Towards a radon-in-water primary standard at LNHB

Despite widespread radon-in-water measurements, no primary radon-in-water standards currently exist. This work aims to bridge this gap by developing a system to produce radon-in-water reference materials. The system relies on cryogenic, loss-free transfer of radon, which is standardized through defined solid angle measurements, to a radon standard in water. It allows for preparation of liquid scintillation and gamma-ray spectrometry samples with traceable radon-in-water concentrations. The system's design, functionality, and the results of pilot performance tests are described.

Establishment of Ph. Eur. Somatropin/desamidosomatropin resolution mixture Chemical Reference Substance batch 2

The control of somatropin products according to the monographs of the European Pharmacopoeia (Ph. Eur.) requires a system suitability preparation for the test for related proteins by liquid chromatography. A preparation consisting in a mixture of somatropin and desamidosomatropin, such as the Ph. Eur. Somatropin/desamidosomatropin resolution mixture Chemical Reference Substance (CRS), is to be used to ascertain adequate resolution of the chromatographic setup. Due to low stocks, the Biological Standardisation Programme (BSP) of the Council of Europe and the European Union ran a study to establish a new batch of this system suitability CRS. A freeze-dried candidate batch (cCRS2) was produced and tested at the European Directorate for the Quality of Medicines and HealthCare (EDQM, Council of Europe). The resolution between the peaks due to somatropin and desamidosomatropin was 1.7 and the symmetry factor for the somatropin peak was 1.2. The mean percentage area of the desamidosomatropin peak was 14.6 %. These results showed that cCRS2 is suitable for its intended purpose. Based on these data, in May 2020 the Ph. Eur. Commission established the candidate batch as Ph. Eur. Soma-tropin/desamidosomatropin resolution mixture CRS batch 2.

How Fast Can Nurses Learn Therapeutic Communication Skills? A Pilot Study on Brief Hypnotic Communication Training Conducted with Oncology Nurses

Objective: This project aimed to train nurses on an oncology unit in hypnotic communication to reduce treatment-related pain and anxiety in their patients. A pilot study was conducted to assess changes in hypnotic communication behaviors associated with the training.

Methods: Nurses were recruited and their interactions during a simulated patient admission for treatment (before and after training) were recorded. Hypnotic communication skills were assessed by independent reviewers using a training checklist listing different hypnotic communication techniques and a validated assessment scale (Sainte-Justine Hypnotic Communication Assessment Scale, SJ-HCAS).

Results: Seven nurses were evaluated. Wilcoxon paired-sample tests (pre–post) reported significant improvement with large effect sizes in the total score of the training grid (P = 0.034, r = 0.832) and significant improvement with large effect sizes in the relational (P = 0.018, r = 0.930) and total (P = 0.021, r = 0.903) scores of the SJ-HCAS.

Conclusion: This pilot study shows promising results regarding the effectiveness of hypnotic communication training for nurses. These acquired skills could translate into improved treatment experience with patients and could be transferred to other professionals and settings in the health care system.

P–756 Predictive factors influencing multiple live births in cumulative IVF cycles: retrospective analysis of over 265000 embryo transfer procedures from the national French registry

Study question

What are the factors that could predict the number of embryos to be transferred in order to diminish risk of multiple pregnancies?

Summary answer

Single embryo transfer (SET) is advisable for <38 year-old women in fresh cycles and for <35 year-old women in FET whatever the IVF number attempts.

What is known already

Multiple pregnancies are associated to increased maternal and perinatal complications. Risks associated to multiple implantations are significantly reduced with SET policy. However, while SET is more assertive with a lesser negative impact in younger patients (<35 years), its feasibility is less evident for the older population, whom oocyte quality is likely compromised. A double embryo transfer (DET) could improve chances of implantation and shorten their time to pregnancy. Identification of risk factors for multiple pregnancies could help in decision making for a double or SET and reduce chances for multiple gestations without reducing the chances to achieve pregnancy.

Study design, size, duration

A retrospective study from the national French data registry provided and approved by the Agence de la Biomédecine was performed. A total of 196530 fresh and 68913 frozen cycles from women aged 18–43 year-old were included (2014–2017). Risk factors assessed included women’s age, number of attempts, number of oocytes, fertilization rate, embryo stage, number of embryos transferred, number of supernumerary embryos frozen. Secondary infertility, oocyte donor, oocyte freezing, PGT, freeze-all and IVM cycles were excluded.

Participants/materials, setting, methods

Cumulative cycles derived from 65% of ICSI, 32% of IVF and 3,2% IVF/ICSI. The distribution of patients age at oocyte retrieval was 60% < 35, 21% < 38, 11% < 40, and 8% ≥ 40 years old. Multivariable logistic regression was conducted to calculate adjusted odds ratios with 95% confidence intervals for live birth chance and multiple live birth risk associated with each risk factor.

Main results and the role of chance

The chances of obtaining a cumulative live birth decreases with increased patients age (OR 0.71 for 35–38 years and 0.47 for 38–40 years, p < 0.00001), with increased number of attempts (from OR 0.87 for attempt = 2 to OR 0.74 for attempt ≥ 4, p < 0.00001), and for frozen embryos transferred (OR 0.14, p < 0.00001). The chances of live birth increases with the increased number of oocytes (from OR 1.33 for 4–12 to OR 1.52 for > 18, p < 0.00001 in all cases), with a fertilisation rate >40% (OR 1.29, p < 0.00001), with blastocyst transfer (OR 1.29, p < 0.00001), with the increase on the number of frozen embryos (OR 7.37 for >1, OR 13.08 for >2, and OR 16.92 for >6, p < 0.00001 in all cases) and number of embryos transferred (OR 1.42 for 2 embryos and OR 1.39 for >2 embryos, p < 0.00001 in all cases).

In case of live birth, the risks of multiple births when two embryos were transferred decreases in patients aged >38 years (OR 0.50, p < 0.00001) and for frozen embryos transferred (OR 0.65, p < 0.00001). The risk increases with a fertilisation rate >60% (OR 1.30, p < 0.00001), with blastocysts transfer (OR 1.34, p < 0.00001) and when at least one supernumerary embryo is frozen (OR > 1.30, p < 0.00001).

Limitations, reasons for caution

This study is limited in only providing a risk-benefit balance for multiples on the choice of transferring one or two embryos. Clinical data such as stimulation protocols and doses of gonadotropins were not considered in this evaluation.

Wider implications of the findings: This study provides help to develop a strategy for the medical staff in the decision making for the number of embryos to be transferred. It may also serve as a patient’s information aid and help to improve their chances of achieving a health singleton if pregnant.

Trial registration number

Not applicable

Simulation of the response of an ionization chamber to 214Bi emission. Application to the measurement of 222Rn

PENELOPE simulations of a Vinten ionization chamber (IC) were performed to investigate the influence of the thickness of glass-ampoules used in ²²²Rn standardization. The simulation reveals a non-negligible variation of the energy deposited in the chamber gas region (which may induce a proportional variation of the measured current) when considering the β transition emissions of the daughters of ²²²Rn. This reinforces the idea of using a specialist container (made of metal to preserve the integrity of the container) that would circulate between the metrology laboratories in the context of international comparison exercises using the BIPM international reference system (SIR).

[Precariousness and diabetes: prevention using networks]

Precariousness and diabetes: prevention using networks. This article describes the impact of deprivation on prevalence of diabetes and the importance to integrate the socioeconomic aspect of patients while treating a chronic disease such as diabetes which involves everyday gestures and behaviours. Intervention studies demonstrated that incidence of diabetes can be decrease and with alternatives approaches, patients with diabetes can develop coping skills.

Consistency of photon emission intensities for efficiency calibration of gamma-ray spectrometers in the energy range from 20keV to 80keV

The efficiency calibration for different high-purity germanium detectors in the low-energy range was established by the conventional method, using standard radioactive sources. The peak shapes were carefully analysed taking account of natural linewidth, full-energy width at half maximum and scattering. Complementary information was obtained by Monte Carlo simulation using the PENELOPE code, after optimization of the geometrical parameters. This was used to measure photon emission intensities of some low-energy emitting radionuclides, including ¹³³Ba, and compared to the tabulated values.

Direct measurement of alpha emission probabilities in the decay of 226Ra

High-resolution alpha-particle spectrometry was performed to determine the main alpha-particle emission probabilities in the decay of ²²⁶Ra. Thin, homogeneous sources were prepared by electrodeposition on stainless steel disks. Alpha spectra with an energy resolution of 20keV were obtained in three laboratories and analysed with different deconvolution algorithms. In two set-ups, a magnet system was used to deflect conversion electrons to avoid their coincidental detection with the alpha particles. Spectra taken at close range without a magnet system yielded biased results which cannot be fully compensated by statistical corrections for coincidence summing. The derived emission probabilities of the three main alpha decays are 94.07 (1)%, 5.93 (1)%, and 0.0059 (15)%, respectively. They are in excellent agreement with calculated values derived from the P(γ+ce) decay scheme balance, which solves the existing discrepancy problem with two previous direct measurements published in literature.

Photon emission intensities in the decay of U-235

New measurements of photon emission intensities in the decay of U-235 were performed. Source was prepared by deposition of a U-235 solution on glass plate. Standardization was carried out by defined solid angle alpha counting, giving the reference activity with 0.7% relative combined uncertainty. Gamma spectrometry was performed with accurately calibrated high-purity germanium detectors. Corrections for source geometry and coincidence summing effects were applied. The reference line (185.72keV) intensity was obtained with 1.3% relative standard uncertainty.

Cluster randomized trial to evaluate the impact of team training on surgical outcomes

Background

The application of safety principles from the aviation industry to the operating room has offered hope in reducing surgical complications. This study aimed to assess the impact on major surgical complications of adding an aviation-based team training programme after checklist implementation.

Methods

A prospective parallel-group cluster trial was undertaken between September 2011 and March 2013. Operating room teams from 31 hospitals were assigned randomly to participate in a team training programme focused on major concepts of crew resource management and checklist utilization. The primary outcome measure was the occurrence of any major adverse event, including death, during the hospital stay within the first 30 days after surgery. Using a difference-in-difference approach, the ratio of the odds ratios (ROR) was estimated to compare changes in surgical outcomes between intervention and control hospitals.

Results

Some 22 779 patients were enrolled, including 5934 before and 16 845 after team training implementation. The risk of major adverse events fell from 8·8 to 5·5 per cent in 16 intervention hospitals (adjusted odds ratio 0·57, 95 per cent c.i. 0·48 to 0·68; P < 0·001) and from 7·9 to 5·4 per cent in 15 control hospitals (odds ratio 0·64, 0·50 to 0·81; P < 0·001), resulting in the absence of difference between arms (ROR 0·90, 95 per cent c.i. 0·67 to 1·21; P = 0·474). Outcome trends revealed significant improvements among ten institutions, equally distributed across intervention and control hospitals.

Conclusion

Surgical outcomes improved substantially, with no difference between trial arms. Successful implementation of an aviation-based team training programme appears to require modification and adaptation of its principles in the context of the the surgical milieu. Registration number: NCT01384474 (http://www.clinicaltrials.gov).

Development of a primary thoron activity standard for the calibration of thoron measurement instruments

The LNHB and IRSN are working on a reference atmosphere for thoron ((220)Rn) instrument calibration. The LNHB, as the national metrology institute for activity measurement in France, has to create a new thoron reference standard in order to estimate with accuracy the thoron concentration of a reference atmosphere. The measurement system presented in this paper is based on a reference volume using an alpha detector, which is able to measure thoron and its decay products to define the thoron concentration of a thoron reference atmosphere. This paper presents the first results with this new system using a well-known radon ((222)Rn) atmosphere and a thoron ((220)Rn) atmosphere.

Validation of efficiency transfer for Marinelli geometries

In the framework of environmental measurements by gamma-ray spectrometry, some laboratories need to characterize samples in geometries for which a calibration is not directly available. A possibility is to use an efficiency transfer code, e.g., ETNA. However, validation for large volume sources, such as Marinelli geometries, is needed. With this aim in mind, ETNA is compared, initially to a Monte Carlo simulation (PENELOPE) and subsequently to experimental data obtained with a high-purity germanium detector (HPGe).

Characterization of a cosmic suppression spectrometer

In this work, PENELOPE2008 and MCNP5 software packages were used to investigate the effect of simulation parameters such as cut-off energy of photons and electrons on the detector response function and peak escape intensity to assess their influence on the efficiency determination. The results showed a general agreement between the two codes, however both the intensity of escape peaks and total efficiency computed with PENELOPE2008 are higher than those obtained with MCNP5. Moreover, the calculated efficiencies are typically 8% higher than what is experimentally found in the low energy range. Further investigation was required to obtain better agreement and lead to better estimate of the real germanium crystal dimensions and dead layer.

Overexpression of RoDELLA impacts the height, branching, and flowering behaviour of Pelargonium × domesticum transgenic plants

KEY MESSAGE : We reported the cloning of a rose DELLA gene. We obtained transgenic Pelargonium lines overexpressing this gene which presented several phenotypes in plant growth, root growth, flowering time and number of inflorescences. Control of development is an important issue for production of ornamental plant. The plant growth regulator, gibberellins (GAs), plays a pivotal role in regulating plant growth and development. DELLA proteins are nuclear negative regulator of GA signalling. Our objective was to study the role of GA in the plant architecture and in the blooming of ornamentals. We cloned a rose DELLA homologous gene, RoDELLA, and studied its function by genetic transformation of pelargonium. Several transgenic pelargonium (Pelargonium × domesticum 'Autum Haze') lines were produced that ectopically expressed RoDELLA under the control of the 35S promoter. These transgenic plants exhibited a range of phenotypes which could be related to the reduction in GA response. Most of transgenic plants showed reduced growth associated to an increase of the node and branch number. Moreover, overexpression of RoDELLA blocked or delayed flowering in transgenic pelargonium and exhibited defects in the root formation. We demonstrated that pelargonium could be used to validate ornamental gene as the rose DELLA gene. RoDELLA overexpression modified many aspects of plant developmental pathways, as the plant growth, the transition of vegetative to floral stage and the ability of rooting.

Effect of water temperature increase on HO-1 expression in European sea bass (Dicentrarchus labrax L.) tissues

One of the most pertinent environmental factors influencing the marine organism life is temperature. It has been demonstrated that an increase of temperature is able to induce the synthesis of heat shock proteins (HSP). In this study we investigated the expression of HO-1 mRNA, also referred to as HSP32, in different tissues of European sea bass (Dicentrarchus labrax, L.) at several time points after increased temperature exposure (from 12degC to 30degC). Our results showed that HO-1 was not expressed in gills, heart, muscle and brain while it was expressed at a basal level in intestine. In liver, spleen and kidneys, HO-1 expression was influenced by temperature increases. In the spleen, we found a significant decrease of the HO-1 expression at the end of 4 weeks. In kidneys a very fast collapse of HO-1 expression level was recorded reaching null value as soon as one hour after exposure to 30degC. In liver, HO-1 expression increased from one hour of exposure to 30degC confirming HO-1 involvement to heat shock response in this organ. This increasing trend reached a 4.5-fold higher value than the initial level after 4 weeks.

Intercomparison of methods for coincidence summing corrections in gamma-ray spectrometry--part II (volume sources)

The second part of an intercomparison of the coincidence summing correction methods is presented. This exercise concerned three volume sources, filled with liquid radioactive solution. The same experimental spectra, decay scheme and photon emission intensities were used by all the participants. The results were expressed as coincidence summing corrective factors for several energies of (152)Eu and (134)Cs, and different source-to-detector distances. They are presented and discussed.

Effects of water temperature increase and heavy metals contamination on WAP65 gene expression in sea bass (Dicentrarchus labrax) liver

It has been previously demonstrated that "Warm temperature Acclimation-related 65 kD Protein" (WAP65) is involved in temperature acclimation, response to intoxication and infection, as well as in development. The expression of wap65-1 was investigated in the liver of European sea bass (Dicentrarchus labrax) during exposure to the increased temperature (from 12 deg C to 30 deg C) and during intoxication with four heavy metals: lead, cadmium, copper and zinc. Post temperature increase wap65 expression was highest after one hour at 30 deg C. After 1 to 4 weeks at 30 deg C wap65 transcript levels did not differ from the 12 deg C control group, similar to observations regarding the heat shock protein, hsp70. Upregulation of wap65 was detected after treatment (intoxication) with cadmium (0.5 μg/l). In contrast, a slight, but significant down regulation of wap65 was seen after copper (5 μg/l) intoxication. These data indicate that functional analyses of WAP65 are needed to understand the differential regulation of this gene by metals. The role of WAP65 may be similar to that of HSP70, which has generalized functions in responding to certain stressors and maintaining normal cell physiology.

cDNA sequencing and expression analysis of Dicentrarchus labrax heme oxygenase-1

The liver cDNA encoding heme oxygenase--1 (HO-1) was sequenced from European sea bass (Dicentrarchus labrax) (accession number no. EF139130). The HO-1 cDNA was 1250 bp in nucleotide length and the open reading frame encoded 277 amino acid residues. The deduced amino acid sequence of the European sea bass had 75% and 50% identity with the amino acid sequences of tetraodontiformes (Tetraodon nigroviridis and Takifugu rubripes) and human HO-1 proteins, respectively. A short hydrophobic transmembrane domain at the C--terminal region was found, and four histidine residues were highly conserved, including human his25 that is essential for HO catalytic activity. RT-PCR of mRNA from eight different European sea bass tissues revealed that, in a homeostatis state, the heme oxygenase--1 was abundant in the spleen and liver but not in the brain.

A genetic algorithm for designing distributed computer network topologies

The topological design of distributed packet switched networks consists of finding a topology that minimizes the communication costs by taking into account a certain number of constraints such as the delay and the reliability. This paper proposes a genetic algorithm (GA) for generating low-cost feasible computer network topologies subject to these constraints. The implementation of this algorithm has been subjected to extensive tests in order to measure the quality of solutions. Computational results confirm the efficiency of the GA to provide good solutions for medium-sized computer networks, in comparison with well-tried conventional methods.

Retroperitoneal fibrosis: a case report of spontaneous resolution

AIM

The purpose of this case report is to document an occurrence of spontaneous resolution of idiopathic retroperitoneal fibrosis and to review the investigation and management of this unusual condition.

MATERIALS AND METHODS

A detailed case summary of a patient with retroperitoneal fibrosis is presented. Current citations in Index medicus from the English-speaking literature of relevance to the topic were reviewed.

CONCLUSIONS

In this patient who refused open surgical intervention, bilateral stent placement allowed stabilization of renal function. CT-guided biopsy did not reveal malignancy. Serial CT imaging demonstrated gradual disappearance of the retroperitoneal mass. From the literature review, spontaneous resolution of this condition appears to be a rare phenomenon. Although often utilized, CT-guided biopsy may fail to exclude the presence of malignancy. Open surgical biopsy of the retroperitoneal mass and ureterolysis remain the standard of care for operative candidates. Establishing renal drainage and considering a trial of steroids or surveillance may be an option in carefully selected individuals.

Protein associated with Myc (PAM) is a potent inhibitor of adenylyl cyclases

Using the yeast two-hybrid assay and the second of the two large cytosolic domains of type V adenylyl cyclase (ACV) as bait, we identified a small region (amino acids 1028-1231) in the protein associated with Myc (PAM) as an interaction site for ACV. This small region of PAM as well as purified full-length PAM inhibited the activity of ACV. Additionally, full-length PAM was a very potent inhibitor of ACI and AC activities in S49 cyc(-) cells and HeLa cells with IC(50) values in the pm and low nm range. Moreover, the regulator of chromatin condensation 1-like domain of PAM (amino acids 446-1062) was sufficient and as potent as full-length PAM at inhibiting the activity of ACV. Interestingly, full-length PAM did not inhibit ACII activity that was stimulated by either forskolin of Galpha(s). When endogenous levels of PAM in HeLa cells were decreased using antisense oligodeoxynucleotides, the basal cAMP content was elevated, and the dose-response curve for vasoactive intestinal peptide-elicited cAMP accumulation in HeLa cells was shifted to the left. Therefore, we conclude that PAM is a very potent, novel inhibitor of specific isoforms of AC. Furthermore, the regulator of chromatin condensation 1-like domain of PAM is sufficient to exert the effects of the full-length protein on AC and decreases in endogenous PAM levels in HeLa cells can modulate both basal and agonist stimulated cAMP accumulation.

The C terminus of sprouty is important for modulation of cellular migration and proliferation

The Drosophila Sprouty (SPRY) protein has been shown to inhibit the actions of epidermal growth factor and fibroblast growth factor. However, the role of mammalian SPRY proteins has not been clearly elucidated. We postulated that human Sprouty2 (hSPRY2) is an inhibitor of cellular migration and proliferation. Indeed, using stably transfected HeLa cells, which expressed hemagglutinin (HA)-tagged hSPRY2 or hSPRY2 tagged at the C terminus with red fluorescent protein, we demonstrated that hSPRY2 inhibits the migration of cells in response to serum, epidermal growth factor, fibroblast growth factor, and platelet-derived growth factor. Additionally, hSPRY2 also inhibited the growth of HeLa cells in response to serum. Previously, two C-terminal domains on hSPRY2, which are necessary for its colocalization with microtubules (residues 123-177) or translocation to membrane ruffles (residues 178-194), have been identified (Lim, J., Wong, E. S., Ong, S. H., Yusoff, P., Low, B. C., and Guy, G. R. (2000) J. Biol. Chem. 275, 32837-32845). Therefore, using TAT-tagged hSPRY2 and its mutants, we determined the role of these two C-terminal domains in the inhibition of cell migration and proliferation. Our data show that the deletion of either of these two regions in hSPRY2 abrogates its ability to modulate cell migration in response to different growth factors and proliferation in response to serum. Therefore, we conclude that hSPRY2 inhibits the actions of a number of growth factors, and its C terminus, which is homologous among various SPRY isoforms, is important in mediating its biological activity.

Molecular biological approaches to unravel adenylyl cyclase signaling and function

Signal transduction through the cell membrane requires the participation of one or more plasma membrane proteins. For many transmembrane signaling events adenylyl cyclases (ACs) are the final effector enzymes which integrate and interpret divergent signals from different pathways. The enzymatic activity of adenylyl cyclases is stimulated or inhibited in response to the activation of a large number of receptors in virtually all cells of the human body. To date, ten different mammalian isoforms of adenylyl cyclase (AC) have been cloned and characterized. Each isoform has its own distinct tissue distribution and regulatory properties, providing possibilities for different cells to respond diversely to similar stimuli. The product of the enzymatic reaction catalyzed by ACs, cyclic AMP (cAMP) has been shown to play a crucial role for a variety of fundamental physiological cell functions ranging from cell growth and differentiation, to transcriptional regulation and apoptosis. In the past, investigations into the regulatory mechanisms of ACs were limited by difficulties associated with their purification and the availability of the proteins in any significant amount. Moreover, nearly every cell expresses several AC isoforms. Therefore, it was difficult to perform biochemical characterization of the different AC isoforms and nearly impossible to assess the physiological roles of the individual isoforms in intact cells, tissue or organisms. Recently, however, different molecular biological approaches have permitted several breakthroughs in the study of ACs. Recombinant technologies have allowed biochemical analysis of adenylyl cyclases in-vitro and the development of transgenic animals as well as knock-out mice have yielded new insights in the physiological role of some AC isoforms. In this review, we will focus mainly on the most novel approaches and concepts, which have delineated the mechanisms regulating AC and unravelled novel functions for this enzyme.

High-altitude pulmonary edema is initially caused by an increase in capillary pressure

BACKGROUND

High-altitude pulmonary edema (HAPE) is characterized by severe pulmonary hypertension and bronchoalveolar lavage fluid changes indicative of inflammation. It is not known, however, whether the primary event is an increase in pressure or an increase in permeability of the pulmonary capillaries.

METHODS AND RESULTS

We studied pulmonary hemodynamics, including capillary pressure determined by the occlusion method, and capillary permeability evaluated by the pulmonary transvascular escape of 67Ga-labeled transferrin, in 16 subjects with a previous HAPE and in 14 control subjects, first at low altitude (490 m) and then within the first 48 hours of ascent to a high-altitude laboratory (4559 m). The HAPE-susceptible subjects, compared with the control subjects, had an enhanced pulmonary vasoreactivity to inspiratory hypoxia at low altitude and higher mean pulmonary artery pressures (37 +/- 2 versus 26 +/- 1 mmHg, P<0.001) and pulmonary capillary pressures (19 +/- 1 versus 13 +/- 1 mmHg, P < 0.001) at high altitude. Nine of the susceptible subjects developed HAPE. All of them had a pulmonary capillary pressure >19 mm Hg (range 20 to 26 mmHg), whereas all 7 susceptible subjects without HAPE had a pulmonary capillary pressure < 19 mm Hg (range 14 to 18 mm Hg). The pulmonary transcapillary escape of radiolabeled transferrin increased slightly from low to high altitude in the HAPE-susceptible subjects but remained within the limits of normal and did not differ significantly from the control subjects.

CONCLUSIONS

HAPE is initially caused by an increase in pulmonary capillary pressure.

RT-PCR detection of Na,K-ATPase subunit isoforms in human umbilical vein endothelial cells (HUVEC): evidence for the presence of alpha1 and beta3

The endothelial Na,K-ATPase is an active component in maintaining a variety of normal vascular functions. The enzyme is characterized by a complex molecular heterogeneity that results from differential expression and association of multiple isoforms of both its alpha- and beta-subunits. The aim of the present study was to determine which isoforms of the Na,K-ATPase are expressed in human endothelial cells. HUVEC (human umbilical vein endothelial cells) were used as a model of well known human endothelial cells. The high sensitive method RT-PCR was used with primers specific for the various isoforms of the alpha- and beta-subunits of the Na,K-ATPase. The results show that HUVEC express alpha1-, but not alpha2-, alpha3- or alpha4-isoforms of the catalytic subunit and that beta3- but not beta2- or beta1-isoforms is present in these cells. These findings are in contradiction with our previous detection of Na,K-ATPase isoforms in HUVEC using antibodies (14). Such results raise the technical problem of the specificity of the available antibodies directed against the different isoforms as well as the question of the physiological relevance of the diversity of the Na,K-ATPase isoforms.

RT-PCR detection of the Na,K-ATPase beta3-isoform in human heart

The Na,K-ATPase is a heterodimer composed of an alpha-catalytic and a beta-glycoprotein subunit. At present, three different alpha-polypeptides (alpha1, alpha2, alpha3) and two distinct beta-isoforms (beta1 and beta2) have been detected in human heart. The aim of the present study was to determine whether or not the beta3-isoform of the Na,K-ATPase can be detected in human heart. Using the highly sensitive method of RT-PCR, we here show that human heart expresses the beta3-isoform of the Na,K-ATPase. Given the differences in pharmacological properties of the nine different Na,K-ATPase isoenzymes (containing all combinations of the subunit isoforms), the study of beta3-isoform regulation in human heart may be of interest in understanding the altered response of human myocardium to digitalis therapy during heart failure.

Inhibition of hypoxic pulmonary vasoconstriction by carbon monoxide in dogs

OBJECTIVE

We tested the hypothesis that carbon monoxide might participate in the modulation of hypoxic pulmonary vasoconstriction (HPV) by prostacyclin (PGI2) and nitric oxide.

DESIGN

Prospective, interventional study.

SETTING

University laboratory.

SUBJECTS

Nineteen intact anesthetized mongrel dogs.

INTERVENTIONS

Right heart catheterization for the measurements of mean pulmonary artery pressure (Ppa), left atrial pressure estimated from occluded Ppa (Ppao), pulmonary capillary pressure (Pcp) calculated from the Ppa decay curve after balloon occlusion, and cardiac output (Q); inferior vena cava balloon for the control of Q by manipulation of venous return; ventilation in hyperoxia (fraction of inspired O2, 0.4) or in hypoxia (Fio2, 0.1); inhibition of cyclooxygenase by indomethacin (Indo); inhibition of nitric oxide synthase by NG-nitro-l-arginine (L-NA); inhibition of heme oxygenase by mesoporphyrin IX (SnMP); inhalation of nitric oxide (20 ppm); and inhalation of carbon monoxide (100 ppm).

MEASUREMENTS AND MAIN RESULTS

The first seven dogs were weak responders to hypoxia as assessed by a hypoxia-induced increase in the gradient between Ppa and Ppao, measured at one level of Q kept constant, by an average of only 2 mm Hg (p = NS). This HPV was markedly increased by the combined administration of Indo and L-NA. A further enhancement of HPV was observed after the addition of SnMP, leading to severe pulmonary hypertension with an average increase in Ppa to 39 mm Hg. Inhaled nitric oxide inhibited HPV only after the combined administration of Indo, L-NA, and SnMP. Inhaled carbon monoxide had no effect. The next 12 dogs were stronger responders to hypoxia, as assessed by a hypoxia-induced increase in the gradient between Ppa and Ppao, measured at several levels of Q, by an average of 3 mm Hg (p <.05). This HPV was of the same magnitude after administration of placebo (n = 6) or SnMP (n = 6). Addition of Indo enhanced HPV to the same extent in the placebo and in the SnMP groups. Addition of L-NA induced a further enhancement of HPV, which was, however, greater in the SnMP group. There was a slight increase in the capillary-venous segment relative to the arterial segment in hypoxic conditions, but the partitioning of pulmonary vascular resistance was otherwise unaffected by nitric oxide, carbon monoxide, or PGI2.

CONCLUSIONS

Endogenous carbon monoxide modulates canine HPV only in the absence of nitric oxide. The vasodilation mediated by nitric oxide, PGI2, or carbon monoxide is essentially distributed between proximal and distal sites proportionally to the degree of constriction produced during hypoxia.