Factors influencing in-hospital mortality for salvage percutaneous transjugular intrahepatic portosystemic shunting in cirrhotic patients with recalcitrant variceal bleeding after failed endoscopic intervention

BACKGROUND

Endoscopic therapy is the first-line treatment of choice for control of acute variceal bleeding (AVB). In high-risk patients with persistent AVB despite pharmacological treatment and endoscopic intervention, percutaneous transjugular intrahepatic portosystemic shunting (TIPS) provides a minimally invasive salvage method to reduce portal pressure and control bleeding.

OBJECTIVES

To evaluate factors influencing in-hospital mortality after salvage TIPS (sTIPS) in patients with exsanguinating variceal bleeding despite medical treatment and endoscopic intervention.

METHODS

Clinical and laboratory data were analysed in all patients treated with sTIPS following failed endoscopic therapy for AVB between August 1991 and November 2020. Factors associated with and predictors of death were determined using bivariate analysis and univariate logistic regression analysis.

RESULTS

Thirty-four patients (29 men, 5 women), mean age 52 years (range 31 - 80), received sTIPS for uncontrolled (n=11) or refractory (n=23) AVB. The causes of portal hypertension were alcohol-related (n=24) and non-alcohol-related cirrhosis. Salvage TIPS controlled bleeding in 32 patients, with recurrence in 1. Ten patients died in hospital (mean 4.8 days, range 1 - 10) of liver failure (n=4), multiorgan failure (n=3), alcoholic cardiomyopathy (n=2) and uncontrolled gastric variceal bleeding (n=1). On bivariate analysis, factors associated with death were Child-Pugh (C-P) score ≥10 (p=0.006), sodium Model for End-stage Liver Disease (MELD-Na) score ≥22 (p<0.001), ≥8 units of blood transfused (p<0.001), Sengstaken-Blakemore balloon tube placement (p<0.001), endotracheal intubation (p<0.001), inotropic support (p<0.001) and endoscopically uncontrolled bleeding (p<0.001). Univariate logistic regression analysis showed that the most significant predictors of mortality were inotrope dependency (odds ratio (OR) 134; p<0.001), endotracheal intubation (OR 99; p<0.001), endoscopically uncontrolled bleeding (OR 28; p=0.001), grade 3 ascites (OR 20.9; p=0.012) and C-P grade C (OR 8.8; p=0.011).

CONCLUSION

Salvage TIPS controlled variceal bleeding in 94% of patients after failed endoscopic therapy with 29% in-hospital mortality. The most significant predictors of mortality were C-P grade C, grade 3 ascites, inotrope requirement, endotracheal intubation and endoscopically uncontrolled bleeding.

Active radiation measurements over one solar cycle with two DOSTEL instruments in the Columbus laboratory of the International Space Station

Two DOSimetry TELescopes (DOSTELs) have been measuring the radiation environment in the Columbus module of the International Space Station (ISS) since 2009 in the frame of the DOSIS and DOSIS 3D projects. Both instruments have measured the charged particle flux rate and dose rates in a telescope geometry of two planar silicon detectors. The radiation environment in the ISS orbit is mostly composed by galactic cosmic radiation (GCR) and its secondary radiation and protons from the inner radiation belt in the South Atlantic Anomaly (SAA) with sporadic contributions of solar energetic particles at high latitudes. The data presented in this work cover two solar activity minima and corresponding GCR intensity maxima in 2009 and 2020 and the solar activity maximum and corresponding GCR intensity minimum in 2014/2015. Average dose rates measured in the Columbus laboratory in the ISS orbit from GCR and SAA are presented separately. The data is analyzed with respect to the effective magnetic shielding and grouped into different cut-off rigidity intervals. Using only measurements in magnetically unshielded regions at low cut-off rigidity and applying a factor for the geometrical shielding of the Earth, absorbed dose rates and dose equivalent rates in near-Earth interplanetary space are estimated for the years 2009 to 2022.

Temporal Structures in Electron Spectra and Charge Sign Effects in Galactic Cosmic Rays

We present the precision measurements of 11 years of daily cosmic electron fluxes in the rigidity interval from 1.00 to 41.9 GV based on 2.0×10^{8} electrons collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. The electron fluxes exhibit variations on multiple timescales. Recurrent electron flux variations with periods of 27 days, 13.5 days, and 9 days are observed. We find that the electron fluxes show distinctly different time variations from the proton fluxes. Remarkably, a hysteresis between the electron flux and the proton flux is observed with a significance of greater than 6σ at rigidities below 8.5 GV. Furthermore, significant structures in the electron-proton hysteresis are observed corresponding to sharp structures in both fluxes. This continuous daily electron data provide unique input to the understanding of the charge sign dependence of cosmic rays over an 11-year solar cycle.

Properties of Daily Helium Fluxes

We present the precision measurement of 2824 daily helium fluxes in cosmic rays from May 20, 2011 to October 29, 2019 in the rigidity interval from 1.71 to 100 GV based on 7.6×10^{8} helium nuclei collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. The helium flux and the helium to proton flux ratio exhibit variations on multiple timescales. In nearly all the time intervals from 2014 to 2018, we observed recurrent helium flux variations with a period of 27 days. Shorter periods of 9 days and 13.5 days are observed in 2016. The strength of all three periodicities changes with time and rigidity. In the entire time period, we found that below ∼7  GV the helium flux exhibits larger time variations than the proton flux, and above ∼7  GV the helium to proton flux ratio is time independent. Remarkably, below 2.4 GV a hysteresis between the helium to proton flux ratio and the helium flux was observed at greater than the 7σ level. This shows that at low rigidity the modulation of the helium to proton flux ratio is different before and after the solar maximum in 2014.

Periodicities in the Daily Proton Fluxes from 2011 to 2019 Measured by the Alpha Magnetic Spectrometer on the International Space Station from 1 to 100 GV

We present the precision measurement of the daily proton fluxes in cosmic rays from May 20, 2011 to October 29, 2019 (a total of 2824 days or 114 Bartels rotations) in the rigidity interval from 1 to 100 GV based on 5.5×10^{9} protons collected with the Alpha Magnetic Spectrometer aboard the International Space Station. The proton fluxes exhibit variations on multiple timescales. From 2014 to 2018, we observed recurrent flux variations with a period of 27 days. Shorter periods of 9 days and 13.5 days are observed in 2016. The strength of all three periodicities changes with time and rigidity. The rigidity dependence of the 27-day periodicity is different from the rigidity dependences of 9-day and 13.5-day periods. Unexpectedly, the strength of 9-day and 13.5-day periodicities increases with increasing rigidities up to ∼10  GV and ∼20  GV, respectively. Then the strength of the periodicities decreases with increasing rigidity up to 100 GV.

Erratum: Properties of a New Group of Cosmic Nuclei: Results from the Alpha Magnetic Spectrometer on Sodium, Aluminum, and Nitrogen [Phys. Rev. Lett. 127, 021101 (2021)]

This corrects the article DOI: 10.1103/PhysRevLett.127.021101.

Properties of a New Group of Cosmic Nuclei: Results from the Alpha Magnetic Spectrometer on Sodium, Aluminum, and Nitrogen

We report the properties of sodium (Na) and aluminum (Al) cosmic rays in the rigidity range 2.15 GV to 3.0 TV based on 0.46 million sodium and 0.51 million aluminum nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. We found that Na and Al, together with nitrogen (N), belong to a distinct cosmic ray group. In this group, we observe that, similar to the N flux, both the Na flux and Al flux are well described by the sums of a primary cosmic ray component (proportional to the silicon flux) and a secondary cosmic ray component (proportional to the fluorine flux). The fraction of the primary component increases with rigidity for the N, Na, and Al fluxes and becomes dominant at the highest rigidities. The Na/Si and Al/Si abundance ratios at the source, 0.036±0.003 for Na/Si and 0.103±0.004 for Al/Si, are determined independent of cosmic ray propagation.

Properties of Heavy Secondary Fluorine Cosmic Rays: Results from the Alpha Magnetic Spectrometer

Precise knowledge of the charge and rigidity dependence of the secondary cosmic ray fluxes and the secondary-to-primary flux ratios is essential in the understanding of cosmic ray propagation. We report the properties of heavy secondary cosmic ray fluorine F in the rigidity R range 2.15 GV to 2.9 TV based on 0.29 million events collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The fluorine spectrum deviates from a single power law above 200 GV. The heavier secondary-to-primary F/Si flux ratio rigidity dependence is distinctly different from the lighter B/O (or B/C) rigidity dependence. In particular, above 10 GV, the F/Si/B/O ratio can be described by a power law R^{δ} with δ=0.052±0.007. This shows that the propagation properties of heavy cosmic rays, from F to Si, are different from those of light cosmic rays, from He to O, and that the secondary cosmic rays have two classes.

Properties of Iron Primary Cosmic Rays: Results from the Alpha Magnetic Spectrometer

We report the observation of new properties of primary iron (Fe) cosmic rays in the rigidity range 2.65 GV to 3.0 TV with 0.62×10^{6} iron nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. Above 80.5 GV the rigidity dependence of the cosmic ray Fe flux is identical to the rigidity dependence of the primary cosmic ray He, C, and O fluxes, with the Fe/O flux ratio being constant at 0.155±0.006. This shows that unexpectedly Fe and He, C, and O belong to the same class of primary cosmic rays which is different from the primary cosmic rays Ne, Mg, and Si class.

First measurements of the radiation dose on the lunar surface

Human exploration of the Moon is associated with substantial risks to astronauts from space radiation. On the surface of the Moon, this consists of the chronic exposure to galactic cosmic rays and sporadic solar particle events. The interaction of this radiation field with the lunar soil leads to a third component that consists of neutral particles, i.e., neutrons and gamma radiation. The Lunar Lander Neutrons and Dosimetry experiment aboard China's Chang'E 4 lander has made the first ever measurements of the radiation exposure to both charged and neutral particles on the lunar surface. We measured an average total absorbed dose rate in silicon of 13.2 ± 1 μGy/hour and a neutral particle dose rate of 3.1 ± 0.5 μGy/hour.

Properties of Neon, Magnesium, and Silicon Primary Cosmic Rays Results from the Alpha Magnetic Spectrometer

We report the observation of new properties of primary cosmic rays, neon (Ne), magnesium (Mg), and silicon (Si), measured in the rigidity range 2.15 GV to 3.0 TV with 1.8×10^{6}  Ne, 2.2×10^{6}  Mg, and 1.6×10^{6}  Si nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The Ne and Mg spectra have identical rigidity dependence above 3.65 GV. The three spectra have identical rigidity dependence above 86.5 GV, deviate from a single power law above 200 GV, and harden in an identical way. Unexpectedly, above 86.5 GV the rigidity dependence of primary cosmic rays Ne, Mg, and Si spectra is different from the rigidity dependence of primary cosmic rays He, C, and O. This shows that the Ne, Mg, and Si and He, C, and O are two different classes of primary cosmic rays.

Resection of biliary mucinous cystic neoplasms of the liver: a prospective cohort series of 13 consecutive patients

BACKGROUND

Biliary mucinous cystic neoplasms (BMCNs) are uncommon neoplastic septated intrahepatic cysts which are often incorrectly diagnosed and have the potential for malignant transformation.

OBJECTIVE

To assess the outcome of surgical resection of BMCNs.

METHOD

A prospective liver surgery database was used to identify patients who underwent surgery at Groote Schuur Hospital Complex for BMCN from 1999 to 2015. Demographic variables including age and gender were documented as well as detailed preoperative imaging, location and size, operative treatment, extent of resection, histology, postoperative complications and outcome.

RESULTS

Thirteen female patients (median age 45 years) had surgery. Eleven were diagnosed by imaging for symptoms. Two were jaundiced. One cyst was found during an elective cholecystectomy. Five cysts were located centrally in the liver. Before referral three cysts were treated with percutaneous drainage and two were treated with operative deroofing. Six patients had anatomical liver resections and seven patients had non anatomical liver resections of which two needed ablation of residual cyst wall. One patient needed a biliary-enteric reconstruction to treat a fistula. Median operative time was 183 minutes (range: 130-375). No invasive carcinoma was found. There was no operative mortality. One surgical site infection and one intra-abdominal collection were treated. Two patients developed recurrent BMCN after 24 months.

CONCLUSION

BMCNs should be considered in middle aged women who have well encapsulated multilocular liver cysts. Treatment of large central BMCNs adjacent to vascular and biliary structures may require technically complex liver resections and are best managed in a specialised hepato-pancreatico-biliary unit.

Distal malignant biliary obstruction: a prospective randomised trial comparing plastic and uncovered self-expanding metal stents in the palliation of symptomatic jaundice

BACKGROUND

The aim of this study was to determine the safety and clinical effectiveness of 10Fr plastic biliary stents compared to uncovered self-expanding metal stents (SEMS) for palliative treatment of patients with inoperable extra-hepatic malignant biliary obstruction in a public hospital in South Africa.

METHOD

From January 2009 to December 2013, 40 patients who were admitted to a tertiary academic centre because of distal malignant biliary obstruction were enrolled in a prospective randomized study. Patients were randomly assigned to receive an uncovered SEMS or a plastic stent deployed through the biliary stricture during endoscopic retrograde cholangiopancreatography (ERCP).

RESULTS

Patient survival time in the two groups did not differ significantly (median: SEMS - 114 days; plastic - 107 days). Stent failure was more common in the plastic stent group (7/19 vs. 1/21). The results became significant after 6 months of follow-up. There was no significant difference between the two groups in the incidence of serious adverse events.

CONCLUSION

SEMS had a longer duration of patency than plastic stents, which recommends their use in the palliative treatment of patients with biliary obstruction due to distal malignant biliary obstruction.

Resection of benign liver tumours: an analysis of 62 consecutive cases treated in an academic referral centre

BACKGROUND

Benign tumours of the liver are increasingly diagnosed and constitute a substantial proportion of all hepatic tumours evaluated and resected at tertiary referral centres. This study assessed the safety and outcome after resection of benign liver tumours at a major referral centre.

METHOD

All patients with symptomatic benign liver tumours who underwent resection were identified from a prospective departmental database of a total of 474 liver resections (LRs). Demographic data, operative management and morbidity and mortality using the Accordion classification were analysed.

RESULTS

Sixty-two patients (56 women, 6 men, median age 45 years, range 17-82) underwent resection of symptomatic haemangiomata n=23 (37.1%), focal nodular hyperplasia n=19 (30.6%), biliary cystadenoma n=16 (25.8%) and hepatic adenomas n=4 (6.5%). A major resection was required in 25 patients, 14 patients had 4 segments resected, 11 had 3 segments and 37 patients had 2 or fewer segments resected. Median operating time was 169 minutes (range 80-410). Median blood loss was 300 ml (range 50-4500 ml) and an intra-operative blood transfusion was required in 6 patients. Median length of post-operative hospital stay was 7 days (range 4-32). Complications occurred in 11 patients (Accordion grades 1 n=1, 2 n=4, 3 n=1, 4 n=4, 6 n=1). Four patients required re-operation (bleeding n=2, bile leak n=1, small bowel obstruction n=1). An elderly patient died in hospital on day 16 following a postoperative cerebrovascular accident.

CONCLUSION

Clinically relevant symptomatic benign liver tumours comprise a substantial proportion of LRs. Our data suggest that resections can be performed safely with minimal blood loss and transfusion requirements. We advocate selective resection according to established indications. Despite the low postoperative mortality rate, the risk of postoperative complications emphasizes the need for careful selection of patients for resection.

The charged particle radiation environment on Mars measured by MSL/RAD from November 15, 2015 to January 15, 2016

The Radiation Assessment Detector (RAD) on board the Mars Science Laboratory (MSL) Curiosity rover has been measuring the radiation environment in Gale crater on Mars since August, 2012. These first in-situ measurements provide an important data set for assessing the radiation-associated health risks for future manned missions to Mars. Mainly, the radiation field on the Martian surface stems from Galactic Cosmic Rays (GCRs) and secondary particles created by the GCRs' interactions with the Martian atmosphere and soil. RAD is capable of measuring differential particle fluxes for lower-energy ions and isotopes of hydrogen and helium (up to hundreds of MeV/nuc). Additionally, RAD also measures integral particle fluxes for higher energies of these ions. Besides providing insight on the current Martian radiation environment, these fluxes also present an essential input for particle transport codes that are used to model the radiation to be encountered during future manned missions to Mars. Comparing simulation results with actual ground-truth measurements helps to validate these transport codes and identify potential areas of improvements in the underlying physics of these codes. At the First Mars Radiation Modeling Workshop (June 2016 in Boulder, CO), different groups of modelers were asked to calculate the Martian surface radiation environment for the time of November 15, 2015 to January 15, 2016. These model results can then be compared with in-situ measurements of MSL/RAD conducted during the same time frame. In this publication, we focus on presenting the charged particle fluxes measured by RAD between November 15, 2015 and January 15, 2016, providing the necessary data set for the comparison to model outputs from the modeling workshop. We also compare the fluxes to initial GCR intensities, as well as to RAD measurements from an earlier time period (August 2012 to January 2013). Furthermore, we describe how changes and updates in RAD on board processing and the on ground analysis tools effect and improve the flux calculations. An in-depth comparison of modeling results from the workshop and RAD fluxes of this publication is presented elsewhere in this issue (Matthiä et al., 2017).

Incidence and management of postoperative bile leaks: A prospective cohort analysis of 467 liver resections

BACKGROUND

Bile leaks from the parenchymal transection margin are a major cause of morbidity following major liver resections. The aim of this study was to benchmark the incidence and identify the risk factors for postoperative bile leakage after hepatic resection.

PATIENTS AND METHODS

A prospective database of 467 consecutive liver resections performed by the University of Cape Town HPB surgical unit between January 1990 and January 2016 was analysed. The relationship of demographic, clinical and perioperative factors to the development of bile leakage was determined. Bile leak and postoperative complications severity were graded using the International Study Group of Liver Surgery and Accordion classifications.

RESULTS

Overall morbidity was 24% (n = 112), with bile leaks occurring in 25 (5.4%) patients. Significantly more bile leaks occurred in patients who had major resections (≥ 3 segments) and longer total operative times (p < 0.05). There were 5 Grade A bile leaks which stopped spontaneously. Seventeen Grade B leaks required a combination of percutaneous drainage (n = 15), endoscopic biliary stenting (n = 8) and percutaneous transhepatic biliary drainage (n = 3). All 3 Grade C leaks required laparotomy for definitive drainage. Median hospital stay in the 442 patients without a bile leak was 8 days (IQR 1-98) compared with 12 days (IQR 6-30) for the 25 with bile leaks (p < 0.05) with no mortality. Major resections (≥ 3 segments) and total operative time (> 180mins) were significantly associated with bile leaks.

CONCLUSION

The incidence of bile leakage was 5.4% and occurred after major liver resections with longer operative times and resulted in significantly extended hospitalisation. Most were effectively treated nonoperatively by percutaneous drainage of the collection and/or endoscopic or percutaneous biliary drainage without mortality.

Severe post-pancreatoduodenectomy haemorrhage: An analytical review based on 118 consecutive pancreatoduodenectomy patients in a South African Academic Hospital

BACKGROUND

Bleeding after a major pancreatic resection, although uncommon, has serious implications and substantial mortality rates.

AIM

To analyse our experience with severe post-pancreatoduodenectomy haemorrhage (PPH) over the last 7 years to establish the incidence, causes, intervention required and outcome.

METHOD

All patients who underwent a pancreatoduodenectomy (PD) between January 2008 and December 2015 were identified from a prospectively maintained database. Data analysed included demographic information, operative details, anastomotic technique, histology, postoperative complications including pancreatic fistula and PPH, length of hospital stay, need for blood products and special investigations. Pancreatic fistula was classified according to the International Study Group of Pancreatic Surgery (ISGPS) classification. A modified ISGPS classification was used for PPH.

RESULTS

One hundred and eighteen patients underwent PD during the study period of whom 6 (5.0%) died perioperatively. Twenty patients (16.9%) developed a pancreatic fistula and 11 patients (9.3%) had a severe PPH of whom one (9.1%) died. No patients had a severe bleed during the first 24 hours postoperatively. Four patients bled within the first 5 days and the remaining 7 after five days. Six patients bled from the gastroduodenal artery and were all preceded by a pancreatic fistula. Three of the 7 patients who bled late presented with extraluminal bleeding, 3 presented with intraluminal bleeding and 1 with a combination of both. Patients presenting in the first 5 days were all successfully managed either endoscopically or surgically. Five patients who presented beyond 5 days postoperatively were managed primarily with interventional angiography, either with coiling or deployment of a covered stent. Three patients who had radiological intervention developed a liver abscess or necrosis.

CONCLUSION

Severe PPH is associated with substantial morbidity. Clinical factors including the onset of the bleeding, presentation with either extra and/or intraluminal haemorrhage, and the presence of a pancreatic fistula give an indication of the likely aetiology of the bleeding. A management algorithm based on these factors is presented.

Primary seromucinous cystadenocarcinoma of the mesentery

A 72-year-old woman presented with a slow growing mass on the left side of the abdomen, which was found to originate from the mesentery of the descending colon. Histopathology revealed a seromucinous cystadenocarcinoma of the mesentery, a rare clinical entity occurring most often in females. There are only 20 cases reported in the literature. It is postulated that these tumours develop as a result of serous or mucinous metaplasia of pre-existing coelomic mesothelium. Surgical excision remains the mainstay of successful management.

Charged particle spectra measured during the transit to Mars with the Mars Science Laboratory Radiation Assessment Detector (MSL/RAD)

The Mars Science Laboratory (MSL) started its 253-day cruise to Mars on November 26, 2011. During cruise the Radiation Assessment Detector (RAD), situated on board the Curiosity rover, conducted measurements of the energetic-particle radiation environment inside the spacecraft. This environment consists mainly of galactic cosmic rays (GCRs), as well as secondary particles created by interactions of these GCRs with the spacecraft. The RAD measurements can serve as a proxy for the radiation environment a human crew would encounter during a transit to Mars, for a given part of the solar cycle, assuming that a crewed vehicle would have comparable shielding. The measurements of radiological quantities made by RAD are important in themselves, and, the same data set allow for detailed analysis of GCR-induced particle spectra inside the spacecraft. This provides important inputs for the evaluation of current transport models used to model the free-space (and spacecraft) radiation environment for different spacecraft shielding and different times in the solar cycle. Changes in these conditions can lead to significantly different radiation fields and, thus, potential health risks, emphasizing the need for validated transport codes. Here, we present the first measurements of charged particle fluxes inside a spacecraft during the transit from Earth to Mars. Using data obtained during the last two month of the cruise to Mars (June 11-July 14, 2012), we have derived detailed energy spectra for low-Z particles stopping in the instrument's detectors, as well as integral fluxes for penetrating particles with higher energies. Furthermore, we analyze the temporal changes in measured proton fluxes during quiet solar periods (i.e., when no solar energetic particle events occurred) over the duration of the transit (December 9, 2011-July 14, 2012) and correlate them with changing heliospheric conditions.

MSL-RAD radiation environment measurements

In this study, results are presented from the on-board radiation assessment detector (RAD) of Mars Science Laboratory (MSL). RAD is designed to measure the energetic particle radiation environment, which consists of galactic cosmic rays (GCRs) and solar energetic particles (SEPs) as well as secondary particles created by nuclear interactions of primary particles in the shielding (during cruise) or Martian soil and atmosphere (surface measurements). During the cruise, RAD collected data on space radiation from inside the craft, thus allowing for a reasonable estimation of what a human crew travelling to/from Mars might be exposed to. On the surface of Mars, RAD is shielded by the atmosphere (from above) and the planet itself (from below). RAD measures the first detailed radiation data from the surface of another planet, and they are highly relevant for planning future crewed missions. The results for radiation dose and dose equivalent (a quantity most directly related to human health risk) are presented during the cruise phase, as well as on the Martian surface. Dose and dose equivalent are dominated by the continuous GCR radiation, but several SEP events were also detected and are discussed here.

Measurements of the neutron spectrum in transit to Mars on the Mars Science Laboratory

The Mars Science Laboratory spacecraft, containing the Curiosity rover, was launched to Mars on 26 November 2011. Although designed for measuring the radiation on the surface of Mars, the Radiation Assessment Detector (RAD) measured the radiation environment inside the spacecraft during most of the 253-day, 560-million-kilometer cruise to Mars. An important factor for determining the biological impact of the radiation environment inside the spacecraft is the specific contribution of neutrons with their high biological effectiveness. We apply an inversion method (based on a maximum-likelihood estimation) to calculate the neutron and gamma spectra from the RAD neutral particle measurements. The measured neutron spectrum (12-436 MeV) translates into a radiation dose rate of 3.8±1.2 μGy/day and a dose equivalent of 19±5 μSv/day. Extrapolating the measured spectrum (0.1-1000 MeV), we find that the total neutron-induced dose rate is 6±2 μGy/day and the dose equivalent rate is 30±10 μSv/day. For a 360 day round-trip from Earth to Mars with comparable shielding, this translates into a neutron induced dose equivalent of about 11±4 mSv.

Measurements of energetic particle radiation in transit to Mars on the Mars Science Laboratory

The Mars Science Laboratory spacecraft, containing the Curiosity rover, was launched to Mars on 26 November 2011, and for most of the 253-day, 560-million-kilometer cruise to Mars, the Radiation Assessment Detector made detailed measurements of the energetic particle radiation environment inside the spacecraft. These data provide insights into the radiation hazards that would be associated with a human mission to Mars. We report measurements of the radiation dose, dose equivalent, and linear energy transfer spectra. The dose equivalent for even the shortest round-trip with current propulsion systems and comparable shielding is found to be 0.66 ± 0.12 sievert.

Field calibration of dosemeters used for routine measurements at flight altitudes

Intercomparisons of dosemeters used in radiation protection are performed routinely in reference radiation fields under well-defined conditions. In the case of the radiation protection of aircrew members, such reference fields either do not exist or they can be partially simulated by accelerator-based fields. Another method is to perform simultaneous measurements on board an aircraft under constant flight conditions, i.e. at defined latitude, longitude and altitude. The intercomparison presented in this work is the second one of its kind. As reference instruments, two types of tissue-equivalent proportional counters (TEPC) were used in comparison with different silicon detector systems. The excellent agreement of the FDOScalc code, which is based on measurements made by PTB during different phases of solar cycle 23 with the TEPC measurements and the results of the preceding project "Coordinated Access to Aircraft for Transnational Environmental Research" (CAATER) even allows the in-field calibration of the Si dosemeters.

A double-blind placebo-controlled study of the effects of Lactobacillus acidophilus on plasma lipids

OBJECTIVE

To select a probiotic bacteria that would reduce serum lipids in hypercholesterolaemic volunteers.

DESIGN

A strain of lactobacillus was selected for its ability to metabolise cholesterol under varying conditions in vitro. Freeze-dried Lactobacillus acidophilus or placebo were then given in a double-blind randomised crossover study to volunteers with high cholesterols.

SUBJECTS

A total of 80 volunteers with elevated cholesterols.

INTERVENTIONS

Volunteers were randomly allocated to receive either two capsules containing freeze-dried L. acidophilus 3 x 10(10) CFU or placebo three times a day for 6 weeks. After a 6-week washout period, volunteers were crossed over to another 6 weeks of capsules. Serum lipids were measured at the beginning and end of each interventional period.

RESULTS

L. acidophilus was able to reduce cholesterol and survive in an acid and bile environment. No changes in anthropomorphic measurements or in dietary records were seen between the baseline and final records or between the two sets of baseline records. There were no changes in serum lipids seen throughout the study.

CONCLUSION

Despite the ability in vitro for L. acidophilus to reduce cholesterol, no effect was seen in volunteers.

Failure of dietary oligofructose to prevent antibiotic-associated diarrhoea

BACKGROUND

Oligofructose is metabolized by bifidobacteria, increasing their numbers in the colon. High bifidobacteria concentrations are important in providing 'colonization resistance' against pathogenic bacteria.

AIM

To reduce the incidence of antibiotic-associated diarrhoea in elderly patients.

METHODS

Patients over the age of 65 taking broad-spectrum antibiotics received either oligofructose or placebo. A baseline stool sample was cultured for Clostridium difficile and tested for C. difficile toxin. A further stool sample was analysed for C. difficile if diarrhoea developed.

RESULTS

No difference was seen in the baseline characteristics, incidence of diarrhoea, C. difficile infection or hospital stay between the two groups (n = 435). Oligofructose increased bifidobacterial concentrations (P < 0.001, 95% CI: 0.69-1.72). A total of 116 (27%) patients developed diarrhoea of which 49 (11%) were C. difficile-positive and were more likely to be taking a cephalosporin (P = 0.006), be female (P < 0.001), to have lost more weight (P < 0.001, 95% CI: 0.99-2.00) and stayed longer in hospital (P < 0.001, 95% CI: 0.10-1.40). Amoxicillin (amoxycillin) and clavulanic acid increased diarrhoea not caused by C. difficile (P = 0.006).

CONCLUSION

Oligofructose does not protect elderly patients receiving broad-spectrum antibiotics from antibiotic-associated diarrhoea whether caused by C. difficile or not. Oligofructose was well-tolerated and increased faecal bifidobacterial concentrations.

Radiation exposure measurement onboard civil aircraft

The active dosemeter DOSTEL based on two silicon planar detectors was flown on civil aircraft flights to study the radiation exposure of air crew members. The altitude and latitude dependence of count and dose rates as well as long-term variations are measured. After calibration of the DOSTEL response against measurements of a TEPC instrument, total dose-equivalent values for various flights are compared with H*(10) calculations by EPCARD yielding a ratio of 1.02 +/- 0.09 (standard variation).

Space radiation measurements on-board ISS--the DOSMAP experiment

The experiment 'Dosimetric Mapping' conducted as part of the science program of NASA's Human Research Facility (HRF) between March and August 2001 was designed to measure integrated total absorbed doses (ionising radiation and neutrons), heavy ion fluxes and its energy, mass and linear energy transfer (LET) spectra, time-dependent count rates of charged particles and their corresponding dose rates at different locations inside the US Lab at the International Space Station. Owing to the variety of particles and energies, a dosimetry package consisting of thermoluminescence dosemeter (TLD) chips and nuclear track detectors with and without converters (NTDPs), a silicon dosimetry telescope (DOSTEL), four mobile silicon detector units (MDUs) and a TLD reader unit (PILLE) with 12 TLD bulbs as dosemeters was used. Dose rates of the ionising part of the radiation field measured with TLD bulbs applying the PILLE readout system at different locations varied between 153 and 231 microGy d(-1). The dose rate received by the active devices fits excellent to the TLD measurements and is significantly lower compared with measurements for the Shuttle (STS) to MIR missions. The comparison of the absorbed doses from passive and active devices showed an agreement within +/- 10%. The DOSTEL measurements in the HRF location yielded a mean dose equivalent rate of 535 microSv d(-1). DOSTEL measurements were also obtained during the Solar Particle Event on 15 April 2001.

Dosimetry inside MIR station using a silicon detector telescope (DOSTEL)

The dosimetry telescope (DOSTEL) was flown on the MIR orbital station during October 1997-January 1998. The mission average contributions to the absorbed dose rates (in water) were 126 +/- 4 microGy/d and 121 +/- 13 microGy/d for the GCR and the SAA component, respectively. The mean quality factors (ICRP60) deduced from the LET-spectra are 3.5 +/- 0.2 (GCR) and 1.3 +/- 0.1 (SAA). Separate LET spectra and temporal variations of the absorbed dose rates and of the mean quality factors are presented for these two radiation components as well as for solar energetic particles of the November 6, 1997 event.

Behavioral and hormonal effects of exogenous vasotocin and corticosterone in the green treefrog

Vasotocin (AVT) promotes courtship in a wide range of vertebrates. However, this effect is not independent of steroid hormones. For example, androgens may work in concert with AVT and corticosterone (CORT) may work to oppose AVT action. In frogs, AVT promotes calling, and in some species, CORT inhibits calling. In addition, androgens are known to modulate AVT in the brain, and CORT may depress androgen secretion. Previous work in amphibians has suggested that AVT promotes courtship by overcoming a CORT-mediated stress response. Possible behavioral and hormonal interactions among AVT, CORT, and androgens were investigated in wild, free-living green treefrogs (Hyla cinerea). Saline, AVT, CORT, or a combination of AVT and CORT were administered to calling males, and several measures of spontaneous calling were evaluated for 1.5 h following injection. Plasma testosterone, dihydrotestosterone, and CORT were also measured. Saline-injected males had low CORT levels, and AVT and CORT injection elevated plasma CORT levels. AVT increased the likelihood of calling, but, in males who did call, AVT did not influence latency to call or how often they were observed calling. Very few saline-injected males resumed calling after injection, and therefore a CORT effect was only detectable in AVT-injected males. CORT inhibited calling in AVT-injected males only at the highest dose of CORT (40 microg); lower levels of CORT were unsuccessful at inhibiting AVT-induced calling. AVT appeared to have a specific effect on calling motivation. Further, the data suggest that disinhibition of a CORT response is not the primary mechanism by which AVT increases calling. In addition, CORT injection reduced endogenous androgen levels. Finally, endogenous androgens were negatively correlated with latency to begin calling, suggesting that they may have a positive effect on calling. These data indicate that AVT has positive effects on calling but provide only weak evidence that CORT inhibits courtship in this species.

Social signals influence hormones independently of calling behavior in the treefrog (Hyla cinerea)

Social signals play an important role in regulating hormone-behavior relationships. In anurans (frogs and toads), acoustic signals are an essential aspect of reproductive behavior; however, the physiological consequences of receiving social signals has remained largely undescribed. Each night for 5, 10, or 20 days, we presented acoustically isolated male treefrogs with a conspecific mating chorus, an array of tones, or no sound. We recorded calling rate of individuals throughout the experiment and collected blood before and after treatment. Days of stimulus exposure had no effect on any dependent measure. Acoustic treatment influenced steroid levels; testosterone, dihydrotestosterone, and corticosterone increased only in the group exposed to the chorus. Chorus-exposed males also showed an increase in stimulus-evoked calling. We found no correlation between androgens and calling within each treatment group. In addition, noncallers in the chorus group had higher levels of androgens than males in the tone or no sound groups. Further, chorus-exposed males with zero, low, or high rate of calling had similar levels of androgens. These data indicate that social signals increase circulating androgens independently of calling behavior. Elevated corticosterone associated with chorus reception did not inhibit calling behavior, and corticosterone showed no correlation with androgen levels.

Temporal call changes and prior experience affect graded signalling in the cricket frog

We investigated how male cricket frogs Acris crepitans, alter their advertisement calls in response to broadcasts of synthetic calls that were either 'attractive' or 'aggressive'. The stimulus calls differed in temporal but not spectral characteristics. Male cricket frogs produced a more aggressive call when presented with the aggressive stimulus, indicating that they perceived the temporal differences between the two call categories. The direction and degree of temporal and spectral changes depended on the relative dominant frequency of the resident and opponent. If the resident's dominant frequency was initially higher than the stimulus frequency, the pattern of change in dominant frequency mirrored that seen for the temporal call characters. In contrast, if the resident's initial dominant frequency was below that of the stimulus, then the temporal and spectral changes were in opposite directions. Furthermore, stimulus order influenced whether males responded differently to playbacks of aggressive and attractive calls; males that received the aggressive call first produced more aggressive calls during the aggressive stimulus, while males that received the attractive call first produced similar calls in response to the two stimuli. This suggests that experience with different types of signals influences the subsequent calling behaviour of male cricket frogs. Copyright 1999 The Association for the Study of Animal Behaviour.

[Intravesical instillation of trospium chloride, oxybutynin and verapamil for relaxation of the bladder detrusor muscle. A placebo controlled, randomized clinical test]

Therapy of detrusor hyperactivity with anticholinergic agents often is followed by adverse drug reactions. Intravesical application may be an interesting alternative. A randomised, single-blind, placebo-controlled, mono-centre clinical trial was carried out in 84 patients with urgency or urge incontinence. Due to intravesical administration of oxybutynin (CAS 5633-20-5) (n = 21) and trospium chloride (CAS 10405-02-4) (n = 21), respectively, a significant increase in maximum bladder capacity and decrease of detrusor pressure accompanied by an increase of residual urine were found in comparison to placebo in urodynamical investigations. Improvement of uninhibited bladder contractions occurred leading to higher filling volume. Under verapamil (CAS 152-11-4) (n = 21) no marked changes in the efficacy variables were found compared with placebo. All patients completed the study and were assessed with regard to efficacy and safety. No adverse events or marked changes in the vital signs were reported. The immediate onset of effect and the lack of adverse drug reactions suggest that treatment with topical oxybutynin or trospium chloride is an effective alternative in patients with intolerable side effects when orally treated. In addition, intravesical administration may be indicated in patients with bladder spasms due to indwelling catheter or in order to increase bladder capacity before percutaneous cystostomy.