Mendelian randomization analysis of 34,497 German Holstein cows to infer causal associations between milk production and health traits

BACKGROUND

Claw diseases and mastitis represent the most important health issues in dairy cattle with a frequently mentioned connection to milk production. Although many studies have aimed at investigating this connection in more detail by estimating genetic correlations, they do not provide information about causality. An alternative is to carry out Mendelian randomization (MR) studies using genetic variants to investigate the effect of an exposure on an outcome trait mediated by genetic variants. No study has yet investigated the causal association of milk yield (MY) with health traits in dairy cattle. Hence, we performed a MR analysis of MY and seven health traits using imputed whole-genome sequence data from 34,497 German Holstein cows. We applied a method that uses summary statistics and removes horizontal pleiotropic variants (having an effect on both traits), which improves the power and unbiasedness of MR studies. In addition, genetic correlations between MY and each health trait were estimated to compare them with the estimates of causal effects that we expected.

RESULTS

All genetic correlations between MY and each health trait were negative, ranging from - 0.303 (mastitis) to - 0.019 (digital dermatitis), which indicates a reduced health status as MY increases. The only non-significant correlation was between MY and digital dermatitis. In addition, each causal association was negative, ranging from - 0.131 (mastitis) to - 0.034 (laminitis), but the number of significant associations was reduced to five nominal and two experiment-wide significant results. The latter were between MY and mastitis and between MY and digital phlegmon. Horizontal pleiotropic variants were identified for mastitis, digital dermatitis and digital phlegmon. They were located within or nearby variants that were previously reported to have a horizontal pleiotropic effect, e.g., on milk production and somatic cell count.

CONCLUSIONS

Our results confirm the known negative genetic connection between health traits and MY in dairy cattle. In addition, they provide new information about causality, which for example points to the negative energy balance mediating the connection between these traits. This knowledge helps to better understand whether the negative genetic correlation is based on pleiotropy, linkage between causal variants for both trait complexes, or indeed on a causal association.

Genomic dissection of the correlation between milk yield and various health traits using functional and evolutionary information about imputed sequence variants of 34,497 German Holstein cows

BACKGROUND

Over the last decades, it was subject of many studies to investigate the genomic connection of milk production and health traits in dairy cattle. Thereby, incorporating functional information in genomic analyses has been shown to improve the understanding of biological and molecular mechanisms shaping complex traits and the accuracies of genomic prediction, especially in small populations and across-breed settings. Still, little is known about the contribution of different functional and evolutionary genome partitioning subsets to milk production and dairy health. Thus, we performed a uni- and a bivariate analysis of milk yield (MY) and eight health traits using a set of ~34,497 German Holstein cows with 50K chip genotypes and ~17 million imputed sequence variants divided into 27 subsets depending on their functional and evolutionary annotation. In the bivariate analysis, eight trait-combinations were observed that contrasted MY with each health trait. Two genomic relationship matrices (GRM) were included, one consisting of the 50K chip variants and one consisting of each set of subset variants, to obtain subset heritabilities and genetic correlations. In addition, 50K chip heritabilities and genetic correlations were estimated applying merely the 50K GRM.

RESULTS

In general, 50K chip heritabilities were larger than the subset heritabilities. The largest heritabilities were found for MY, which was 0.4358 for the 50K and 0.2757 for the subset heritabilities. Whereas all 50K genetic correlations were negative, subset genetic correlations were both, positive and negative (ranging from -0.9324 between MY and mastitis to 0.6662 between MY and digital dermatitis). The subsets containing variants which were annotated as noncoding related, splice sites, untranslated regions, metabolic quantitative trait loci, and young variants ranked highest in terms of their contribution to the traits` genetic variance. We were able to show that linkage disequilibrium between subset variants and adjacent variants did not cause these subsets` high effect.

CONCLUSION

Our results confirm the connection of milk production and health traits in dairy cattle via the animals` metabolic state. In addition, they highlight the potential of including functional information in genomic analyses, which helps to dissect the extent and direction of the observed traits` connection in more detail.

How economic weights translate into genetic and phenotypic progress, and vice versa

BACKGROUND

This paper highlights the relationships between economic weights, genetic progress, and phenotypic progress in genomic breeding programs that aim at generating genetic progress in complex, i.e., multi-trait, breeding objectives via a combination of estimated breeding values for different trait complexes.

RESULTS

Based on classical selection index theory in combination with quantitative genetic models, we provide a methodological framework for calculating expected genetic and phenotypic progress for all components of a complex breeding objective. We further provide an approach to study the sensitivity of the system to modifications, e.g. to changes in the economic weights. We propose a novel approach to derive the covariance structure of the stochastic errors of estimated breeding values from the observed correlations of estimated breeding values. We define 'realized economic weights' as those weights that would coincide with the observed composition of the genetic trend and show, how they can be calculated. The suggested methodology is illustrated with an index that aims at achieving a breeding goal composed of six trait complexes, that was applied in German Holstein cattle breeding until 2021.

CONCLUSIONS

Based on the presented results, the main conclusions are (i) the composition of the observed genetic progress matches the expectations well, with predictions being slightly better when the covariance of estimation errors is taken into account; (ii) the composition of the expected phenotypic trend deviates significantly from the expected genetic trend due to the differences in trait heritabilities; and (iii) the realized economic weights derived from the observed genetic trend deviate substantially from the predefined ones, in one case even with a reversed sign. Further results highlight the implications of the change to a modified breeding goal based on the example of a new index comprising eight, partly new, trait complexes, which is used since 2021 in the German Holstein breeding program. The proposed framework and the analytical tools and software provided will be useful to define more rational and generally accepted breeding objectives in the future.

Genomic dominance variance analysis of health and milk production traits in German Holstein cattle

Genomic analyses commonly explore the additive genetic variance of traits. The non-additive variance, however, is usually small but often significant in dairy cattle. This study aimed at dissecting the genetic variance of eight health traits that recently entered the total merit index in Germany and the somatic cell score (SCS), as well as four milk production traits by analysing additive and dominance variance components. The heritabilities were low for all health traits (between 0.033 for mastitis and 0.099 for SCS), and moderate for the milk production traits (between 0.261 for milk energy yield and 0.351 for milk yield). For all traits, the contribution of dominance variance to the phenotypic variance was low, varying between 0.018 for ovarian cysts and 0.078 for milk yield. Inbreeding depression, inferred from the SNP-based observed homozygosity, was significant only for the milk production traits. The contribution of dominance variance to the genetic variance was larger for the health traits, ranging from 0.233 for ovarian cysts to 0.551 for mastitis, encouraging further studies that aim at discovering QTLs based on their additive and dominance effects.

Scintillation light detection in the 6-m drift-length ProtoDUNE Dual Phase liquid argon TPC

DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6  ×  6  ×  6 m 3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties.

Prospects for beyond the Standard Model physics searches at the Deep Underground Neutrino Experiment: DUNE Collaboration

The Deep Underground Neutrino Experiment (DUNE) will be a powerful tool for a variety of physics topics. The high-intensity proton beams provide a large neutrino flux, sampled by a near detector system consisting of a combination of capable precision detectors, and by the massive far detector system located deep underground. This configuration sets up DUNE as a machine for discovery, as it enables opportunities not only to perform precision neutrino measurements that may uncover deviations from the present three-flavor mixing paradigm, but also to discover new particles and unveil new interactions and symmetries beyond those predicted in the Standard Model (SM). Of the many potential beyond the Standard Model (BSM) topics DUNE will probe, this paper presents a selection of studies quantifying DUNE's sensitivities to sterile neutrino mixing, heavy neutral leptons, non-standard interactions, CPT symmetry violation, Lorentz invariance violation, neutrino trident production, dark matter from both beam induced and cosmogenic sources, baryon number violation, and other new physics topics that complement those at high-energy colliders and significantly extend the present reach.

Effect of sexed semen on different production and functional traits in German Holsteins

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Calf sex had an influence on calving ease and dystocia rates.

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Sexed semen within same calf sex had only minor effects on most traits.

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Stillbirth rate for the few male calves from semen sexed for females was 30.6%.

The aim of this study was to analyze possible effects of semen type (conventional vs. female sexed) and calf sex on fertility and production traits. For this purpose, field data of German Holstein heifers in Lower Saxony were evaluated.

Sexed semen was mainly used for first insemination. 87.0% female calves were born from sexed semen, while 52.7% female calves were born from conventional semen. Heifers inseminated with sexed semen were on average 43 to 48 days younger at their first calving than heifers inseminated with conventional semen.

Calf sex had an influence on the average calving ease and the dystocia rates. Male calves showed higher calving ease scores and caused a higher risk for dystocia than female calves. The semen type had no influence on these characteristics.

Within the same calf sex, sexed semen had only minor effects on most traits, except for stillbirth rates: the stillbirth rate for male calves from female sexed semen was 30.6%, which was 2.86 times the stillbirth rate of male calves from conventional semen, possibly due to trisomies.

Sexed semen played only a minor role for production traits in first lactations.

The extrapolated 305-day milk yield was 200 kg lower for first calf heifers, which were inseminated with sexed semen compared to heifers inseminated with conventional semen. Fat and protein yield were 6 kg to 8 kg lower after use of sexed semen. Animals with female offspring from sexed semen showed higher survival rates than the other groups.

Phenotypic and genetic relationships between age at first calving, its component traits, and survival of heifers up to second calving

The aim of this study was to answer the question whether models for genetic evaluations of longevity should include a correction for age at first calving (AFC). For this purpose, phenotypic and genetic relationships between AFC, its component traits age at first insemination (AFI) and interval from first to last insemination (FLI), and survival of different periods of the first lactation (S1: 0 to 49 d, S2: 50 to 249 d, S3: 250 d to second calving) were investigated. Data of 721,919 German Holstein heifers, being inseminated for the first time during the years from 2003 to 2012, were used for the analyses. Phenotypic correlations of AFI, FLI, and AFC to S1 to S3 were negative. Mean estimated heritabilities were 0.239 (AFI), 0.007 (FLI), and 0.103 (AFC) and 0.023 (S1), 0.016 (S2), and 0.028 (S3) on the observed scale. The genetic correlation between AFI and FLI was close to zero. Genetic correlations between AFI and the survival traits were -0.08 (S1), -0.02 (S2), and -0.10 (S3); those between FLI and the survival traits were -0.14 (S1), -0.20 (S2), and -0.44 (S3); and those between AFC and the survival traits were -0.09 (S1), -0.06 (S2), and -0.20 (S3). Some of these genetic correlations were different from zero, which suggests that correcting for AFC in genetic evaluations for longevity in dairy cows might remove functional genetic variance and should be reconsidered.

Clinical impact of esophageal function tests and argon plasma coagulation in heterotopic gastric mucosa of the esophagus and extraesophageal reflux symptoms - a prospective study

BACKGROUND/AIMS

Globus, chronic cough, mucous obstruction and hoarseness are frequently interpreted and classified as manifestation of extraesophageal reflux (EER) or laryngopharyngeal reflux (LPR). Recent studies have indicated that ablation of heterotopic gastric mucosa of the proximal esophagus (HGMPE) by argon plasma coagulation (APC) significantly reduces EER/LPR symptoms.

METHODS

In a prospective study we evaluated 14 patients with HGMPE and EER/LPR symptoms by esophageal function testing (esophageal manometry, combined 24 h-pH-metry-impedance - oropharyngeal-pH measurement), standardized symptom questionnaire (visual analogue scales), and esophagealgastroduodenoscopy (EGD). The patients were stratified into 3 groups: GERD (n = 5), functional heartburn (n = 5) and non-GERD-non-functional heartburn (n = 4). Patients (n = 12) received endoscopic ablation of HGMPE by APC.

RESULTS

73 % of the patients responded to APC with a reduction of frequency and intensity of their EER/LPR symptoms. The response to APC varied between the quality of symptoms and was most frequently seen in globus, swallowing difficulty and mucous obstruction. The magnitude of symptom reduction was highest in heartburn, sore throat, and globus. The response to APC was comparable between the three groups of patients irrespective of GERD and the presence or absence of reflux symptoms. Although 50 % of the patients showed an increased Ryan Score as measured by acid reflux in the posterior oropharynx, comparison between responders and non-responders to APC showed no significant differences with regard to symptom quality, acid and non-acid reflux, LES resting pressure, esophageal motility and Ryan Score.

CONCLUSION

The study indicates that a large proportion of patients with HGMPE and EER/LPR symptoms responded to APC. However, we could not demonstrate a clinical or functional parameter that differentiated between responders and non-responders to APC or could predict the response to APC.

Prospective and randomized study to evaluate the clinical impact of cap assisted colonoscopy (CAC)

BACKGROUND

Although colonoscopy is the standard procedure in the diagnosis of colorectal neoplasia, a significant number of clinical relevant lesions may be missed even by experienced endoscopists using current technology. A transparent cap mounted at the tip of a colonoscope may be an easy way to extend the visual field during colonoscopy and may improve the detection rate of mucosal lesions.

MATERIAL AND METHODS

The significance of cap assisted (CAC) vs. conventional colonoscopy (CC) on polyp detection rate was evaluated in a prospective randomized controlled trial in 504 patients.

RESULTS

CC and CAC detected polyps in 39.3 % and 31.8, not significantly different. There was also no significant difference between CAC and CC according to age, sex, indication for colonoscopy, diverticulosis, sedation, bowel cleansing, withdrawal time, time/number of attempts to intubate the cecal walve, number, localization, size or histology of polyps,. However, the time to reach the cecal floor and the overall time of colonoscopy were significantly lower for CAC (1 minute).

CONCLUSION

CAC was without clinical impact on polyp detection rate or performance of colonoscopy.

Sedation-associated complications in endoscopy--prospective multicentre survey of 191142 patients

BACKGROUND/AIMS

Propofol sedation is applied as moderate sedation for almost all diagnostic and interventional endoscopies. Propofol sedation bears the risk of complications such as respiratory as well as cardiopulmonary insufficiency including sedation-induced death. According to recent guidelines, non-anesthesiologist-administered propofol (NAAP) should be performed by an additional person who has NAAP as their sole task.

METHODS

In a prospective multicentre survey involving 191,142 patients, clinically relevant endoscopy-associated complications were registered from 02/2010 to 01/2012.

RESULTS

The majority of propofol sedations were applied without additional persons for NAAP. Overall endoscopy-related complication rate was 0.0022 % (n = 424) and sedation-related complications 0.00 042 % (n = 82). Variability over time and between the clinics was low and not influenced by the number of endoscopies performed during the investigation period. Sedation-related death occurred in 6 patients (0.00 003 %), 50 % during emergency endoscopies. In all sedation-associated deaths the patients had ASA class 3 before endoscopy. All fatal complications occurred in the presence of an additional trained person for NAAP.

CONCLUSION

This large prospective survey shows that propofol sedation in gastrointestinal endoscopy is a safe procedure with a low potential of risk in daily routine. However, high risk patients (ASA ≥ 3) should be identified, especially before emergency endoscopies and managed by additional persons for NAAP and under intensive care surveillance.

Fructose malabsorption: how much fructose can a healthy subject tolerate?

BACKGROUND/AIMS

In a prospective study, we evaluated fructose absorption capacity in 17 healthy female volunteers aged 16-27 years.

METHODS

All volunteers underwent analysis of their daily food intake diary and standardized breath tests. The volunteers were challenged consecutively with oral intake of 50, 25 and 15 g of fructose.

RESULTS

The average daily ingestion of fructose (19.54 ± 14.95 g) was not different between volunteers with positive and negative breath tests. On day 1, 53% of subjects exhibited a significant (≥20 ppm) increase in breath hydrogen and gastrointestinal symptoms upon challenge with 50 g of fructose. Moreover, 37.5% of the volunteers with a negative breath test became positive upon a second challenge with 50 g of fructose but remained asymptomatic. On day 2, 1 of the 9 volunteers (12.5%) with a positive breath test on day 1 exhibited an asymptomatic positive breath test upon exposure to 25 and 15 g of fructose on day 3. The 8 volunteers with a negative test (25 g of fructose) remained negative after a second exposure to 25 g of fructose.

CONCLUSION

The results of this study indicate that hydrogen breath tests with fructose challenge of 50 g of fructose are inappropriate to characterize clinically significant fructose malabsorption.

Cap-assisted colonoscopy (CAC) significantly extends visualization in the right colon

BACKGROUND

Although colonoscopy is the standard procedure in the diagnosis of colorectal neoplasia, a significant number of clinically relevant lesions may be missed even by experienced endoscopists using current technology. Particular problems may occur with blind spots behind the semilunar folds and within the right colon. A transparent cap mounted at the tip of a colonoscope may be an easy way to extend the visual field during colonoscopy and may improve the detection rate of mucosal lesions. However, data in the literature are controversial and the quantity of the potential extension of visualization by a transparent cap has not been reported yet.

MATERIAL AND METHODS

The significance of cap-assisted colonoscopy (CAC) to increase visualization within different colonic segments (rectum, sigmoid colon, descending colon, transverse colon, ascending colon, cecum) was quantitatively analyzed by randomized back-to-back colonoscopies with and without cap. The investigations were performed in a colonic training model by 5 investigators. The inner colonic surface was stained by a raster of dots and the number of dots counted during colonoscopy served as a measure for the visible surface area of each segment.

RESULTS

The time to advance the colonoscope to the respective colonic segments and the overall time to reach the cecum were not significantly different between conventional and CAC. In contrast, overall withdrawal time and withdrawal times for the cecum, ascending colon, descending colon and rectum were significantly longer for CAC, but not for the transverse and sigmoid colon. Visualization of the colonic surface was significantly increased during CAC. Overall, 59.76 ± 2.70 % of the maximal countable dots were visualized without cap and 85.36 ± 9.62 % with cap. The improvement of visualization was only significant for the right colon, but not for the rectum, sigmoid or descending colon.

CONCLUSION

The finding of the present study suggests that the extension of visualization by CAC may be of particular value for the right colon.

Prospective comparison between double-balloon enteroscopy and spiral enteroscopy

BACKGROUND AND STUDY AIMS

Push enteroscopy, balloon-guided, and single- and double-balloon enteroscopy (DBE) are now well established techniques in gastrointestinal endoscopy for small-bowel imaging and therapy. There are no published prospective studies comparing DBE with spiral enteroscopy and so the aim of the current study was to compare the performance of the two techniques in patients undergoing diagnostic enteroscopy.

PATIENTS AND METHODS

Between January and December 2009, 35 patients referred for diagnostic enteroscopy were prospectively assigned to either spiral enteroscopy (n=18) or DBE (n=17). The performance of the two techniques was compared.

RESULTS

The patients were comparable with regard to age, sex, and indication for enteroscopy. Investigation performance, as assessed by time of insertion into the pylorus, the depth of insertion, the duration of the enteroscopy, and the amount of sedoanalgesia required were not significantly different between spiral enteroscopy and DBE. In 40% of the investigations, enteroscopy could detect abnormalities in the intestinal mucosa, in particular inflammatory changes and ulcers and, to a lesser extent, angiodysplasia. No significant difference in pathological findings could be detected between the two groups; however, clinically, diagnostic yield appeared to be higher for DBE (47.1% vs. 33.4%; n.s.).

CONCLUSION

Although this small study appears to show that DBE has a clinically higher diagnostic yield than spiral enteroscopy, larger studies are needed to confirm this preliminary finding.

Krefeld CONTRA study: conventional peroral Esophago-Gastro-Duodenoscopy (EGD) vs. transnasal EGD--a prospective and randomised study with independent evaluation of conscious sedation, endoscope diameter, and access path

BACKGROUND

The guidelines of the German Gastroenterology Society (Deutsche Gesellschaft für Verdauungs- und Stoffwechselkrankheiten, DGVS) demand the presence of an additional qualified person solely responsible for patient monitoring during sedated endoscopy. Transnasal esophagogastroduodenoscopy (EGD) allows easy access to the upper gastrointestinal tract and may avoid the complications induced by conscious sedation and reduce medical costs.

PATIENT AND METHOD

120 patients referred to diagnostic EGD were assigned to six groups: group 1, unsedated peroral EGD with normal-caliber endoscope; group 2, unsedated peroral EGD with small-caliber endoscope; group 3, sedated peroral EGD with normal-caliber endoscope; group 4, sedated peroral EGD with small-caliber endoscope; group 5, unsedated transnasal EGD with small-caliber endoscope; group 6, sedated transnasal EGD with small-caliber endoscope. Outcome parameters included objective (duration, oxygen saturation) and subjective measures (standardised visual analogue scales) of the endoscopy staff (handling, insertion, retroflexion, tolerability, overall assessment) and patients (pain, unpleasantness, sore throat, choking, gagging, meteorism, anxiety, acceptability).

RESULTS

The patients were comparable according to age, sex, anxiety, and respiratory function before EGD. Sedoanalgesia was without effect on EGD handling and duration, patient tolerability and overall assessment by endoscopists and assistants. Negative effects of sedoanalgesia (decreased oxygen saturation, patient acceptability) were much lower and without significance for transnasal compared to peroral EGD. Patient tolerability and acceptability of the endoscopic staff (handling, insertion, retroflexion) were significantly better for the small-caliber endoscope. Duration of unsedated transnasal EGD was slightly but significantly longer, pain, unpleasantness, and anxiety slightly but significantly higher compared to sedated peroral EGD. However, these differences could no loner be detected seven days after endoscopy. Cost analysis revealed major advantage for transnasal EGD.

CONCLUSION

Unsedated transnasal EGD may replace diagnostic peroral EGD, reduces costs with acceptable patient discomfort and has advantagous acceptability of the endoscopic staff.

Multiple colon ulcerations, perforation and death during treatment of malignant melanoma with sorafenib

BACKGROUND

Sorafenib (Nexavar) is an oral multi-kinase inhibitor with anti-angiogenic and antiproliferative effects. It has shown in-vitro and clinical activity against several kinds of tumors, such as malignant melanoma.

HISTORY, DIAGNOSIS, TREATMENT AND COURSE

A 66-year-old man with malignant melanoma was treated with sorafenib, 2 yen 400 mg per day. Because of severe diarrhea and abdominal pain, sorafenib was eventually discontinued and the patient was hospitalized for further treatment. Diagnostic work-up by upper gastrointestinal endoscopy and colonoscopy revealed multiple deep ulcerations within the whole colon. One week after admission the patient developed symptoms of acute abdomen with signs of bowel perforation requiring an emergency operation. Colectomy of the right colon with ileostomy revealed multiple (20-30) acute and subacute colonic perforations. Despite intensive care treatment the patient died of septic complications 13 days after surgery.

CONCLUSION

Treatment with anti-angiogenic multi-kinase inhibitors may be associated with gastrointestinal perforations. This has been reported for sorafenib in up to 2.3 % of cases.

Limits on a muon flux from neutralino annihilations in the sun with the IceCube 22-string detector

A search for muon neutrinos from neutralino annihilations in the Sun has been performed with the IceCube 22-string neutrino detector using data collected in 104.3 days of live time in 2007. No excess over the expected atmospheric background has been observed. Upper limits have been obtained on the annihilation rate of captured neutralinos in the Sun and converted to limits on the weakly interacting massive particle (WIMP) proton cross sections for WIMP masses in the range 250-5000 GeV. These results are the most stringent limits to date on neutralino annihilation in the Sun.

Neoadjuvant chemotherapy versus surgery alone for locally advanced adenocarcinoma of the stomach and cardia: Randomized EORTC phase III trial #40954

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Background: Combined pre- and postoperative chemotherapy improves overall survival in operable gastric cancer, although postoperative treatment is not feasible in half of the patients. We conducted a randomized phase III trial with thorough attention to preoperative staging and to the extent of surgical resection to assess the value of neoadjuvant chemotherapy (CTx). Methods: Patients with locally advanced adenocarcinoma of the stomach and cardia were randomized between primary surgery or two 48-day cycles of weekly folinic acid 500 mg/m2/2h, 5-FU 2,000 mg/m2/24h plus biweekly cisplatin 50 mg/m2/1h followed by surgery. The study was designed to detect an improvement in median survival from 17 months with surgery to 24 months with CTx plus surgery (HR=0.708, power of 80%, type I error of 4% to allow for an interim analysis). It was planned to randomize 360 patients in order to observe the 262 deaths required for the final analysis. Results: From 7/99 to 2/04, 144 patients were randomized (72:72) with comparable baseline characteristics. Median follow-up is 4.4 years. Based on 67 deaths, overall survival between the two arms did not differ (HR=0.84; 95% CI: 0.52 to 1.35; p=0.466). Median survival exceeded 36 months in both arms. Due to low accrual, this trial was stopped early. The unexpected long median survival in the surgery arm would have made the primary objective difficult to reach anyway. Based on 77 events, difference in time to progression was borderline significant (HR=0.66; 95% CI, 0.42–1.03; p=0.065). Response rate to CTx was 35.2% (95% CI: 23.7%-45.7%). The R0-resection rate was 81.9 % after CTx as compared to 66.7% with surgery alone (P=0.036). There were no major differences in intra- or postoperative complications. Conclusions: This prematurely closed trial showed a significantly increased rate of R0 resections after CTx although it could not demonstrate a survival benefit. The outcome after a radical surgical procedure alone with extended lymphadenectomy was better than expected.

No significant financial relationships to disclose.

Independent measurement of the total active 8B solar neutrino flux using an array of 3He proportional counters at the Sudbury Neutrino Observatory

The Sudbury Neutrino Observatory (SNO) used an array of 3He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active (nu_x) 8B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54_-0.31;+0.33(stat)-0.34+0.36(syst)x10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields Deltam2=7.59_-0.21;+0.19x10(-5) eV2 and theta=34.4_-1.2;+1.3 degrees. The uncertainty on the mixing angle has been reduced from SNO's previous results.

Limits on the high-energy gamma and neutrino fluxes from the SGR 1806-20 giant flare of 27 December 2004 with the AMANDA-II detector

On 27 December 2004, a giant gamma flare from the Soft Gamma-Ray Repeater 1806-20 saturated many satellite gamma-ray detectors, being the brightest transient event ever observed in the Galaxy. AMANDA-II was used to search for down-going muons indicative of high-energy gammas and/or neutrinos from this object. The data revealed no significant signal, so upper limits (at 90% C.L.) on the normalization constant were set: 0.05(0.5) TeV-1 m;{-2} s;{-1} for gamma=-1.47 (-2) in the gamma flux and 0.4(6.1) TeV-1 m;{-2} s;{-1} for gamma=-1.47 (-2) in the high-energy neutrino flux.

Relief of reflux symptoms after endoscopic gastroplication may be associated with reduced esophageal Acid sensitivity: a pilot study

BACKGROUND AND STUDY AIMS

Although the new endoscopic techniques for the treatment of gastroesophageal reflux disease (GERD) lead to marked clinical benefit, the underlying mechanism of this is unknown.

MATERIALS AND METHODS

In this prospective study, the effect of endoscopic gastroplication was investigated in six patients with GERD, who were assessed before and 4 weeks after treatment. The effect on reflux symptoms, quality of life, proton pump inhibitor (PPI) consumption, reflux esophagitis, acid exposure, esophageal motility, lower esophageal sphincter pressure (LESP), and gastric emptying was measured. Esophageal acid sensitivity before and after treatment was investigated using a standardized acid provocation test, and compared with that of six age- and sex-matched healthy controls.

RESULTS

Significant clinical benefit and discontinuation of PPI consumption after gastroplication was seen. Among the objectively measured parameters, only acid exposure was significantly reduced and gastric emptying significantly delayed. However, acid exposure remained pathologically high. Esophageal acid sensitivity was significantly reduced. The induction of heartburn and/or pain was abolished in four patients after gastroplication. In two patients the intensity of heartburn/pain was significantly reduced by 40 % or 60 %, and the time to provoke heartburn/pain significantly prolonged by 40% or 100%.

CONCLUSION

These preliminary data suggest that the decrease of esophageal sensitivity to acid after endoscopic gastroplication is part of the mechanism responsible for the reduction of reflux symptoms.

Measurement of the total active 8B solar neutrino flux at the Sudbury Neutrino Observatory with enhanced neutral current sensitivity

The Sudbury Neutrino Observatory has precisely determined the total active (nu(x)) 8B solar neutrino flux without assumptions about the energy dependence of the nu(e) survival probability. The measurements were made with dissolved NaCl in heavy water to enhance the sensitivity and signature for neutral-current interactions. The flux is found to be 5.21 +/- 0.27(stat)+/-0.38(syst) x 10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of these and other solar and reactor neutrino results yields Deltam(2)=7.1(+1.2)(-0.6) x 10(-5) eV(2) and theta=32.5(+2.4)(-2.3) degrees. Maximal mixing is rejected at the equivalent of 5.4 standard deviations.

Constraints on nucleon decay via invisible modes from the Sudbury Neutrino Observatory

Data from the Sudbury Neutrino Observatory have been used to constrain the lifetime for nucleon decay to "invisible" modes, such as n-->3nu. The analysis was based on a search for gamma rays from the deexcitation of the residual nucleus that would result from the disappearance of either a proton or neutron from 16O. A limit of tau(inv)>2 x 10(29) yr is obtained at 90% confidence for either neutron- or proton-decay modes. This is about an order of magnitude more stringent than previous constraints on invisible proton-decay modes and 400 times more stringent than similar neutron modes.

Measurement of day and night neutrino energy spectra at SNO and constraints on neutrino mixing parameters

The Sudbury Neutrino Observatory (SNO) has measured day and night solar neutrino energy spectra and rates. For charged current events, assuming an undistorted 8B spectrum, the night minus day rate is 14.0%+/-6.3%(+1.5%)(-1.4%) of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the nu(e) asymmetry is found to be 7.0%+/-4.9%(+1.3%)(-1.2%). A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the large mixing angle solution.

Direct evidence for neutrino flavor transformation from neutral-current interactions in the Sudbury Neutrino Observatory

Observations of neutral-current nu interactions on deuterium in the Sudbury Neutrino Observatory are reported. Using the neutral current (NC), elastic scattering, and charged current reactions and assuming the standard 8B shape, the nu(e) component of the 8B solar flux is phis(e) = 1.76(+0.05)(-0.05)(stat)(+0.09)(-0.09)(syst) x 10(6) cm(-2) s(-1) for a kinetic energy threshold of 5 MeV. The non-nu(e) component is phi(mu)(tau) = 3.41(+0.45)(-0.45)(stat)(+0.48)(-0.45)(syst) x 10(6) cm(-2) s(-1), 5.3sigma greater than zero, providing strong evidence for solar nu(e) flavor transformation. The total flux measured with the NC reaction is phi(NC) = 5.09(+0.44)(-0.43)(stat)(+0.46)(-0.43)(syst) x 10(6) cm(-2) s(-1), consistent with solar models.

Measurement of the rate of nu(e) + d --> p + p + e(-) interactions produced by (8)B solar neutrinos at the Sudbury Neutrino Observatory

Solar neutrinos from (8)B decay have been detected at the Sudbury Neutrino Observatory via the charged current (CC) reaction on deuterium and the elastic scattering (ES) of electrons. The flux of nu(e)'s is measured by the CC reaction rate to be straight phi(CC)(nu(e)) = 1.75 +/- 0.07(stat)(+0.12)(-0.11)(syst) +/- 0.05(theor) x 10(6) cm(-2) s(-1). Comparison of straight phi(CC)(nu(e)) to the Super-Kamiokande Collaboration's precision value of the flux inferred from the ES reaction yields a 3.3 sigma difference, assuming the systematic uncertainties are normally distributed, providing evidence of an active non- nu(e) component in the solar flux. The total flux of active 8B neutrinos is determined to be 5.44+/-0.99 x 10(6) cm(-2) s(-1).

Observation of X-ray lines from a gamma-ray burst (GRB991216): evidence of moving ejecta from the progenitor

We report on the discovery of two emission features observed in the x-ray spectrum of the afterglow of the gamma-ray burst (GRB) of 16 December 1999 by the Chandra X-ray Observatory. These features are identified with the Ly(alpha) line and the narrow recombination continuum by hydrogenic ions of iron at a redshift z = 1.00 +/- 0.02, providing an unambiguous measurement of the distance of a GRB. Line width and intensity imply that the progenitor of the GRB was a massive star system that ejected, before the GRB event, a quantity of iron approximately 0.01 of the mass of the sun at a velocity approximately 0.1 of the speed of light, probably by a supernova explosion.

Discovery of a transient absorption edge in the X-ray spectrum of GRB 990705

We report the discovery of a transient equivalent hydrogen column density with an absorption edge at approximately 3.8 kiloelectron volts in the spectrum of the prompt x-ray emission of gamma-ray burst (GRB) 990705. This feature can be satisfactorily modeled with a photoelectric absorption by a medium located at a redshift of approximately 0.86 and with an iron abundance of approximately 75 times the solar one. The transient behavior is attributed to the strong ionization produced in the circumburst medium by the GRB photons. The high iron abundance points to the existence of a burst environment enriched by a supernova along the line of sight. The supernova explosion is estimated to have occurred about 10 years before the burst. Our results agree with models in which GRBs originate from the collapse of very massive stars and are preceded by a supernova event.

X-Ray Spectral Diagnostics of Gamma-Ray Burst Environments

Recently, detection of discrete features in the X-ray afterglow spectra of GRB 970508 and GRB 970828 was reported. The most natural interpretation of these features is that they are redshifted Fe K emission complexes. The identification of the line emission mechanism has drastic implications for the inferred mass of radiating material and hence the nature of the burst site. X-ray spectroscopy provides a direct observational constraint on these properties of gamma-ray bursters. We briefly discuss how these constraints arise in the context of an application to the spectrum of GRB 970508.

Prompt Optical Observations of Gamma-Ray Bursts

The Robotic Optical Transient Search Experiment (ROTSE) seeks to measure simultaneous and early afterglow optical emission from gamma-ray bursts (GRBs). A search for optical counterparts to six GRBs with localization errors of 1 deg2 or better produced no detections. The earliest limiting sensitivity is mROTSE>13.1 at 10.85 s (5 s exposure) after the gamma-ray rise, and the best limit is mROTSE>16.0 at 62 minutes (897 s exposure). These are the most stringent limits obtained for the GRB optical counterpart brightness in the first hour after the burst. Consideration of the gamma-ray fluence and peak flux for these bursts and for GRB 990123 indicates that there is not a strong positive correlation between optical flux and gamma-ray emission.

Decay of the GRB 990123 optical afterglow: implications for the fireball model

Broad-band (ultraviolet to near-infrared) observations of the intense gamma ray burst GRB 990123 started approximately 8.5 hours after the event and continued until 18 February 1999. When combined with other data, in particular from the Robotic Telescope and Transient Source Experiment (ROTSE) and the Hubble Space Telescope (HST), evidence emerges for a smoothly declining light curve, suggesting some color dependence that could be related to a cooling break passing the ultraviolet-optical band at about 1 day after the high-energy event. The steeper decline rate seen after 1.5 to 2 days may be evidence for a collimated jet pointing toward the observer.