Middle Pleistocene re-organization of Australian Monsoon

The sensitivity of the Australian Monsoon to changing climate boundary conditions remains controversial due to limited understanding of forcing processes and past variability. Here, we reconstruct austral summer monsoonal discharge and wind-driven winter productivity across the Middle Pleistocene Transition (MPT) in a sediment sequence drilled off NW Australia. We show that monsoonal precipitation and runoff primarily responded to precessional insolation forcing until ~0.95 Ma, but exhibited heightened sensitivity to ice volume and pCO₂ related feedbacks following intensification of glacial-interglacial cycles. Our records further suggest that summer monsoon variability at the precessional band was closely tied to the thermal evolution of the Indo-Pacific Warm Pool and strength of the Walker circulation over the past ~1.6 Myr. By contrast, productivity proxy records consistently tracked glacial-interglacial variability, reflecting changing rhythms in polar ice fluctuations and Hadley circulation strength. We conclude that the Australian Monsoon underwent a major re-organization across the MPT and that extratropical feedbacks were instrumental in driving short- and long-term variability.

Attendance in a national screening program for diabetic retinopathy: a population-based study of 205,970 patients

AIMS

A nationwide diabetic retinopathy (DR) screening program has been established in Denmark since 2013. We aimed to perform an evaluation of adherence to DR screenings and to examine whether non-adherence was correlated to DR progression.

METHODS

The population consisted of a register-based cohort, who participated in the screening program from 2013 to 2018. We analyzed age, gender, marital status, DR level (International Clinical DR severity scale, none, mild-, moderate-, severe non-proliferative DR (NPDR) and proliferative DR (PDR)), comorbidities and socioeconomic factors. The attendance pattern of patients was grouped as either timely (no delays > 33%), delayed (delays > 33%) or one-time attendance (unexplained).

RESULTS

We included 205,970 patients with 591,136 screenings. Rates of timely, delayed and one-time attendance were 53.0%, 35.5% and 11.5%, respectively. DR level at baseline was associated with delays (mild-, moderate-, severe NPDR and PDR) and one-time attendance (moderate-, severe NPDR and PDR) with relative risk ratios (RRR) of 1.68, 2.27, 3.14, 2.44 and 1.18, 2.07, 1.26, respectively (P < 0.05). Delays at previous screenings were associated with progression to severe NPDR or PDR (hazard ratio (HR) 2.27, 6.25 and 12.84 for 1, 2 and 3+ delays, respectively). Any given delay doubled the risk of progression (HR 2.28).

CONCLUSIONS

In a national cohort of 205,970 patients, almost half of the patients attended DR screening later than scheduled or dropped out after first screening episode. This was, in particular, true for patients with any levels of DR at baseline. DR progression in patients with delayed attendance, increased with the number of missed appointments.

Fossil leaf wax hydrogen isotopes reveal variability of Atlantic and Mediterranean climate forcing on the southeast Iberian Peninsula between 6000 to 3000 cal. BP

Many recently published papers have investigated the spatial and temporal manifestation of the 4.2 ka BP climate event at regional and global scales. However, questions with regard to the potential drivers of the associated climate change remain open. Here, we investigate the interaction between Atlantic and Mediterranean climate forcing on the south-eastern Iberian Peninsula during the mid- to late Holocene using compound-specific hydrogen isotopes from fossil leaf waxes preserved in marine sediments. Variability of hydrogen isotope values in the study area is primarily related to changes in the precipitation source and indicates three phases of increased Mediterranean sourced precipitation from 5450 to 5350 cal. BP, from 5150 to 4300 cal. BP including a short-term interruption around 4800 cal. BP, and from 3400 to 3000 cal. BP interrupted around 3200 cal. BP. These phases are in good agreement with times of prevailing positive modes of the North Atlantic Oscillation (NAO) and reduced storm activity in the Western Mediterranean suggesting that the NAO was the dominant modulator of relative variability in precipitation sources. However, as previously suggested other modes such as the Western Mediterranean Oscillation (WeMO) may have altered this overall relationship. In this regard, a decrease in Mediterranean moisture source coincident with a rapid reduction in warm season precipitation during the 4.2 ka BP event at the south-eastern Iberian Peninsula might have been related to negative WeMO conditions.

OP0263-HPR MAJOR STRESSORS IN THE YEAR PRIOR TO RA DIAGNOSIS: IMPACT ON PATIENT-REPORTED OUTCOMES ONE YEAR LATER

Background:

Stress is implicated in RA onset and poorer prognoses through changes in neuro-endocrine and autoimmune function. Although many people with RA link disease onset to recent stressful life events, results from retrospective studies are unclear.

Objectives:

To describe the incidence of major stressors(+STRESS) in year prior to diagnosis and compare characteristics and patient-reported outcomes (PROs) of newly diagnosed RA patients with and without+STRESSat 0 and 12 months.

Methods:

Data were from early RA patients (symptoms <1 yr) enrolled in the Canadian Early Arthritis Cohort (CATCH) from 2007-17 who met 1987/2010 ACR/EULAR criteria and had ≥12 months of follow-up. Patients reported major psychological (death, divorce/separation, family, financial, other) and physical (motor vehicle accident, surgery, major illness/infection, other) stressors in previous year. We used independent t-tests and chi square to compare characteristics by stressors at baseline, and multivariable regression to examine the impact of+STRESSon disease activity and PROs at 1 year, adjusting for age, sex, education, fibromyalgia, and SJC.

Results:

The 1933 adults were mostly female (72%), with a mean (SD) age of 55 (15) years. 52% reported 1+ stressors in previous year; family (48%), financial stress (36%), death (35%), surgery (28%), and major illness (26%) were the most common stressors. Patients with +STRESS were more likely to be women, younger, have more comorbidities including fibromyalgia, and higher mean DAS28. Patients with +STRESS also had significantly higher mean pain, fatigue, depression, sleep disturbance, patient global, and HAQ scores at baseline.

At 1 year, SJC and the proportion in DAS28 REM was similar between groups. However, PROs (pain, HAQ, Fatigue, Pt Global, Depression, Poor Sleep) remained higher in+STRESS, with evidence of an additive effect for number of stressors and having both physical and psychological stressors (Table). The greatest impacts were on mood, sleep disturbance, and fatigue.

Conclusion:

In this pan-Canadian early RA cohort, more than half reported 1+ stressful life events in the year prior to diagnosis. Individuals reporting major stressors had significantly worse pain, patient global, disability, depression, fatigue, and sleep disturbance at diagnosis; 1 year later, though disease activity was similar between groups, the effects of +STRESS on PROs persisted. Early RA patients with recent major stressors may benefit from emotional support and stress reduction to optimize how they feel and function.

Mean (SD) or N (%)No Stress(N=928; 48%)Physical(N=131; 7%)Psychological(N=658; 34%)Both(N=216; 11%)Age56 (15)56 (15)53 (14)52 (15)Women622 (67%)82 (63%)512 (78%)174 (81%)College Education464 (50%)76 (58%)345 (52%)126 (58%)Rheum Dis Comorbid Index1.1 (1.2)1.4 (1.4)1.1 (1.3)1.4 (1.3)OA or Spinal pain168 (18%)35 (27%)117 (18%)55 (25%)Fibromyalgia diagnosis15 (2%)2 (2%)13 (2%)11 (5%)Symptom duration (months)5.6 (3.0)5.7 (3.0)5.9 (3.0)5.9 (3.0)DAS28 – mean5.0 (1.4)5.1 (1.5)5.0 (1.5)5.2 (1.4)MTX ±csDMARDs679 (73%)100 (76%)489 (74%)166 (77%)Oral Steroids295 (32%)40 (31%)215 (33%)55 (25%)Pain (0-10)5.3 (2.8)5.5 (2.9)5.7 (2.8)6.2 (2.8)HAQ-DI1.0 (0.7)1.2 (0.7)1.1 (0.7)1.3 (0.7)Fatigue (0-10)4.7 (3.1)5.0 (3.0)5.7 (2.9)5.9 (2.9)Patient Global (0-10)5.6 (2.9)6.0 (2.9)6.0 (2.9)6.4 (3.0)Depression (SF12 MCS < 45.6)329 (35%)54 (41%)356 (54%)123 (57%)Poor sleep (0-10)4.5 (3.4)4.8 (3.3)5.3 (3.2)6.0 (3.1)

Disclosure of Interests:

Nicole Andersen: None declared, Orit Schieir: None declared, Marie-France Valois: None declared, Gilles Boire Grant/research support from: Merck Canada (Registry of biologices, Improvement of comorbidity surveillance)

Amgen Canada (CATCH, clinical nurse)

Abbvie (CATCH, clinical nurse)

Pfizer (CATCH, Registry of biologics, Clinical nurse)

Hoffman-LaRoche (CATCH)

UCB Canada (CATCH, Clinical nurse)

BMS (CATCH, Clinical nurse, Observational Study Protocol IM101664. SEROPOSITIVITY IN A LARGE CANADIAN OBSERVATIONAL COHORT)

Janssen (CATCH)

Celgene (Clinical nurse)

Eli Lilly (Registry of biologics, Clinical nurse), Consultant of: Eli Lilly, Janssen, Novartis, Pfizer, Speakers bureau: Merck, BMS, Pfizer, Janet Pope Grant/research support from: AbbVie, Bristol-Myers Squibb, Eli Lilly & Company, Merck, Roche, Seattle Genetics, UCB, Consultant of: AbbVie, Actelion, Amgen, Bayer, Boehringer Ingelheim, Bristol-Myers Squibb, Eicos Sciences, Eli Lilly & Company, Emerald, Gilead Sciences, Inc., Janssen, Merck, Novartis, Pfizer, Roche, Sandoz, Sanofi, UCB, Speakers bureau: UCB, Glen Hazlewood: None declared, Louis Bessette Grant/research support from: AbbVie, Amgen, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck, Novartis, Pfizer, Roche, Sanofi, UCB Pharma, Consultant of: AbbVie, Amgen, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck, Novartis, Pfizer, Roche, Sanofi, UCB Pharma, Speakers bureau: AbbVie, Amgen, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck, Novartis, Pfizer, Sanofi, Carol Hitchon Grant/research support from: UCB Canada; Pfizer Canada, Diane Tin: None declared, Carter Thorne Consultant of: Abbvie, Centocor, Janssen, Lilly, Medexus/Medac, Pfizer

Speakers bureau: Medexus/Medac, Edward Keystone Grant/research support from: AbbVie, Amgen, Bristol-Myers Squibb, F. Hoffmann-La Roche Inc, Gilead, Janssen Inc, Lilly Pharmaceuticals, Pfizer Pharmaceuticals, Sanofi-Aventis, Consultant of: AbbVie, Amgen, AstraZeneca Pharma, Biotest, Bristol-Myers Squibb Company, Celltrion,

Crescendo Bioscience, F. Hoffmann-La Roche Inc, Genentech Inc, Gilead, Janssen Inc, Lilly

Pharmaceuticals, Merck, Pfizer Pharmaceuticals, Sandoz, UCB., Speakers bureau: Amgen, AbbVie, Bristol-Myers Squibb Canada, F. Hoffmann-La Roche Inc., Janssen Inc., Merck, Pfizer Pharmaceuticals, Sanofi Genzyme, UCB, Vivian Bykerk: None declared, Susan J. Bartlett Consultant of: Pfizer, UCB, Lilly, Novartis, Merck, Janssen, Abbvie, Speakers bureau: Pfizer, UCB, Lilly, Novartis, Merck, Janssen, Abbvie

Alterations of the bile microbiome in primary sclerosing cholangitis

BACKGROUND

Patients with primary sclerosing cholangitis (PSC) display an altered colonic microbiome compared with healthy controls. However, little is known on the bile duct microbiome and its interplay with bile acid metabolism in PSC.

METHODS

Patients with PSC (n=43) and controls without sclerosing cholangitis (n=22) requiring endoscopic retrograde cholangiography were included prospectively. Leading indications in controls were sporadic choledocholithiasis and papillary adenoma. A total of 260 biospecimens were collected from the oral cavity, duodenal fluid and mucosa and ductal bile. Microbiomes of the upper alimentary tract and ductal bile were profiled by sequencing the 16S-rRNA-encoding gene (V1-V2). Bile fluid bile acid composition was measured by high-performance liquid chromatography mass spectrometry and validated in an external cohort (n=20).

RESULTS

The bile fluid harboured a diverse microbiome that was distinct from the oral cavity, the duodenal fluid and duodenal mucosa communities. The upper alimentary tract microbiome differed between PSC patients and controls. However, the strongest differences between PSC patients and controls were observed in the ductal bile fluid, including reduced biodiversity (Shannon entropy, p=0.0127) and increase of pathogen Enterococcus faecalis (FDR=4.18×10^-5) in PSC. Enterococcus abundance in ductal bile was strongly correlated with concentration of the noxious secondary bile acid taurolithocholic acid (r=0.60, p=0.0021).

CONCLUSION

PSC is characterised by an altered microbiome of the upper alimentary tract and bile ducts. Biliary dysbiosis is linked with increased concentrations of the proinflammatory and potentially cancerogenic agent taurolithocholic acid.

Late Miocene climate cooling and intensification of southeast Asian winter monsoon

The late Miocene offers the opportunity to assess the sensitivity of the Earth's climate to orbital forcing and to changing boundary conditions, such as ice volume and greenhouse gas concentrations, on a warmer-than-modern Earth. Here we investigate the relationships between low- and high-latitude climate variability in an extended succession from the subtropical northwestern Pacific Ocean. Our high-resolution benthic isotope record in combination with paired mixed layer isotope and Mg/Ca-derived temperature data reveal that a long-term cooling trend was synchronous with intensification of the Asian winter monsoon and strengthening of the biological pump from ~7 Ma until ~5.5 Ma. The climate shift occurred at the end of a global δ¹³C decrease, suggesting that changes in the carbon cycle involving the terrestrial and deep ocean carbon reservoirs were instrumental in driving late Miocene climate cooling. The inception of cooler climate conditions culminated with ephemeral Northern Hemisphere glaciations between 6.0 and 5.5 Ma.

Know your fish: A novel compound-specific isotope approach for tracing wild and farmed salmon

The rapid expansion of the aquaculture industry with carnivorous fish such as salmon has been accompanied by an equally rapid development in alternative feed ingredients. This has outpaced the ability of prevailing authentication method to trace the diet and origins of salmon products at the retail end. To close this gap, we developed a new profiling tool based on amino acid δ¹³C fingerprints. With this tool, we discriminated with high-accuracy among wild-caught, organically, and conventionally farmed salmon groups, as well as salmon fed alternative diets such as insects and macroalgae. Substitution of fishmeal with macroalgae was detected at 5% difference level. The δ¹³C fingerprints of essential amino acids appear particularly well suited for tracing protein sources, and the non-essentials for tracing lipid origins (terrestrial vs. aquatic). In an industry constantly developing new feed proteins and functional additives, our method is a promising tool for tracing salmon and other seafood products.

Pteropods are excellent recorders of surface temperature and carbonate ion concentration

Pteropods are among the first responders to ocean acidification and warming, but have not yet been widely explored as carriers of marine paleoenvironmental signals. In order to characterize the stable isotopic composition of aragonitic pteropod shells and their variation in response to climate change parameters, such as seawater temperature, pteropod shells (Heliconoides inflatus) were collected along a latitudinal transect in the Atlantic Ocean (31° N to 38° S). Comparison of shell oxygen isotopic composition to depth changes in the calculated aragonite equilibrium oxygen isotope values implies shallow calcification depths for H. inflatus (75 m). This species is therefore a good potential proxy carrier for past variations in surface ocean properties. Furthermore, we identified pteropod shells to be excellent recorders of climate change, as carbonate ion concentration and temperature in the upper water column have dominant influences on pteropod shell carbon and oxygen isotopic composition. These results, in combination with a broad distribution and high abundance, make the pteropod species studied here, H. inflatus, a promising new proxy carrier in paleoceanography.

The dominant detritus-feeding invertebrate in Arctic peat soils derives its essential amino acids from gut symbionts

Supplementation of nutrients by symbionts enables consumers to thrive on resources that might otherwise be insufficient to meet nutritional demands. Such nutritional subsidies by intracellular symbionts have been well studied; however, supplementation of de novo synthesized nutrients to hosts by extracellular gut symbionts is poorly documented, especially for generalists with relatively undifferentiated intestinal tracts. Although gut symbionts facilitate degradation of resources that would otherwise remain inaccessible to the host, such digestive actions alone cannot make up for dietary insufficiencies of macronutrients such as essential amino acids (EAA). Documenting whether gut symbionts also function as partners for symbiotic EAA supplementation is important because the question of how some detritivores are able to subsist on nutritionally insufficient diets has remained unresolved. To answer this poorly understood nutritional aspect of symbiont-host interactions, we studied the enchytraeid worm, a bulk soil feeder that thrives in Arctic peatlands. In a combined field and laboratory study, we employed stable isotope fingerprinting of amino acids to identify the biosynthetic origins of amino acids to bacteria, fungi and plants in enchytraeids. Enchytraeids collected from Arctic peatlands derived more than 80% of their EAA from bacteria. In a controlled feeding study with the enchytraeid Enchytraeus crypticus, EAA derived almost exclusively from gut bacteria when the worms fed on higher fibre diets, whereas most of the enchytraeids' EAA derived from dietary sources when fed on lower fibre diets. Our gene sequencing results of gut microbiota showed that the worms harbour several taxa in their gut lumen absent from their diets and substrates. Almost all gut taxa are candidates for EAA supplementation because almost all belong to clades capable of biosynthesizing EAA. Our study provides the first evidence of extensive symbiotic supplementation of EAA by microbial gut symbionts and demonstrates that symbiotic bacteria in the gut lumen appear to function as partners both for symbiotic EAA supplementation and for digestion of insoluble plant fibres.

Binding Interactions of Agents That Alter α-Synuclein Aggregation

Further examination of peptides with well-folded antiparallel β strands as inhibitors of amyloid formation from α-synuclein has resulted in more potent inhibitors. Several of these had multiple Tyr residues and represent a new lead for inhibitor design by small peptides that do not divert α-synuclein to non-amyloid aggregate formation. The most potent inhibitor obtained in this study is a backbone cyclized version of a previously studied β hairpin, designated as WW2, with a cross-strand Trp/Trp cluster. The cyclization was accomplished by adding a d-Pro-l-Pro turn locus across strand termini. At a 2:1 peptide to α-synuclein ratio, cyclo-WW2 displays complete inhibition of β-structure formation. Trp-bearing antiparallel β-sheets held together by a disulphide bond are also potent inhibitors. ¹⁵N HSQC spectra of α-synuclein provided new mechanistic details. The time course of ¹⁵N HSQC spectral changes observed during β-oligomer formation has revealed which segments of the structure become part of the rigid core of an oligomer at early stages of amyloidogenesis and that the C-terminus remains fully flexible throughout the process. All of the effective peptide inhibitors display binding-associated titration shifts in ¹⁵N HSQC spectra of α-synuclein in the C-terminal Q109-E137 segment. Cyclo-WW2, the most potent inhibitor, also displays titration shifts in the G41-T54 span of α-synuclein, an additional binding site. The earliest aggregation event appears to be centered about H50 which is also a binding site for our most potent inhibitor.

Tracing carbon sources through aquatic and terrestrial food webs using amino acid stable isotope fingerprinting

Tracing the origin of nutrients is a fundamental goal of food web research but methodological issues associated with current research techniques such as using stable isotope ratios of bulk tissue can lead to confounding results. We investigated whether naturally occurring δ(13)C patterns among amino acids (δ(13)CAA) could distinguish between multiple aquatic and terrestrial primary production sources. We found that δ(13)CAA patterns in contrast to bulk δ(13)C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. Furthermore, we showed for two aquatic producers that their δ(13)CAA patterns were largely unaffected by different environmental conditions despite substantial shifts in bulk δ(13)C values. The potential of assessing the major carbon sources at the base of the food web was demonstrated for freshwater, pelagic, and estuarine consumers; consumer δ(13)C patterns of essential amino acids largely matched those of the dominant primary producers in each system. Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs.

Which goal for fluid therapy during colorectal surgery is followed by the best outcome: near-maximal stroke volume or zero fluid balance?

BACKGROUND

We aimed to investigate whether fluid therapy with a goal of near-maximal stroke volume (SV) guided by oesophageal Doppler (ED) monitoring result in a better outcome than that with a goal of maintaining bodyweight (BW) and zero fluid balance in patients undergoing colorectal surgery.

METHODS

In a double-blinded clinical multicentre trial, 150 patients undergoing elective colorectal surgery were randomized to receive fluid therapy after either the goal of near-maximal SV guided by ED (Doppler, D group) or the goal of zero balance and normal BW (Zero balance, Z group). Stratification for laparoscopic and open surgery was performed. The postoperative fluid therapy was similar in the two groups. The primary endpoint was postoperative complications defined and divided into subgroups by protocol. Analysis was performed by intention-to-treat. The follow-up was 30 days. The trial had 85% power to show a difference between the groups.

RESULTS

The number of patients undergoing laparoscopic or open surgery and the patient characteristics were similar between the groups. No significant differences between the groups were found for overall, major, minor, cardiopulmonary, or tissue-healing complications (P-values: 0.79; 0.62; 0.97; 0.48; and 0.48, respectively). One patient died in each group. No significant difference was found for the length of hospital stay [median (range) Z: 5.00 (1-61) vs D: 5.00 (2-41); P=0.206].

CONCLUSIONS

Goal-directed fluid therapy to near-maximal SV guided by ED adds no extra value to the fluid therapy using zero balance and normal BW in patients undergoing elective colorectal surgery.

Sequential analysis of biomarkers in cerebrospinal fluid and serum during invasive meningococcal disease

The aim of the present study was to determine the profile of different inflammatory molecules in serum and cerebrospinal fluid (CSF) during invasive meningococcal disease (IMD). Their relationship with IMD severity was also assessed. A cohort of 12 patients with IMD was investigated. Paired serum and CSF samples were obtained at the time of diagnostic and follow-up lumbar puncture and were examined using Luminex analysis. IMD severity correlated with serum interleukin-6 (IL-6) and interleukin-1 receptor antagonist (IL-1 ra) on admission. Furthermore, the CSF levels of IL-1 beta, IL-1 ra, IL-6, IL-8, macrophage inflammatory protein-1 beta (MIP-1 beta), and monocyte chemoattractant protein-1 (MCP-1) were significantly higher than their respective serum levels. The strongest correlations were found between serum concentrations of IL-1 beta and IL-1 ra, IL-6, IL-8, and MIP-1 beta, whereas the strongest correlations in CSF were found between endotoxin and IL-8, IL-17, MIP-1 beta, and MCP-1. As was expected, the concentrations of inflammatory molecules in both serum and CSF significantly decreased after antibiotic treatment. With regard to kinetics, a severe course of IMD correlated positively with rapid declines of CSF IL-6 and cortisol levels. Sequential multiple analyses revealed patterns of inflammatory responses that were associated with the severity of IMD, as well as with the compartmentalization and kinetics of the immune reaction.

155,000 Years of West African Monsoon and Ocean Thermal Evolution

A detailed reconstruction of West African monsoon hydrology over the past 155,000 years suggests a close linkage to northern high-latitude climate oscillations. Ba/Ca ratio and oxygen isotope composition of planktonic foraminifera in a marine sediment core from the Gulf of Guinea, in the eastern equatorial Atlantic (EEA), reveal centennial-scale variations of riverine freshwater input that are synchronous with northern high-latitude stadials and interstadials of the penultimate interglacial and the last deglaciation. EEA Mg/Ca-based sea surface temperatures (SSTs) were decoupled from northern high-latitude millennial-scale fluctuation and primarily responded to changes in atmospheric greenhouse gases and low-latitude solar insolation. The onset of enhanced monsoon precipitation lags behind the changes in EEA SSTs by up to 7000 years during glacial-interglacial transitions. This study demonstrates that the stadial-interstadial and deglacial climate instability of the northern high latitudes exerts dominant control on the West African monsoon dynamics through an atmospheric linkage.

Neutrophil and platelet dynamics at organ level after cardiopulmonary bypass: an in vivo study in neonatal pigs

The aim was to investigate if organ dysfunction is a consequence of cell accumulation in the tissue and whether this accumulation is caused by the cardiopulmonary bypass (CPB) procedure. Twenty-six piglets were used in the sham group (sternotomy, n=12) or in the CPB group (sternotomy, CPB, n=14). Isotope-labeled autologous (99m)Tc-neutrophils (PMNs) and (111)In-platelets were infused and dynamically followed at organ level with a gamma camera before, during, and 4 h after termination of CPB. The CPB group showed a 49% increase in (99m) Tc-PMNs in the kidneys in the postoperative period compared to a decrease of 2% in the sham group. A less marked decrease was observed in the lungs and peripheral blood between the two groups. The increased radioactivity at organ level post-CPB could be due to changes in flow, extraction in the organ or accumulation of cells, especially in the kidneys and lungs, and might contribute to temporary organ dysfunction postoperatively.

Influence of the growth substrate on ester-linked phospho- and glycolipid fatty acids of PAH-degrading Mycobacterium sp. LB501T

The influences of poorly water-soluble anthracene on ester-linked phospholipid fatty acid (PLFA) and glycolipid fatty acid (GLFA) profiles of Mycobacterium sp. LB501T were studied. Bacteria were cultivated on either anthracene or glucose (one culture with successively amended small doses of this substrate and one with excess concentrations) to distinguish between influences of the chemical structure and the bioavailability of the growth substrate. Results revealed that GLFA and PLFA profiles of M. sp. LB501T depended on the availability and the structure of the carbon source. Fatty acid profiles obtained with anthracene differed from those obtained with excess glucose. They were interpreted as a specific adaptation to this poorly bioavailable polycyclic aromatic hydrocarbon (PAH). In contrast, profiles obtained with low glucose concentrations showed clear signs of starvation stress. Stable carbon isotopic ratios (delta13C) of GLFA and PLFA of M. sp. LB501T were analysed to characterize the 13C-fractionation during the biosynthesis of individual fatty acids and to evaluate their value as markers for substrate usage. Although the delta13C values of PLFA and GLFA showed differential isotope fractionation during anthracene- and glucose-degradation, they were sufficiently distinct to be used as signatures of bacterial substrate usage.

Fraunhofer diffraction of atomic matter waves: electron transfer studies with a laser cooled target

We have constructed an apparatus combining the experimental techniques of cold target recoil ion momentum spectroscopy and a laser cooled target. We measure angle differential cross sections in Li(+)+Na-->Li+Na(+) electron transfer collisions in the keV energy regime with a momentum resolution of 0.12 a.u. yielding an order of magnitude better angular resolution than previous measurements. We resolve Fraunhofer-type diffraction patterns in the differential cross sections. Good agreement with predictions of the semiclassical impact parameter method is obtained.

Hydrogen and carbon isotope fractionation during aerobic biodegradation of benzene

The main aim of the study was to evaluate hydrogen and carbon isotope fractionation during biodegradation of benzene as a possible tool to trace the process in contaminated environments. Aerobic biodegradation of benzene by two bacterial isolates, Acinetobacter sp. and Burkholderia sp., was accompanied by significant hydrogen and carbon isotope fractionation with hydrogen isotope enrichment factors of -12.8 +/- 0.7 per thousand and -11.2 +/- 1.8 per thousand, respectively, and average carbon isotope enrichment factors of -1.46 +/- 0.06 per thousand and -3.53 +/- 0.26 per thousand, respectively. Inorganic carbon produced by Acinetobacter sp. was depleted in 13C by 3.6-6.2 per thousand as compared to the initial delta13C of benzene, while the produced biomass was enriched in 13C by 3.8 per thousand. The secondary aim was to determine isotope ratios of benzenes from different manufacturers with regard to the use of isotopes for source differentiation. While two of the four analyzed benzenes had similar delta13C values, each of them had a distinct delta2H-delta13C pair and delta2H values spread over a range of 66.5 per thousand. Thus, combined analyses of hydrogen and carbon isotopes may be a more promising approach to trace sources and/or biodegradation of benzene than measuring carbon isotopes only.

Use of isotopic and molecular techniques to link toluene degradation in denitrifying aquifer microcosms to specific microbial populations

Microcosms were inoculated with sediments from both a petroleum-hydrocarbon (PHC)-contaminated aquifer and from a nearby pristine aquifer and incubated under anoxic denitrifying conditions with [methyl-13C]toluene. These microcosms served as a laboratory model system to evaluate the combination of isotope (13C-labeling of polar-lipid-derived fatty acids) and molecular techniques (16S rRNA-targeting gene probes) to identify the toluene-metabolizing population. After total depletion of toluene, the following bacterial phospholipid fatty acids (PLFA) were 13C-enriched: 16:1omega7c, 16:1omega7t, 16:0, cy17:0, and 18:1omega7c. Pure culture experiments demonstrated that these compounds were also found in PLFA profiles of PHC-degrading Azoarcus spp. (beta-Proteobacteria) and related species. The origin of the CO2 evolved in the microcosms was determined by measurements of stable carbon isotope ratios. Toluene represented 11% of the total pool of mineralized substrates in the contaminated sediment and 54% in the pristine sediment. The microbial community in the microcosm incubations was characterized by using DAPI staining and whole-cell hybridization with specific fluorescently labeled 16S rRNA-targeted oligonucleotide probes. Results revealed that 6% of the DAPI-stained cells in the contaminated sediment and 32% in the pristine sediment were PHC-degrading Azoarcus spp. In biotic control microcosms (incubated under denitrifying conditions, no toluene added), Azoarcus spp. cells remained at less than 1% of the DAPI-stained cells. The results show that isotope analysis in combination with whole-cell hybridization is a promising approach to identify and to quantify denitrifying toluene degraders within microbial communities.

Does interpleural bupivacaine blockade reduce arterial hypoxemia and pain in endoscopic retrograde cholangiopancreatography? A prospective randomized trial

BACKGROUND AND STUDY AIMS

Interpleural blockade with bupivacaine has been used in operations and for the treatment of pain with promising results. Endoscopy may be followed by serious complications associated with the use of intravenous drugs. Drug-induced hypoxemia has an important role in the pathophysiology.

PATIENTS AND METHODS

A randomized study to assess whether interpleural bupivacaine blockade compared with a standard procedure reduced the risk of hypoxemia and the need of medication in patients undergoing endoscopic retrograde cholangiopancreatography (ERCP). Other variables studied were its acceptability to patients and morbidity.

RESULTS

Ninety patients were included. Interpleural blockade (n = 43) was followed by minor complications. The blockade itself induced mild hypoxemia in four patients (9%). Overall, eight patients (27%) developed hypoxemia. There were correlations between age, drugs given and hypoxemia in the total series and in the two study groups individually. During ERCP eight (19%) in the blockade group and 16 (34%) in the standard procedure group developed hypoxemia. During the recovery period the opposite pattern was observed: (26%) compared with four (9%) (p = 0.05). Drug requirements did not differ. Procedure-related discomfort did not differ. More patients in the blockade group would prefer another sedative procedure.

CONCLUSIONS

Interpleural bupivacaine blockade did not contribute to patients' comfort or safety during ERCP.

High-dose chemoradiotherapy and anti-B-cell monoclonal antibody-purged autologous bone marrow transplantation in mantle-cell lymphoma: no evidence for long-term remission

PURPOSE

The role for high-dose therapy and autologous stem-cell transplantation in mantle-cell lymphoma (MCL) is unknown. We retrospectively analyzed patients with chemosensitive disease who underwent high-dose chemoradiotherapy and anti-B-cell monoclonal antibody-purged autologous bone marrow transplantation (ABMT) for MCL in first remission, as well as following relapse from conventional therapy.

PATIENTS AND METHODS

Between August 1985 and April 1996, 28 patients underwent ABMT using a uniform ablative regimen with cyclophosphamide and total-body irradiation (TBI) and a bone marrow-purging regimen. Re-review of original tissue demonstrated that all patients had morphologic, phenotypic, and genotypic characteristics of MCL. MCL was the original diagnosis in 21 patients, whereas seven patients had a prior diagnosis of diffuse small cleaved-cell lymphoma.

RESULTS

Twenty patients received multiple regimens before ABMT, while eight underwent ABMT in first complete remission (CR)/partial remission (PR) following CHOP induction. At bone marrow harvest, only 18% of patients were in CR and overt BM infiltration was present in 57%. Following cyclophosphamide/TBI, no treatment-related deaths were seen. Nineteen of 28 patients have relapsed at a median time of 21 months (range, 3 to 70). Of eight patients transplanted in first CR/PR, five have relapsed. Nine patients are in continuous CR with a median follow-up time of 24 months (range, 10 to 135). Disease-free survival (DFS) and overall survival (OS) are estimated to be 31% and 62% at 4 years, respectively.

CONCLUSION

ABMT using cyclophosphamide/TBI conditioning may at best be effective in only a small fraction of patients with relapsed MCL. The lack of plateau with a median follow-up time of 24 months suggests cure may not be achievable. The role of this therapy in patients in first remission requires more study using better induction therapy to enhance the CR rate before ABMT.

Eradication of polymerase chain reaction detectable immunoglobulin gene rearrangement in non-Hodgkin's lymphoma is associated with decreased relapse after autologous bone marrow transplantation

In B-cell non-Hodgkin's lymphoma (NHL), as in other B-cell malignancies, clonal rearrangement of the third complementarity determining region (CDR III) of the immunoglobulin heavy chain gene (IgH) provides a useful marker for the detection of minimal residual disease (MRD) after treatment. To determine the clinical utility of IgH polymerase chain reaction (PCR), we analyzed peripheral blood (PB) and bone marrow (BM) samples from 25 patients with NHL with no PCR detectable chromosomal rearrangement who have undergone autologous bone marrow transplantation (ABMT). Patients with histologic bone marrow infiltration at the time of bone marrow harvest were selected for study since this provided us with diagnostic tissue samples. As an initial strategy DNA was amplified using consensus variable (VH) and joining (JH) region primers. In those cases failing to amplify using consensus region primers, PCR was performed using a panel of VH family-specific framework region 1 (FR1) primers. The clonal products were directly sequenced. From the V-N-D region nucleotide sequences, clone specific probes were constructed and used for subsequent detection of MRD. A clonal PCR product could be PCR amplified and directly sequenced in 18 (72%, 90% confidence intervals 54%-86%) of these 25 patients, 8 with diffuse and 10 with follicular NHL. Eight of these 18 patients have relapsed after ABMT. All had detectable lymphoma cells before relapse and the sequence of the CDR III region at the time of relapse was identical to that obtained at the time of ABMT. All 10 patients who remain in complete remission from 18 to 36 months after ABMT had eradication of PCR detectable lymphoma cells after ABMT, although in three patients PCR detectable MRD was detected early after ABMT. We conclude that sequencing and the use of patient specific IgH CDR III oligonucleotides probes provides a simple and highly reliable method to determine the specificity of the IgH PCR technique. The clinical utility of this technique is demonstrated by the finding that eradication of PCR detectable lymphoma cells in these patients is associated with decreased relapse after ABMT (P = .0002).

Active conformation of 1,4-dihydropyridine calcium entry blockers. Effect of size of 2-aryl substituent on rotameric equilibria and receptor binding

The conformational requisites at the receptor for unsymmetrically substituted phenyl-1,4-dihydropyridine calcium entry blockers are examined by screening a series of (2'-halophenyl)-1,4-dihydropyridines 1-4, with increasing bulk at the 2'-position of the phenyl ring, for their ability to relax potassium-contracted rabbit aortic smooth muscle and to competitively displace [3H]nitrendipine from its specific binding sites on guinea pig skeletal muscle. The fraction of synperiplanar rotamer in solution for these compounds, as determined by the nuclear Overhauser enhancement method, shows a positive correlation with vasorelaxant activity and receptor binding affinity. These findings are consistent with the synperiplanar rotamer of nonrigid unsymmetrically substituted phenyl 1,4-dihydropyridine calcium channel blockers being the receptor-bound conformation.