Non-contrast computed tomography features predict intraventricular hemorrhage growth

OBJECTIVES

Non-contrast computed tomography (NCCT) markers are robust predictors of parenchymal hematoma expansion in intracerebral hemorrhage (ICH). We investigated whether NCCT features can also identify ICH patients at risk of intraventricular hemorrhage (IVH) growth.

METHODS

Patients with acute spontaneous ICH admitted at four tertiary centers in Germany and Italy were retrospectively included from January 2017 to June 2020. NCCT markers were rated by two investigators for heterogeneous density, hypodensity, black hole sign, swirl sign, blend sign, fluid level, island sign, satellite sign, and irregular shape. ICH and IVH volumes were semi-manually segmented. IVH growth was defined as IVH expansion > 1 mL (eIVH) or any delayed IVH (dIVH) on follow-up imaging. Predictors of eIVH and dIVH were explored with multivariable logistic regression. Hypothesized moderators and mediators were independently assessed in PROCESS macro models.

RESULTS

A total of 731 patients were included, of whom 185 (25.31%) suffered from IVH growth, 130 (17.78%) had eIVH, and 55 (7.52%) had dIVH. Irregular shape was significantly associated with IVH growth (OR 1.68; 95%CI [1.16-2.44]; p = 0.006). In the subgroup analysis stratified by the IVH growth type, hypodensities were significantly associated with eIVH (OR 2.06; 95%CI [1.48-2.64]; p = 0.015), whereas irregular shape (OR 2.72; 95%CI [1.91-3.53]; p = 0.016) in dIVH. The association between NCCT markers and IVH growth was not mediated by parenchymal hematoma expansion.

CONCLUSIONS

NCCT features identified ICH patients at a high risk of IVH growth. Our findings suggest the possibility to stratify the risk of IVH growth with baseline NCCT and might inform ongoing and future studies.

CLINICAL RELEVANCE STATEMENT

Non-contrast CT features identified ICH patients at a high risk of intraventricular hemorrhage growth with subtype-specific differences. Our findings may assist in the risk stratification of intraventricular hemorrhage growth with baseline CT and might inform ongoing and future clinical studies.

KEY POINTS

• NCCT features identified ICH patients at a high risk of IVH growth with subtype-specific differences. • The effect of NCCT features was not moderated by time and location or indirectly mediated by hematoma expansion. • Our findings may assist in the risk stratification of IVH growth with baseline NCCT and might inform ongoing and future studies.

Patterns of acute ischemic stroke and intracranial hemorrhage in patients with COVID-19 : Results of a retrospective multicenter neuroimaging-based study from three central European countries

BACKGROUND

Coronavirus disease 2019 (COVID-19) is an infection which can affect the central nervous system. In this study, we sought to investigate associations between neuroimaging findings with clinical, demographic, blood and cerebrospinal fluid (CSF) parameters, pre-existing conditions and the severity of acute COVID-19.

MATERIALS AND METHODS

Retrospective multicenter data retrieval from 10 university medical centers in Germany, Switzerland and Austria between February 2020 and September 2021. We included patients with COVID-19, acute neurological symptoms and cranial imaging. We collected demographics, neurological symptoms, COVID-19 severity, results of cranial imaging, blood and CSF parameters during the hospital stay.

RESULTS

442 patients could be included. COVID-19 severity was mild in 124 (28.1%) patients (moderate n = 134/30.3%, severe n = 43/9.7%, critical n = 141/31.9%). 220 patients (49.8%) presented with respiratory symptoms, 167 (37.8%) presented with neurological symptoms first. Acute ischemic stroke (AIS) was detected in 70 (15.8%), intracranial hemorrhage (IH) in 48 (10.9%) patients. Typical risk factors were associated with AIS; extracorporeal membrane oxygenation therapy and invasive ventilation with IH. No association was found between the severity of COVID-19 or blood/CSF parameters and the occurrence of AIS or IH.

DISCUSSION

AIS was the most common finding on cranial imaging. IH was more prevalent than expected but a less common finding than AIS. Patients with IH had a distinct clinical profile compared to patients with AIS. There was no association between AIS or IH and the severity of COVID-19. A considerable proportion of patients presented with neurological symptoms first. Laboratory parameters have limited value as a screening tool.

Multilesion Segmentations in Patients with Intracerebral Hemorrhage: Reliability of ICH, IVH and PHE Masks

Background and Purpose: Fully automated methods for segmentation and volume quantification of intraparenchymal hemorrhage (ICH), intraventricular hemorrhage extension (IVH), and perihematomal edema (PHE) are gaining increasing interest. Yet, reliabilities demonstrate considerable variances amongst each other. Our aim was therefore to evaluate both the intra- and interrater reliability of ICH, IVH and PHE on ground-truth segmentation masks. Methods: Patients with primary spontaneous ICH were retrospectively included from a German tertiary stroke center (Charité Berlin; January 2016−June 2020). Baseline and follow-up non-contrast Computed Tomography (NCCT) scans were analyzed for ICH, IVH, and PHE volume quantification by two radiology residents. Raters were blinded to all demographic and outcome data. Inter- and intrarater agreements were determined by calculating the Intraclass Correlation Coefficient (ICC) for a randomly selected set of patients with ICH, IVH, and PHE. Results: 100 out of 670 patients were included in the analysis. Interrater agreements ranged from an ICC of 0.998 for ICH (95% CI [0.993; 0.997]), to an ICC of 0.979 for IVH (95% CI [0.984; 0.993]), and an ICC of 0.886 for PHE (95% CI [0.760; 0.938]), all p-values < 0.001. Intrarater agreements ranged from an ICC of 0.997 for ICH (95% CI [0.996; 0.998]), to an ICC of 0.995 for IVH (95% CI [0.992; 0.996]), and an ICC of 0.980 for PHE (95% CI [0.971; 0.987]), all p-values < 0.001. Conclusion Manual segmentations of ICH, IVH, and PHE demonstrate good-to-excellent inter- and intrarater reliabilities, with the highest agreement for ICH and IVH and lowest for PHE. Therefore, the degree of variances reported in fully automated quantification methods might be related amongst others to variances in ground-truth masks.

POS1545-HPR PATIENT SELF-SAMPLING IN RHEUMATOID ARTHRITIS: RESULTS FROM A RANDOMIZED CONTROLLED TRIAL

Background

Rheumatoid arthritis (RA) requires early diagnosis and tight surveillance of disease activity. Patient self-sampling of blood for the analysis of autoantibodies and inflammation markers could facilitate the identification of patients at-risk for RA and improve tight disease monitoring [1].

Objectives

A randomized, controlled trial to evaluate the feasibility, acceptability and accuracy of an upper arm self-sampling device (UA) and finger prick-test (FP) to measure capillary blood from RA patients for C-reactive protein (CRP) levels and the presence of IgM rheumatoid factor (RF IgM) and anti-cyclic citrullinated protein antibodies (anti-CCP IgG).

Methods

50 RA patients were randomly assigned in a 1:1 ratio to self-collection of capillary blood via UA or FP. Venous blood sampling (VBS) was performed as gold standard in both groups to assess the concordance of CRP levels as well as RF IgM and CCP IgG. General acceptability and pain during sampling were measured and compared between UA, FP and VBS. The number of attempts for successful sampling, requests for assistance, volume and duration of sample collection were also assessed.

Results

49/50 (98%) patients were able to successfully collect capillary blood. Overall agreement between capillary and venous analyses for CRP (0.992), CCP IgG (0.984) and RF IgM (0.994) were good. In both groups 4/25 (16%) needed a second attempt and 8/25 (32%) in the UA and 7/25 (28%) in the FP group requested assistance. Mean pain scores for capillary self-sampling (1.7/10 ± 1.1 (UA) and 1.9/10 ± 1.9 (FP)) were lower on a numeric rating scale compared to venous blood collection (UA: 2.8/10 ± 1.7; FP: 2.1 ± 2.0). UA patients were more likely to promote the use of capillary blood sampling (net promoter score: +28% vs. -20% for FP) and were more willing to perform blood collection at home (60%) vs. 32% for FP).

Conclusion

This study shows that self-sampling is accurate, feasible and well accepted among patients. The implementation could allow tight remote monitoring of disease activity as well as identifying patients at-risk for RA and potentially other rheumatic diseases.

References:

[1]Knitza J, Knevel R, Raza K, Bruce T, Eimer E, Gehring I, et al. Toward Earlier Diagnosis Using Combined eHealth Tools in Rheumatology: The Joint Pain Assessment Scoring Tool (JPAST) Project. JMIR Mhealth Uhealth. 2020;8:e17507.

Acknowledgements

We thank all patients for their participation in this study. This study is part of the PhD thesis of the first author JK (AGEIS, Université Grenoble Alpes, Grenoble, France). We thank Josefine Born and Deniz Krämer for their help recruiting patients.

Disclosure of Interests

Johannes Knitza Grant/research support from: Thermo Fisher Scientific, Novartis, Koray Tascilar: None declared, Nicolas Vuillerme: None declared, Ekaterina Vogt Employee of: Thermo Fisher Scientific, Paul Matusewicz Employee of: Thermo Fisher Scientific, Giulia Corte: None declared, Louis Schuster: None declared, Timothée Aubourg: None declared, Gerlinde Bendzuck: None declared, Marianne Korinth: None declared, Corinna Elling-Audersch: None declared, Arnd Kleyer: None declared, Sebastian Boeltz: None declared, Axel Hueber: None declared, Gerhard Krönke: None declared, Georg Schett: None declared, David Simon: None declared

Two-dimensional Fermi liquid with attractive interactions

We realize and study an attractively interacting two-dimensional Fermi liquid. Using momentum-resolved photoemission spectroscopy, we measure the self-energy, determine the contact parameter of the short-range interaction potential, and find their dependence on the interaction strength. We successfully compare the measurements to a theoretical analysis, properly taking into account the finite temperature, harmonic trap, and the averaging over several two-dimensional gases with different peak densities.

MCAK is present at centromeres, midspindle and chiasmata and involved in silencing of the spindle assembly checkpoint in mammalian oocytes

Mitotic centromere-associated kinesin (MCAK) is an ATP-dependent microtubule (MT) depolymerase regulated by Aurora kinase (AURK) phosphorylation and implicated in resolution of improper MT attachments in mitosis. Distribution of MCAK was studied in oocyte maturation by anti-MCAK antibody, anti-tubulin antibody, anti-AURKB antibody and anti-centromere antibody (ACA) and by the expression of MCAK-enhanced green fluorescent protein fusion protein in maturing mouse oocytes. Function was assessed by knockdown of MCAK and Mad2, by inhibiting AURK or the proteasome, by live imaging with polarization microscope and by chromosomal analysis. The results show that MCAK is transiently recruited to the nucleus and transits to spindle poles, ACA-positive domains and chiasmata at prometaphase I. At metaphase I and II, it is present at centrosomes and centromeres next to AURKB and checkpoint proteins Mad2 and BubR1. It is retained at centromeres at telophase I and also at the midbody. Knockdown of MCAK causes a delay in chromosome congression but does not prevent bipolar spindle assembly. MCAK knockdown also induces a meiosis I arrest, which is overcome by knockdown of Mad2 resulting in chiasma resolution, chromosome separation, formation of aberrant meiosis II spindles and increased hypoploidy. In conclusion, MCAK appears to possess a unique distribution and function in oocyte maturation. It is required for meiotic progression from meiosis I to meiosis II associated with silencing of the spindle assembly checkpoint. Alterations in abundance and activity of MCAK, as implicated in aged oocytes, may therefore contribute to the loss of control of cell cycle and chromosome behaviour, thus increasing risk for errors in chromosome segregation and aneuploidy.

Spindle formation, chromosome segregation and the spindle checkpoint in mammalian oocytes and susceptibility to meiotic error

The spindle assembly checkpoint (SAC) monitors attachment to microtubules and tension on chromosomes in mitosis and meiosis. It represents a surveillance mechanism that halts cells in M-phase in the presence of unattached chromosomes, associated with accumulation of checkpoint components, in particular, Mad2, at the kinetochores. A complex between the anaphase promoting factor/cylosome (APC/C), its accessory protein Cdc20 and proteins of the SAC renders APC/C inactive, usually until all chromosomes are properly assembled at the spindle equator (chromosome congression) and under tension from spindle fibres. Upon release from the SAC the APC/C can target proteins like cyclin B and securin for degradation by the proteasome. Securin degradation causes activation of separase proteolytic enzyme, and in mitosis cleavage of cohesin proteins at the centromeres and arms of sister chromatids. In meiosis I only the cohesin proteins at the sister chromatid arms are cleaved. This requires meiosis specific components and tight regulation by kinase and phosphatase activities. There is no S-phase between meiotic divisions. Second meiosis resembles mitosis. Mammalian oocytes arrest constitutively at metaphase II in presence of aligned chromosomes, which is due to the activity of the cytostatic factor (CSF). The SAC has been identified in spermatogenesis and oogenesis, but gender-differences may contribute to sex-specific differential responses to aneugens. The age-related reduction in expression of components of the SAC in mammalian oocytes may act synergistically with spindle and other cell organelles' dysfunction, and a partial loss of cohesion between sister chromatids to predispose oocytes to errors in chromosome segregation. This might affect dose-response to aneugens. In view of the tendency to have children at advanced maternal ages it appears relevant to pursue studies on consequences of ageing on the susceptibility of human oocytes to the induction of meiotic error by aneugens and establish models to assess risks to human health by environmental exposures.

Influence of follicular fluid meiosis-activating sterol on aneuploidy rate and precocious chromatid segregation in aged mouse oocytes

BACKGROUND

Follicular fluid meiosis-activating sterol (FF-MAS) protects young oocytes from precocious chromatid separation (predivision). Reduced expression of cohesion and checkpoint proteins and predivision has been hypothesized to occur in age-related aneuploidy in oocytes.

METHODS

To know whether FF-MAS also protects aged oocytes from predivision and from age-related non-disjunction, we analysed chromosome constitution in mouse oocytes matured spontaneously with or without 10 microM FF-MAS and in hypoxanthine (HX)-arrested young and aged oocytes induced to resume maturation by FF-MAS. Messenger RNA for checkpoint protein MAD2 and cohesion protein SMC1beta was compared between oocytes matured with or without FF-MAS.

RESULTS

Aged oocytes possessed many bivalents with single distal chiasma at meiosis I. Predivision was especially high in aged oocytes cultured sub-optimally to metaphase II in alpha-minimum essential medium (alpha-MEM). FF-MAS reduced predivision significantly (P < 0.001) but neither reduced non-disjunction nor induced aneuploidy in aged oocytes. Polyploidy was high in FF-MAS-stimulated maturation, in particular in the aged oocytes (P > 0.001). Relative levels of Smc1beta mRNA appeared increased by maturation in FF-MAS, and mitochondrial clustering was restored.

CONCLUSIONS

Sister chromatids of aged oocytes appear to be highly susceptible to precocious chromatid separation, especially when maturation is under sub-optimal conditions, e.g. in the absence of cumulus and FF-MAS. This may relate to some loss of chromatid cohesion during ageing. FF-MAS protects aged oocytes from predivision during maturation, possibly by supporting Smc1beta expression, thus reducing risks of meiotic errors, but it cannot prevent age-related non-disjunction. Aged oocytes appear prone to loss of co-ordination between nuclear maturation and cytokinesis suggesting age-related relaxed cell cycle control.

Spindles, mitochondria and redox potential in ageing oocytes

Studies of human oocytes obtained from women of advanced reproductive age revealed that spindles are frequently aberrant, with chromosomes sometimes failing to align properly at the equator during meiosis I and II. Chromosomal analyses of donated and spare human oocytes and cytogenetic and molecular studies on the origin of trisomies collectively suggest that errors in chromosome segregation during oogenesis increase with advancing maternal age and as the menopause approaches. Disturbances in the fidelity of chromosome segregation, especially at anaphase I, leading to aneuploidy are prime causes of reduced developmental competence of embryos in assisted reproduction, as well as being responsible for the genesis of genetic disease. This review provides an overview of spindle formation and chromosome behaviour in mammalian oocytes. Evidence of a link between abnormal mitochondrial function in oocytes and somatic follicular cells, and finally disturbances in chromosome cohesion and segregation, and cell cycle control in aged mammalian oocytes, are also discussed.

Metabolic changes associated with cluster root development in white lupin (Lupinus albus L.): relationship between organic acid excretion, sucrose metabolism and energy status

Under phosphorous deficiency, plants of white lupin (Lupinus albus L.) develop root clusters, which are also called proteoid roots due to their preferential presence in the Proteaceae. In their mature stage, these roots acidify the soil and excrete high amounts of carboxylates [up to 1.5 and 7 micromol (g FW)(-1) h(-1) of malate and citrate, respectively] enabling lupins to utilise sparingly available sources of phosphate. Using the amplified fragment length polymorphism (AFLP) technique, we identified genes predominantly expressed in juvenile and mature cluster roots. Transcripts for two enzymes involved in glycolysis, fructokinase and phosphoglucomutase, were identified in juvenile cluster roots and one, sucrose synthase, in mature cluster roots. In order to verify these observations we performed quantitative reverse transcription-polymerase chain reaction (RT-PCR) and could confirm the increased transcript level. Measurements of enzymatic activities showed that fructokinase and phosphoglucomutase activities increased in juvenile cluster roots, whereas sucrose synthase activity was maximal in mature cluster roots. These results indicate that formation of proteoid roots and citrate excretion increase sink strength locally. Production of citrate and inhibition of respiration are likely to result in an increased NADH/NAD+ ratio, which may be toxic for the plant. The fermentation pathway would allow oxidation of NADH by decarboxylation of pyruvate and subsequent reduction of the resulting acetaldehyde. Determination of alcohol dehydrogenase activity showed that this enzyme is strongly induced in mature proteoid roots. However, ethanol production was not increased, indicating that pyruvate is shunted to citrate synthesis and not to ethanol production.

An ABC-transporter of Arabidopsis thaliana has both glutathione-conjugate and chlorophyll catabolite transport activity

An ABC-transporter of Arabidopsis thaliana exhibiting high sequence similarity to the human (MRP1) and yeast (YCF1) glutathione-conjugate transporters has been analysed and used to complement a cadmium-sensitive yeast mutant (DTY168) that also lacks glutathione-conjugate transport activity. Comparison of the hydrophobicity plots of this A. thaliana MRP-like protein with MRP1 and YCF1 demonstrates that the transmembrane domains are conserved, even at the N-terminus where sequence identity is low. Cadmium resistance is partially restored in the complemented ycf1 mutant, and glutathione-conjugate transport activity can be observed as well. The kinetic properties of the A. thaliana MRP-like protein (AtMRP3) are very similar to those previously described for the vacuolar glutathione-conjugate transporter of barley and mung bean. Furthermore, a hitherto undescribed ATP-dependent transport activity could be correlated with the gene product, i.e. vesicles isolated from the complemented yeast, but not from DTY168 or the wild type, take up the chlorophyll catabolite Bn-NCC-1. The results indicate that the product of the MRP-like gene of A. thaliana is capable of mediating the transport of the two different classes of compounds.

The role of placental trophoblast in the pathophysiology of the antiphospholipid antibody syndrome

PROBLEM

The antiphospholipid (aPL) antibody syndrome is characterized by severe pregnancy complications, the cause of which remains unknown. We hypothesized that the placental trophoblast is a target for aPLs.

METHOD OF STUDY

The effects of monoclonal aPLs on trophoblast function, including the invasion of JAR into matrigel-coated filters and the effects of annexin V expression on BeWo, were investigated using choriocarcinoma models.

RESULTS

aPLs against phosphatidylserine (PS) significantly (P < 0.001) decreased the migration of JAR across the membrane. In the annexin V studies, undifferentiated BeWo did not express surface annexin V. After differentiation, BeWo expressed surface annexin V, which was removed in the presence of aPLs, resulting in increased binding of prothrombin.

CONCLUSIONS

PS is expressed on the trophoblast surface during differentiation and invasion of extracellular matrix. Our data suggest that aPLs against PS can directly affect trophoblast function by limiting the depth of decidual invasion and by concurrently creating a procoagulant surface on trophoblast exposed to the maternal circulation.

Antiphosphatidylserine antibody removes annexin-V and facilitates the binding of prothrombin at the surface of a choriocarcinoma model of trophoblast differentiation

OBJECTIVE

Trophoblast differentiation is associated with externalization of phosphatidylserine from the inner to the outer surface of the plasma membrane. In this study we tested the hypothesis that concurrent externalization and binding of annexin-V blocks the phosphatidylserine-rich surface from acting as a site for activation of coagulation and that antiphospholipid antibodies lead to a procoagulant state by preventing annexin-V binding.

STUDY DESIGN

A choriocarcinoma model of trophoblast differentiation, forskolin-activated BeWo cells and immunoperoxidase techniques were used to determine surface and cytoplasmic localization of annexin-V related to differentiation. Monoclonal immunoglobulin M antibodies against phosphatidylserine- and cardiolipin-dependent antigens were used to determine the effects of antiphospholipid antibodies on annexin-V localization and on the binding of prothrombin to the BeWo surface.

RESULTS

During differentiation BeWo cells externalized phosphatidylserine and increased the expression of surface annexin-V. Monoclonal antibody against phosphatidylserine removed annexin-V from the BeWo surface and increased binding of prothrombin.

CONCLUSION

Antiphosphatidylserine antibody induces sites for prothrombin binding on the surface of a BeWo model of trophoblast, most likely by removing annexin-V. This mechanism could explain the frequent observation of increased thrombosis at the maternal-fetal interface in miscarriages associated with antiphospholipid antibodies.

Monoclonal antiphosphatidylserine antibodies react directly with feline and murine central nervous system

OBJECTIVE

Antiphospholipid antibodies (aPL), especially against phosphatidylserine and cardiolipin, are associated with a variety of neurological disorders. While it is believed aPL react with endothelial cells to cause cerebral thrombosis, it is not known to what degree aPL react with neural tissue nor which particular aPL specificities may be more relevant. We investigated direct aPL reactivity with the central nervous system (CNS) using 3 monoclonal IgM aPL that differentiate between cardiolipin and phosphatidylserine dependent antigens.

METHODS

Brain and spinal cord from normal cat Felis domesticus and brain from CD-1 mice were reacted with aPL using indirect immunoperoxidase techniques. Monoclonal aPL were reacted with whole brain myelin by dot immunoblots.

RESULTS

Monoclonal D11A4, reactive with cardiolipin and not phosphatidylserine (CL+/PS-), did not react with any portion of the tissue. Both monoclonal 3SB9b (CL-/PS+) and BA3B5C4 (CL+/PS+) reacted in feline and murine CNS. Both labeled myelinated fibers in grey and white matter of brain and spinal cord in an identical pattern with positive control antibody against myelin basic protein and reacted with whole human brain myelin by dot immunoblot. 3SB9b (CL-+PS+) additionally reacted with ependyma and epithelium of the choroid plexus.

CONCLUSION

aPL, especially those reactive with phosphatidylserine dependent antigens, react directly with epitopes associated with myelin, brain ependyma, or choroid epithelium. Direct reactivity of aPL with nervous tissue may be relevant to neurological disorders.

Differential expression of genes coding for ABC transporters after treatment of Arabidopsis thaliana with xenobiotics

ATP-binding cassette (ABC) transporters are thought to be involved in many cellular detoxification mechanisms. Performing a BLAST search, we found four distinct expressed sequence tags (EST) of Arabidopsis thaliana highly similar to the human and fungal glutathione-conjugate ABC transporters. We studied the expression of the corresponding genes in response to various xenobiotics in an effort to gain information on their function. The abundance of transcripts corresponding to one of the genes (EST1) was not affected by the various compounds tested, whereas the abundance of transcripts corresponding to the other three genes (EST2, EST3, EST4) was increased by 1-chloro-2,4-dinitrobenzene, primisulfuron and IRL 1803. Treatment of Arabidopsis with either primisufuron or IRL 1803 resulted in a more than 40-fold increase in EST2-specific transcripts.

Implementing the packaging and packaging waste directive

Some Member States have already established systems to meet the recovery and recycling targets for packaging waste. This article reviews their differences and similarities.

How plants dispose of chlorophyll catabolites. Directly energized uptake of tetrapyrrolic breakdown products into isolated vacuoles

During the yellowing of leaves the porphyrin moiety of chlorophyll is cleaved into colorless linear tetrapyrrolic catabolites, which eventually are deposited in the central vacuoles of mesophyll cells. In senescent cotyledons of rape, Brassica napus, three nonfluorescent chlorophyll catabolites (NCCs), accounting for practically all the chlorophyll broken down, were found to be located in the vacuoles (vacuoplasts) prepared from protoplasts. Transport of catabolites across the tonoplast was studied with vacuoles isolated from barley mesophyll protoplasts in conjunction with a radiolabeled NCC, Bn-NCC-1, prepared from senescent rape cotyledons. The uptake of Bn-NCC-1 into vacuoles was against a concentration gradient and strictly dependent on MgATP and it followed saturation kinetics with a Km of approximately 100 microM. Although the hydrolysis of ATP was required, transport was apparently independent of the vacuolar proton pumps: accumulation of the NCC occurred both in the presence of the H+-ATPase inhibitor bafilomycin and after destroying the DeltapH between the vacuolar sap and the medium. ATP could be replaced by GTP or UTP, and the transport was inhibited in the presence of vanadate. Chlorophyll catabolites isolated from senescent barley leaves competed with the rape-specific substrate for uptake into the vacuoles. Compounds such as the glutathione conjugate of N-ethylmaleimide and taurocholate, which are known to be transported across the tonoplast in a primary active mode, did not significantly inhibit uptake of Bn-NCC-1. Although the heme catabolites biliverdin and bilirubin inhibited the uptake of the NCC, this effect is caused by unspecific binding to the vacuolar membrane rather than to the specific inhibition of carrier-mediated transport. Taken together, the results demonstrate that barley mesophyll vacuoles are constitutively equipped with a directly energized carrier that transports tetrapyrrolic catabolites of chlorophyll into the vacuole.

The human multidrug resistance-associated protein functionally complements the yeast cadmium resistance factor 1

A Saccharomyces cerevisiae strain with a disrupted yeast cadmium resistance factor (YCF1) gene (DTY168) is hypersensitive to cadmium. YCF1 resembles the human multidrug resistance-associated protein MRP (63% amino acid similarity), which confers resistance to various cytotoxic drugs by lowering the intracellular drug concentration. Whereas the mechanism of action of YCF1 is not known, MRP was recently found to transport glutathione S-conjugates across membranes. Here we show that expression of the human MRP cDNA in yeast mutant DTY168 cells restores cadmium resistance to the wild-type level. Transport of S-(2,4-dinitrobenzene)-glutathione into isolated yeast microsomal vesicles is strongly reduced in the DTY168 mutant and this transport is restored to wild-type level in mutant cells expressing MRP cDNA. We find in cell fractionation experiments that YCF1 is mainly localized in the vacuolar membrane in yeast, whereas MRP is associated both with the vacuolar membrane and with other internal membranes in the transformed yeast cells. Our results indicate that yeast YCF1 is a glutathione S-conjugate pump, like MRP, and they raise the possibility that the cadmium resistance in yeast involves cotransport of cadmium with glutathione derivatives.

A model for the antiphospholipid antibody syndrome: monoclonal antiphosphatidylserine antibody induces intrauterine growth restriction in mice

OBJECTIVE

Antiphospholipid antibodies are associated with clinical intrauterine growth restriction. In this study we investigated whether immunoglobulin M monoclonal antibodies against phosphatidylserine or cardiolipin or cross-reactive with both phospholipids would induce intrauterine growth restriction in an experimental model of the antiphospholipid antibody syndrome.

STUDY DESIGN

Balb/c or CD-1 mice were injected intraperitoneally on day 8 of pregnancy with three immunoglobulin M monoclonal antibodies that differentiated between cardiolipin- and phosphatidylserine-dependent antigens or with control immunoglobulin M monoclonal antibodies against irrelevant antigens. The animals were killed on day 15 of pregnancy and placental and fetal weights were measured.

RESULTS

Monoclonal antibody 3SB9b, which reacted in enzyme-linked immunosorbent assays with phosphatidylserine but not cardiolipin, induced a significant reduction in both fetal and placental weights. Monoclonal antibodies BA3B5C4, which was cross-reactive with cardiolipin and phosphatidylserine, and D11A4, which reacted with cardiolipin, did not alter fetoplacental weights.

CONCLUSION

An antiphospholipid antibody that reacts with phosphatidylserine induces significant fetal and placental intrauterine growth restriction in a mouse model for the antiphospholipid antibody syndrome, but those that react with cardiolipin do not.

The tonoplast-associated citrate binding protein (CBP) of Hevea brasiliensis. Photoaffinity labeling, purification, and cloning of the corresponding gene

A detailed comparison of citrate uptake into the vacuole-like lutoids of rubber tree (Hevea brasiliensis Muell. Arg.) and of malate and citrate transport into barley (Hordeum vulgare L.) vacuoles revealed very similar transport specificities. In order to identify proteins mediating the transport, two photoreactive analogues (N'-(2-hydroxy-5-azido)-diazo-N-3,5-benzenedicarboxylic acid and 5-azidoisophthalic acid) of malate/citrate were synthesized and found to efficiently inhibit citrate uptake into barley vacuoles (Ki = 18 microM) and Hevea lutoid vesicles (Ki = 27 microM). In vacuoles from both plant species, these photoaffinity probes specifically labeled a single protein with a molecular mass of 23.6 kDa. This citrate binding protein (CBP) was purified to homogeneity from Hevea lutoids, and amino acid sequences were determined for NH2-terminal and tryptic peptides. Using degenerate oligonucleotides of the NH2-terminal sequence, a cDNA coding for the CBP protein of Hevea was isolated. The cDNA codes for a precursor protein of 238 amino acids, containing an NH2-terminal 31-amino acid signal sequence for endoplasmic reticulum targeting, a prerequisite for vacuolar localization. The mature CBP does not show significant sequence similarities to any known primary protein structure and thus represents a member of a novel class of proteins.

Is Helicobacter pylori infection a real risk factor for gastric carcinoma?

BACKGROUND AND METHODS

That Helicobacter pylori has a role in the pathogenesis of gastric carcinoma is widely accepted, although not all doubts are definitively clarified. The purpose of this work was to detect the differences in presence and mean titer of anti-H. pylori antibodies between groups with gastric (n = 65), colonic (n = 70), and lung (n = 43) carcinoma.

RESULTS

The highest prevalence of anti-H. pylori antibodies was found in patients with pulmonary carcinoma (88.4%), which significantly surpassed (p = 0.02) that in the group with gastric carcinoma (69.2%). The groups with colonic and gastric carcinomas failed to show any difference in this respect. Mean antibody titer was significantly higher in subjects with lung carcinoma than in those with gastric carcinoma (p = 0.005). This difference was unrelated to age.

CONCLUSIONS

These results contradict the hypothesis assuming a relationship between H. pylori infection and the sequence of phenomena leading to gastric carcinoma.

Direct energization of bile acid transport into plant vacuoles

Bile acids were shown to be transported into barley mesophyll vacuoles. Uptake of the cholate conjugates taurocholate and glycocholate is strictly ATP-dependent. Uptake of taurocholate is a saturable process (Km = 40 microM) and is inhibited by vanadate but not by bafilomycin, a specific inhibitor of the vacuolar H(+)-ATPase. Together with the observation that the non-hydrolyzable ATP analog AMPPNP (5'-adenylyl beta,gamma-imidodiphosphate) does not stimulate, but rather inhibits, the ATP-dependent uptake of taurocholate, and that a 3-fold accumulation of the bile acid is observed in the presence of bafilomycin, these results suggest that taurocholate is transported into the vacuole by a primary active process as is the case for its canalicular secretion in rat liver (Nishida, T., Gatmaitan, Z., Che, M., and Arias, I. M. (1991) Proc. Natl. Acad. Sci. U. S. A. 88, 6590-6594). Taurocholate uptake is inhibited by other bile acids and is slightly stimulated by glutathione S-conjugates. The different responses of the glutathione S-conjugate (Martinoia, E., Grill, E., Tommasini, R., Kreuz, K., and Amrhein, N. (1993) Nature 364, 247-249) and the taurocholate transporters, respectively, to substrates, oligomycin, GTP, and UTP suggest the presence of at least two ATPases specifically involved in the transport of conjugates across the tonoplast. As cholate and its conjugates have so far not been reported to occur in plants, the physiological function of the novel transport ATPase described here is presently unknown.