Water is a radiation protection agent for ionised pyrrole

Radiation-induced damage of biological matter is an ubiquitous problem in nature. The influence of the hydration environment is widely discussed, but its exact role remains elusive. Utilising well defined solvated-molecule aggregates, we experimentally observed a hydrogen-bonded water molecule acting as a radiation protection agent for ionised pyrrole, a prototypical aromatic biomolecule. Pure samples of pyrrole and pyrrole(H2O) were outer-valence ionised and the subsequent damage and relaxation processes were studied. Bare pyrrole ions fragmented through the breaking of C-C or N-C covalent bonds. However, for pyrrole(H2O)+, we observed a strong protection of the pyrrole ring through the dissociative release of neutral water or by transferring an electron or proton across the hydrogen bond. Overall, a single water molecule strongly reduces the fragmentation probability and thus the persistent radiation damage of singly-ionised pyrrole.

Changes in the implantation procedures of pacemakers during the COVID-19 pandemic in Germany

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): BIOTRONIC

Background

During the beginning of the first pandemic wave beginning in spring 2020 a lot of elective EP procedures were set on hold. After a few months, the hospitals were allowed to proceed with their planned operations. The current investigation analyzed the changes in the number of cardiac pacemakers (PM) implantations in whole Germany.

Methods

We performed a data retrieval of the number of monthly first-time pacemaker implantations, i.e. single-, dual-chamber, or CRT-P, for the 2019 pre- and 2020 pandemic from the "Institut für das Entgeltsystem im Krankenhaus" (InEK) using OPS codes. This database provides data of all in-hospital procedures in Germany.

Results

The course of the implantation rates (January to September) is highlighted in the two figures, where figure 1 demonstrates the single- and dual-chamber PM, and figure 2 the CRT-P implantations in 2019 (blue line) compared to 2020 (red line). It can be clearly seen, that for the single- and dual-chamber PM, a gap occurs between March and Mai in 2020. On the contrary, for the sicker patients, who are in the need for CRT-P, the lines do no cross, significantly. Moreover, the number of CRT-P first-time implantations increased during May to September 2020.

Discussion

The present study highlights the course of first-time pacemaker implantations throughout the beginning of the COVID-19 pandemic in whole Germany. In contrast to single- and dual-chamber PM implantation rates, the number of CRT-P implantations remained stable during the first three months of the pandemic and then exceeded the rates from 2019. The progressive nature of heart failure resulting in the need for CRT may be one reason for not postponing the first-time implantation in the months March to May 2020.

Picosecond pulse-shaping for strong three-dimensional field-free alignment of generic asymmetric-top molecules

Fixing molecules in space is a crucial step for the imaging of molecular structure and dynamics. Here, we demonstrate three-dimensional (3D) field-free alignment of the prototypical asymmetric top molecule indole using elliptically polarized, shaped, off-resonant laser pulses. A truncated laser pulse is produced using a combination of extreme linear chirping and controlled phase and amplitude shaping using a spatial-light-modulator (SLM) based pulse shaper of a broadband laser pulse. The angular confinement is detected through velocity-map imaging of H⁺ and C²⁺ fragments resulting from strong-field ionization and Coulomb explosion of the aligned molecules by intense femtosecond laser pulses. The achieved three-dimensional alignment is characterized by comparing the result of ion-velocity-map measurements for different alignment directions and for different times during and after the alignment laser pulse to accurate computational results. The achieved strong three-dimensional field-free alignment of [Formula: see text] demonstrates the feasibility of both, strong three-dimensional alignment of generic complex molecules and its quantitative characterization.

Time-resolved relaxation and fragmentation of polycyclic aromatic hydrocarbons investigated in the ultrafast XUV-IR regime

Polycyclic aromatic hydrocarbons (PAHs) play an important role in interstellar chemistry and are subject to high energy photons that can induce excitation, ionization, and fragmentation. Previous studies have demonstrated electronic relaxation of parent PAH monocations over 10-100 femtoseconds as a result of beyond-Born-Oppenheimer coupling between the electronic and nuclear dynamics. Here, we investigate three PAH molecules: fluorene, phenanthrene, and pyrene, using ultrafast XUV and IR laser pulses. Simultaneous measurements of the ion yields, ion momenta, and electron momenta as a function of laser pulse delay allow a detailed insight into the various molecular processes. We report relaxation times for the electronically excited PAH^*, PAH^+* and PAH^2+* states, and show the time-dependent conversion between fragmentation pathways. Additionally, using recoil-frame covariance analysis between ion images, we demonstrate that the dissociation of the PAH²⁺ ions favors reaction pathways involving two-body breakup and/or loss of neutral fragments totaling an even number of carbon atoms.

Shame, self-identification with having a mental illness, and willingness to seek help in northeast Germany

We examined a general population sample (n = 1330) from an epidemiological study (SHIP), investigating whether shame, social distance and reluctance to self-identify as having a mental illness interfere with willingness to seek help for mental health problems. Analyses were stratified for life-time diagnosis of any mental illness. Shame was the strongest negative predictor for willingness to seek help (beta = -0.183, p < .001). Structured Estimation Modelling showed shame being a full mediator of a negative association between social distance and willingness. Our results corroborate the important role of shame as an impediment to help-seeking for mental health problems in the general population.

Strong-field physics in the molecular frame

Laser-aligned carbonyl-sulfide molecules were strong-field ionized using mid-infrared light. Investigating the strong-field effects in the molecular frame allowed to add novel facets to the understanding of the intrinsic nature of strong-field physics.

Ultrafast dynamics of UV-excited trans- and cis-ferulic acid in aqueous solutions

The ultrafast UV-induced processes of the neutral, anionic and dianionic forms of trans- and cis-ferulic acid (FA) in aqueous solution were studied by static and femtosecond time-resolved emission and absorption spectroscopy combined with quantum chemical calculations. In all cases, initial excitation populates the first ¹ππ* state. For the dianionic cis-isomer cFA^2-, electronic deactivation takes place with a time constant of only 1.4 ps, whereas in all other cases, excited-state deactivation happens more than ten times slower, on a time scale of ≈20 ps. The data suggest sequential de-excitation pathways, where initial sub-picosecond solvent rearrangement and structural changes are followed by internal conversion to an intermediate excited electronic state from which deactivation to the ground state proceeds. Considering the time scales, barrierless excited-state pathways are suggested only in the case of cFA^2-, where the observed formation of the isomerisation photoproduct tFA^2- provides clear evidence for a cis ⇄ trans isomerisation coordinate. In the other cases, pathways with an excited-state energy barrier, presumably along the same coordinate, are likely, given the longer excited-state lifetimes.

Photodissociation of aligned CH3I and C6H3F2I molecules probed with time-resolved Coulomb explosion imaging by site-selective extreme ultraviolet ionization

We explore time-resolved Coulomb explosion induced by intense, extreme ultraviolet (XUV) femtosecond pulses from a free-electron laser as a method to image photo-induced molecular dynamics in two molecules, iodomethane and 2,6-difluoroiodobenzene. At an excitation wavelength of 267 nm, the dominant reaction pathway in both molecules is neutral dissociation via cleavage of the carbon-iodine bond. This allows investigating the influence of the molecular environment on the absorption of an intense, femtosecond XUV pulse and the subsequent Coulomb explosion process. We find that the XUV probe pulse induces local inner-shell ionization of atomic iodine in dissociating iodomethane, in contrast to non-selective ionization of all photofragments in difluoroiodobenzene. The results reveal evidence of electron transfer from methyl and phenyl moieties to a multiply charged iodine ion. In addition, indications for ultrafast charge rearrangement on the phenyl radical are found, suggesting that time-resolved Coulomb explosion imaging is sensitive to the localization of charge in extended molecules.

Photophysics of indole upon X-ray absorption

A photofragmentation study of gas-phase indole (C₈H₇N) upon single-photon ionization at a photon energy of 420 eV is presented.

Impulsive laser-induced alignment of OCS molecules at FERMI

OCS full rotational revival dynamics induced by impulsive NIR alignment monitored by Coulomb explosion correlated fragments after S 2p excitation.

High-repetition-rate and high-photon-flux 70 eV high-harmonic source for coincidence ion imaging of gas-phase molecules

Unraveling and controlling chemical dynamics requires techniques to image structural changes of molecules with femtosecond temporal and picometer spatial resolution. Ultrashort-pulse x-ray free-electron lasers have significantly advanced the field by enabling advanced pump-probe schemes. There is an increasing interest in using table-top photon sources enabled by high-harmonic generation of ultrashort-pulse lasers for such studies. We present a novel high-harmonic source driven by a 100 kHz fiber laser system, which delivers 10¹¹ photons/s in a single 1.3 eV bandwidth harmonic at 68.6 eV. The combination of record-high photon flux and high repetition rate paves the way for time-resolved studies of the dissociation dynamics of inner-shell ionized molecules in a coincidence detection scheme. First coincidence measurements on CH₃I are shown and it is outlined how the anticipated advancement of fiber laser technology and improved sample delivery will, in the next step, allow pump-probe studies of ultrafast molecular dynamics with table-top XUV-photon sources. These table-top sources can provide significantly higher repetition rates than the currently operating free-electron lasers and they offer very high temporal resolution due to the intrinsically small timing jitter between pump and probe pulses.

The Molecular Zeeman-Effect in 1,3-Difluorobenzene and 3-Methylfurane

The rotational Zeeman effect of 1,3-difluorobenzene and 3-methylfurane has been studied at magnetic fields close to 25 kG. From the splittings of the rotational transitions the diagonal elements of the molecular g-tensors and the anisotropics of the diagonal elements of the magnetic susceptibility tensors have been determined as:

gaa=-0.0486±'0.0002, gbb = -0.0315 + 0.0003, gcc = +0.0116±0.0003,

(2 Xaa-Xbb-Xcc)NL = (46.6 ± 0.4) · 10-6 erg/ (G2 mole),

(2 Xbb-Xcc-Zaa)NL = (55.7 ± 0.4) · 10-6 erg/(G2 mole)

for 1,3-difluorobenzene and as

gaa = -0.0716 + 0.0006, gbb = -0.0370±0.0003, gcc =0.0222±0.0003,

(2 Xaa-Xbb-Xcc)NL = (25.7 ± 0.6) · 10-6 erg/(G2 mole),

(2 Xbb-Xcc-Xaa)NL = (43.1 ±0.5) · 10-6 erg/(G2 mole)

for 3-methylfurane. From comparison with related compounds position dependent substitution effects on the susceptibility anisotropics become appearent. The scheme of local atom susceptibilities is extended to fluorine containing molecules.

Effect of formal training in scaling, scoring and classification of the International Standards for Neurological Classification of Spinal Cord Injury

STUDY DESIGN

Prospective, longitudinal cohort study.

OBJECTIVES

To quantify the effect of formal training in the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) on the classification accuracy and to identify the most difficult ISNCSCI rules.

SETTINGS

European Multicenter Study on Human Spinal Cord Injury (EMSCI).

METHODS

EMSCI participants rated five challenging cases of full sensory, motor and anorectal examinations before (pre-test) and after (post-test) an ISNCSCI instructional course. Classification variables included sensory and motor levels (ML), completeness, ASIA Impairment Scale (AIS) and the zones of partial preservation.

RESULTS

106 attendees were trained in 10 ISNCSCI workshops since 2006. The number of correct classifications increased significantly (P<0.00001) from 49.6% (2628 of 5300) in pre-testing to 91.5% (4849 of 5300) in post-testing. Every attendee improved, 12 (11.3%) achieved 100% correctness. Sensory levels (96.8%) and completeness (96.2%) are easiest to rate in post-testing, while ML (81.9%) and AIS (88.1%) are more difficult to determine. Most of the errors in ML determination arise from sensory levels in the high cervical region (C2-C4), where by convention the ML is presumed to be the same as the sensory level. The most difficult step in AIS classification is the determination of motor incompleteness.

CONCLUSION

ISNCSCI training significantly improves the classification skills regardless of the experience in spinal cord injury medicine. These findings need to be considered for the appropriate preparation and interpretation of clinical trials in spinal cord injury.

The HSG procedure for modelling integrated urban wastewater systems

Whilst the importance of integrated modelling of urban wastewater systems is ever increasing, there is still no concise procedure regarding how to carry out such modelling studies. After briefly discussing some earlier approaches, the guideline for integrated modelling developed by the Central European Simulation Research Group (HSG - Hochschulgruppe) is presented. This contribution suggests a six-step standardised procedure to integrated modelling. This commences with an analysis of the system and definition of objectives and criteria, covers selection of modelling approaches, analysis of data availability, calibration and validation and also includes the steps of scenario analysis and reporting. Recent research findings as well as experience gained from several application projects from Central Europe have been integrated in this guideline.

From a black-box to a glass-box system: the attempt towards a plant-wide automation concept for full-scale biogas plants

Biogas plants gain worldwide increasing importance due to several advantages. However, concerning the equipment most of the existing biogas plants are low-tech plants. E.g., from the point of view of instrumentation, control and automation (ICA) most plants are black-box systems. Consequently, practice shows that many biogas plants are operated sub-optimally and/or in critical (load) ranges. To solve these problems, some new biogas plants have been equipped with modern machines and ICA equipment. In this paper, the authors will show details and discuss operational results of a modern agricultural biogas plant and the resultant opportunities for the implementation of a plant-wide automation.

Operational results of an agricultural biogas plant equipped with modern instrumentation and automation

Agricultural biogas plants based on energy crops gain more and more importance because of numerous energetic, environmental and agricultural benefits. In contrast to older biogas plants, the newest generation of biogas plants is equipped with modern ICA equipment and reliable machines/engines. In this paper, the authors present technical details and operational results of a modern full-scale agricultural biogas plant using energy crops.

A comparison of continuous flow and sequencing batch reactor plants concerning integrated operation of sewer systems and wastewater treatment plants

Integrated operation strategies for combined sewer and WWTP are becoming more and more popular because of numerous benefits. One can find many examples in literature, but many of these studies deal with partly fictitious systems and/or were accomplished within the planning. Hence most of these studies do not have to deal with the restrictions given by already built constructions. The authors, who worked on several integrated projects, will discuss the requirements of SBR and CFR plants concerning an implementation of integrated operation.

Trends in instrumentation, control and automation and the consequences on urban water systems

In recent years more and more on-line sensors have been used on different structures of urban water systems (UWS, i.e. wastewater treatment plants (WWTP), waterworks (WW), sewer systems). This development is influenced and driven by numerous trends, which will be discussed in this paper. For a better understanding, the discussion is illustrated with a factual example. The new possibilities of on-line measurement and automation technologies will also change the way as UWS will be planned, built and operated.

Instrumentation, control and automation for full-scale manure-based biogas systems

In recent years manure-based biogas plants (MBBP) have won more and more importance, because of the numerous ecological advantages. The processes are similar to processes, which have been well known for many decades in anaerobic wastewater/sludge treatment. As a result of technical progress and permanently rising prices for non-renewable energy, MBBPs have become more and more economically reasonable. Because of the economies of scale law more and more larger MBBPs are being built (250-2000 kW(el)). With regard to investment costs, reactor volumes and complexity etc., these (centralized) plants are comparable with small wastewater treatment plants (WWTP). Consequently, as actually in the case of the small WWTPs a rising use of instrumentation, control and automation (ICA) for larger MBBPs can be observed.

A process-dependent real-time controller for sequencing batch reactor plants: results of full-scale operation

This paper presents results of a research project, in which a process-dependent real-time control (RTC) strategy for a sequencing batch reactor plant was realised in full-scale. The cycle controller is based on NH4 analysers, NO3 probes, TSS probes and sludge level probes. With this new RTC strategy it was possible to increase the treatment capacity by 50%. By implementation of the new controller the TN, TP and NH4-N treatment efficiency could be improved significantly, too. The treatment efficiency concerning COD is comparable.

Integrated real-time control for a sequencing batch reactor plant and a combined sewer system

Integrated real-time control (RTC) concepts, which are trying to operate drainage systems and WWTPs depending on the current capacities of both systems, are becoming more and more important. While almost all publications in this field have been concentrating on continuous flow systems, this paper will present a project which has been initiated to realise an integrated RTC strategy for a Sequencing Batch Reactor (SBR) plant in simulation as well as in full-scale. The results of the simulation are that SBR plants can handle high hydraulic loads. The cost-benefit analysis shows that an integrated operation is reasonable concerning environmental and economic aspects. In order to verify the simulation results, full-scale operation has been started in January 2004. The first results seem to confirm the results of the simulation study.

Crossbow homicides

A total of eight cases of homicide by crossbow are reported, including six intentional, assault-like killings and one hired killer. The bolts showed a high penetration capacity despite the rather low kinetic energy (<100 J): a field-tip traversed one upper arm and the thorax (36 cm) and two broadheads caused perforating injuries of the thorax (25-26 cm). This was due to the high sectional density and the split-like penetration mechanism. Wound morphology was especially important if the perpetrator had extracted the bolt, which occurred in half of the cases. The shape of the entrance wound depended on the type of arrowhead: broadheads produced star-shaped to triangular wounds, field-tips caused circular, oval or slit-like injuries. Foreign material from the arrowhead was found inside two injuries. In assaults, the crossbow was used to hunt the victim down from a short distance which does not require practice but still has the advantage of a distance weapon. However, immediate incapacitation occurred rarely so that additional violence was frequently applied. The noiseless character of the weapon explains why many victims were taken by surprise and why the corpses initially remained unnoticed. Crossbows can therefore be considered ideal weapons for man hunting and some were bought for the very purpose of the killing.

Induction of pathogen resistance in barley by abiotic stress

Enhanced resistance of barley (Hordeum vulgare L. cv. Ingrid) against barley powdery mildew (Blumeria graminis f. sp. hordei race A6) was induced by abiotic stress in a concentration-dependent manner. The papilla-mediated resistance was not only induced by osmotic stress, but also by proton stress. Resistance was directly correlated with increasing concentrations of various salts in the nutrient solution. Resistance induced by proton stress also depended on the stress intensity. Resistance induction occurred even at low stress intensities. Any specific ion toxicity affecting the fungal growth directly, and therefore leading to enhanced pathogen resistance, can be excluded because of the independence of resistance induction of the ion used and of the time course of sodium accumulation in the leaves. BCI-4, a marker for benzo[1,2,3]thiadiazolecarbothioic acid S-methyl ester (BTH)-induced resistance was not induced by these abiotic stresses. However, resistance was induced in the same concentration-dependent manner by the application of the stress hormone ABA to the root medium. During the relief of water stress, resistance did not decrease constantly. On the contrary, after a phase of decreasing resistance for 24 h the pathogen resistance increased again for 48 h before decreasing finally to control levels.

A guideline for simulation studies of wastewater treatment plants

A guideline for simulation studies of wastewater treatment plants is proposed. The aim of the HSG-guideline is to define a reference quality level that helps to make the results of simulation studies comprehensible and comparable and therefore increases the quality and reliability of mathematical modelling in wastewater treatment. The paper gives a summary of the HSG-guideline, written by a group of university members from Germany, Austria and Switzerland.

Efficiency of SBR technology in municipal wastewater treatment plants

Four wastewater treatment plants running with sequencing batch reactor (SBR) technology have been evaluated in view of their effluent quality, treatment efficiency and energy demand. The plants are designed for approximately 5,000, 8,000, 15,000 and 25,000 population equivalents (p.e.). Although two of the plants were overloaded during the investigation time the effluent concentrations of nitrogen, especially ammonia, and phosphorus were low. The results show, that SBR plants which are designed according to German standards have additional capacities for degradation of organic matter and removal of nitrogen and phosphorus. Furthermore SBR plants with combined sewer systems are able to treat combined sewage very well. Thus SBR technology proves to be a good alternative for municipal sewage plants and can help to save investment costs.

Influenza: recommendations for vaccination and treatment

Influenza kills millions of people each year and has the potential to kill even more if proper vaccination and treatment protocols are not followed. This review provides the Louisiana State Office of Public Health and the Centers for Disease Control recommendations for vaccination and treatment of influenza.

Presence of Legionellaceae in warm water supplies and typing of strains by polymerase chain reaction

Outbreaks of Legionnaire's disease present a public health challenge especially because fatal outcomes still remain frequent. The aim of this study was to describe the abundance and epidemiology of Legionellaceae in the human-made environment. Water was sampled from hot-water taps in private and public buildings across the area of Göttingen, Germany, including distant suburbs. Following isolation, we used polymerase chain reaction in order to generate strain specific banding profiles of legionella isolates. In total, 70 buildings were examined. Of these 18 (26%) had the bacterium in at least one water sample. Legionella pneumophila serogroups 1, 4, 5 and 6 could be identified in the water samples. Most of the buildings were colonized solely by one distinct strain, as proven by PCR. In three cases equal patterns were found in separate buildings. There were two buildings in this study where isolates with different serogroups were found at the same time.

Are physicians aware of which of their patients have indwelling urinary catheters?

PURPOSE

Although infections associated with indwelling urinary catheters are common, costly, and morbid, the use of these catheters is unnecessary in more than one-third of patients. We sought to assess whether attending physicians, medical residents, and medical students are aware if their hospitalized patients have an indwelling urinary catheter, and whether physician awareness is associated with appropriate use of these catheters.

METHODS

The physicians and medical students responsible for patients admitted to the medical services at four university-affiliated hospitals were given a list of the patients on their service. For each patient, the provider was asked: "As of yesterday afternoon, did this patient have an indwelling urethral catheter?" Respondents' answers were compared with the results of examining the patient.

RESULTS

Among 288 physicians and students on 56 medical teams, 256 (89%) completed the survey. Of 469 patients, 117 (25%) had an indwelling catheter. There were a total of 319 provider-patient observations among these 117 patients. Overall, providers were unaware of catheterization for 88 (28%) of the 319 provider-patient observations. Unawareness rates by level of training were 21% for students, 22% for interns, 27% for residents, and 38% for attending physicians (P = 0.06). Catheter use was inappropriate in 36 (31%) of the 117 patients with a catheter. Providers were unaware of catheter use for 44 (41%) of the 108 provider-patient observations of patients who were inappropriately catheterized. Catheterization was more likely to be appropriate if respondents were aware of the catheter (odds ratio = 3.7; 95% confidence interval, 2.1 to 6.7, P <0.001).

CONCLUSION

Physicians are commonly unaware that their patients have an indwelling urinary catheter. Inappropriate catheters are more often "forgotten" than appropriate ones. System-wide interventions aimed at discontinuing unnecessary catheterization seem warranted.

The abdominojugular reflux sign

PURPOSE

The abdominojugular reflux sign is useful in diagnosing right ventricular failure, but is often performed and interpreted incorrectly. Our objective was to review the history, epidemiology, and pathophysiology of the abdominojugular reflux sign.

METHODS

We conducted a MEDLINE search of the English language reports published between 1966 and 1999 and a manual search of bibliographies of relevant papers.

RESULTS

A positive abdominojugular reflux sign is defined by an increase in the jugular venous pressure of greater than 3 cm, sustained for greater than 15 seconds. In the absence of left heart failure, a positive abdominojugular reflux sign should prompt consideration of impaired right ventricular preload, a decrease in right ventricular compliance, a decrease in right ventricular systolic function or an elevation in right ventricular afterload. In patients presenting with dyspnea, the abdominojugular reflux is useful in predicting congestive heart failure (LR+ 6.0 (95% CI; 0.8-51); LR- 0.78; (95% CI: 0.62 to 0.98)) and suggests pulmonary capillary wedge pressures of greater than 15 mm Hg (LR+ 6. 7 (95% CI: 3.3 to 13.4); LR- 0.08 (95% CI: 0.01 to 0.52)).

CONCLUSION

The abdominojugular reflux is not specific to any one disorder, but rather is a reflection of a right ventricle that cannot accommodate augmented venous return. Constrictive pericarditis, right ventricular infarction, and restrictive cardiomyopathy are common causes of a positive finding. Left ventricular failure may also induce the sign, but only when the pulmonary capillary wedge pressure is greater than 15. The one diagnosis not seen with abdominojugular reflux is cardiac tamponade.

Carbon allocation in ectomycorrhizas: identification and expression analysis of an Amanita muscaria monosaccharide transporter

Ectomycorrhizas are formed between certain soil fungi and fine roots of predominantly woody plants. An important feature of this symbiosis is the supply of plant-derived carbohydrates to the fungus. As a first step toward a better understanding of the molecular basis of this process, we cloned a monosaccharide transporter from the ectomycorrhizal fungus Amanita muscaria. Degenerate oligonucleotide primers were designed to match conserved regions from known fungal sugar transporters. A cDNA fragment of the transporter was obtained from mycorrhizal mRNA by reverse transcription-polymerase chain reaction. This fragment was used to identify a clone (AmMst1) encoding the entire monosaccharide transporter in a Picea abies/A. muscaria mycorrhizal cDNA library. The cDNA codes for an open reading frame of 520 amino acids, showing best homology to a Neurospora crassa monosaccharide transporter. The function of AmMST1 as monosaccharide transporter was confirmed by heterologous expression of the cDNA in a Schizosaccharomyces pombe mutant lacking a monosaccharide uptake system. AmMst1 was constitutively expressed in fungal hyphae under all growth conditions. Nevertheless, in mycorrhizas as well as in hyphae grown at monosaccharide concentrations above 5 mM, the amount of AmMst1 transcript increased fourfold. We therefore suggest that AmMst1 is upregulated in ectomycorrhizas by a monosaccharide-controlled mechanism.

Effects of crystalloid solutions on circulating lactate concentrations: Part 1. Implications for the proper handling of blood specimens obtained from critically ill patients

OBJECTIVES

a) To test the hypothesis that circulating lactate concentrations are the same in simultaneously collected arterial and central venous blood specimens; b) to test the hypothesis that even small amounts of crystalloid solutions, which are inadequately "cleared" from these indwelling arterial and venous catheters, can lead to clinically important and misleading changes in the measured lactate values.

DESIGN

A prospective, multiexperiment study.

SETTING

A critical care research laboratory and a 20-bed intensive care unit (ICU).

PATIENTS

Three hundred fifty-five patients.

INTERVENTIONS

Blood samples were collected.

MEASUREMENTS AND MAIN RESULTS

Experiment 1: Simultaneously collected arterial and central venous blood specimens were obtained on 148 occasions from 48 medical ICU patients receiving no lactated Ringer's solution (RL). Arterial and central venous lactate values were nearly identical in these patients. The correlation between the arterial and central venous lactate concentrations was excellent (r2 = .85; p < .0001) and the agreement between the arterial and central venous lactate concentrations was also excellent (bias and precision = 0.04 mmol/L and +/- 0.38 mmol/L, respectively). Experiment 2: Arterial and mixed venous blood samples were obtained from 100 percutaneous transluminal coronary angioplasty (PTCA) and 75 cardiac surgical patients immediately before the performance of these cardiac procedures. We found the central venous lactate concentrations to be higher than arterial lactate values in the cardiac surgical group, and there was a very poor correlation (r2 = .07) between arterial and central venous lactate values in the cardiac surgical group. The correlation between central venous and arterial lactate concentrations in the PTCA patients was excellent (r2 = .84) and similar to the findings of experiment 1. Since the cardiac surgical patients received RL and the PTCA patients received no RL, we speculated that the intravenous infusion of RL in the cardiac surgical group accounted for these discordant findings. To test this speculation, we performed experiments 3 and 4. Experiment 3: In a large bench study, blood specimens were divided into multiple 1-mL aliquot portions, to which 0.01, 0.05, 0.10, 0.50, or 1.0 mL of various crystalloid solutions, containing or not containing RL, were added. In a volume-dependent and linear manner, solutions containing RL increased the circulating lactate concentration from 10% to > 400% of the baseline lactate value. In a volume-dependent and linear fashion, the non-RL crystalloid solutions decreased the lactate concentration by 0 to 66% of the baseline nondiluted lactate concentration. Experiment 4: In 30 different cardiac surgical patients, we simultaneously obtained central venous and arterial blood specimens. Patients this time received no RL, and catheter lines were adequately cleared (removal > 5 mL) of crystalloid solutions. We found a correlation (r2 = .82; p < .0001) that was virtually identical to the findings of experiment 1 and to the findings in the PTCA group of experiment 2.

CONCLUSIONS

a) Arterial and central venous lactate concentrations are similar in hemodynamically stable critically ill patients, b) Even small amounts of RL-containing solutions in catheters used for blood sampling may cause false increases in the circulating lactate concentration. c) Even small amounts of non-RL crystalloid solutions in catheters used for blood sampling may falsely decrease circulating lactate values. d) When blood specimens are drawn from indwelling catheters, all crystalloid solutions must be cleared from the line.

Use of different anticoagulants in test tubes for analysis of blood lactate concentrations: Part 2. Implications for the proper handling of blood specimens obtained from critically ill patients

OBJECTIVES

a) To test the hypothesis that the measurement of the circulating lactate concentration is influenced by the anticoagulant in the test tube that contains the blood sample; b) to test the hypothesis that the measurement of the circulating lactate concentration is influenced by the tissue used for analysis.

DESIGN

A prospective, controlled study.

SETTING

A critical care research laboratory, a 20-bed intensive care unit (ICU), and the general wards.

SUBJECTS

Twenty-three ICU and ward patients with hyperlactatemia and 19 healthy volunteers.

INTERVENTIONS

Blood samples were collected for determination of blood lactate concentration.

MEASUREMENTS AND MAIN RESULTS

Venous blood samples (12 mL) were obtained from each of the 19 normal subjects and each 12-mL specimen was evenly divided into six aliquot portions (six test tubes). Experiment 1: Of the six tubes, two tubes were set aside for experiment 2. The other four tubes were used to test four anticoagulants (one anticoagulant per tube). The anticoagulants tested were: sodium heparin; EDTA; lithium heparin; and sodium citrate. Lactate concentrations were analyzed using an ion-selective, amperometric electrode that we have previously validated. There were no statistically significant differences between the lactate concentrations derived from blood samples stored in sodium heparin, EDTA, or lithium heparin (p > .05; n = 19; Student-Newman-Keuls' multiple comparisons test). The lactate concentration of blood stored in sodium citrate, however, was lower than all other anticoagulants (p < .001; n = 19; Student-Newman-Keuls' multiple comparisons). Experiment 2: Of the remaining two test tube samples from each subject, one tube contained sodium heparin and the other tube did not contain an anticoagulant. Each of these two tubes was centrifuged at 50 degrees F (10 degrees C) for 15 mins to obtain plasma and serum samples. Lactate concentrations were measured in the serum and plasma and compared with those concentrations found in whole blood samples from the tube containing sodium heparin from experiment 1. The plasma and serum lactate concentrations were consistently higher than the whole blood lactate values from the same specimen (p < .05; n = 42; Student-Newman-Keuls' multiple comparisons test). Since experiment 1 involved the collection of blood from healthy volunteers with normal lactate concentrations, we chose to investigate whether this discordance between plasma or serum and whole blood was dependent on the lactate concentration. To answer this question, we studied 23 patients with known hyperlactatemia and found that in subjects with a lactate concentration of < 2.2 mmol/L, there was a difference of 0.11 mmol/L in the mean values between plasma and whole blood concentrations (p < .0004; n = 19; paired t-test). In subjects with a lactate concentration of > 2.2 mmol/L, there was a difference of 0.14 mmol/L (p < .0001; n = 23; paired t-test) in the mean values between plasma and whole blood. In all samples at all concentrations, there was no significant difference between serum vs. plasma samples (p > .05; Student-Newman-Keuls' test).

CONCLUSIONS

a) Sodium citrate, as an anticoagulant, caused lower lactate concentrations to be measured as compared with heparin or EDTA; b) the measurement of lactate concentrations in plasma or serum samples yields a higher value than the concentration found in the original whole blood specimen.

Blood conservation in acute care and critical care

Blood conservation has evolved into an important issue in hospital-based medicine. Increased awareness of and worry about transfusion-associated diseases have prompted a focus on this important area. New technologies, including continuous intraarterial monitoring devices, microchemical technologies, new drug development (recombinant human erythropoietin and aprotinin) and intraoperative salvage techniques have made the concept of clinically important blood conservation possible. In this article, the authors review clinically important areas regarding blood conservation, which are subsequently detailed in this issue of AACN Clinical Issues. Emphasis is placed on the need for blood conservation in acute and critical care practice and the technologies available to achieve this goal.

[Fertility after extrauterine pregnancy. A 16-year retrospective study]

A retrospective investigation of fertility following extrauterine pregnancy during a period of 16 years in a central hospital was carried out. Out of 283 women with extrauterine pregnancy, if proved possible to investigate the postoperative fertility in 181 women. It was found that 71.8% of the patients conceived and 49.2% were delivered of living infants while 16% developed renewed extrauterine pregnancies. No significant differences were found in the frequencies of renewed extrauterine pregnancy and the number of liveborn infants between women who had been submitted to radical operation and women in whom conservative operative methods were employed. On the basis of this investigation and review of the literature, the present authors consider, that conservative operation should be employed where this is technically possible.

[Fathers of first infants--preparatory courses about delivery, experience of delivery and paternity leave]

In the Central Hospital in Randers, 233 fathers of first infants replied to a questionnaire which illustrated their attitudes to the preparatory courses about delivery, experience of delivery and attitudes to paternity leave. 65% of the fathers participated in the course and 74% stated that they considered that this had been profitable. Where 77% of the men were concerned, these considered that participation in delivery had been a positive experience. 73% of the men had planned paternity leave around the time of delivery, which emphasizes the need for this arrangement.