplasia identified with HRE and detected an additional 11 patients with early neoplasia that were not identified with HRE. In three patients no abnormalities were seen but random biopsies revealed HGIN. After HRE inspection, AFI detected an additional 102 lesions; 19 contained HGIN/EC (false positive rate of AFI after HRE: 81%). Detailed inspection with NBI reduced this false positive rate to 26%.

CONCLUSIONS

In this international multi-centre study, the addition of AFI to HRE increased the detection of both the number of patients and the number of lesions with early neoplasia in patients with Barrett's oesophagus. The false positive rate of AFI was reduced after detailed inspection with NBI.

Tests of General Relativity with GW150914

The LIGO detection of GW150914 provides an unprecedented opportunity to study the two-body motion of a compact-object binary in the large-velocity, highly nonlinear regime, and to witness the final merger of the binary and the excitation of uniquely relativistic modes of the gravitational field. We carry out several investigations to determine whether GW150914 is consistent with a binary black-hole merger in general relativity. We find that the final remnant's mass and spin, as determined from the low-frequency (inspiral) and high-frequency (postinspiral) phases of the signal, are mutually consistent with the binary black-hole solution in general relativity. Furthermore, the data following the peak of GW150914 are consistent with the least-damped quasinormal mode inferred from the mass and spin of the remnant black hole. By using waveform models that allow for parametrized general-relativity violations during the inspiral and merger phases, we perform quantitative tests on the gravitational-wave phase in the dynamical regime and we determine the first empirical bounds on several high-order post-Newtonian coefficients. We constrain the graviton Compton wavelength, assuming that gravitons are dispersed in vacuum in the same way as particles with mass, obtaining a 90%-confidence lower bound of 10^{13}  km. In conclusion, within our statistical uncertainties, we find no evidence for violations of general relativity in the genuinely strong-field regime of gravity.