Association mapping combined with whole genome sequencing data reveals candidate causal variants for sclerotinia stem rot resistance in Brassica napus

Canola (Brassica napus) yield can be significantly reduced by the disease sclerotinia stem rot (SSR), which is caused by Sclerotinia sclerotiorum, a necrotrophic fungal pathogen with an unusually large host range. Breeding cultivars that are physiologically resistant to SSR is desirable to enhance crop productivity. However, the development of resistant varieties has proved challenging due to the highly polygenic nature of S. sclerotiorum resistance. Here, we identified regions of the B. napus genome associated with SSR resistance using data from a previous study by association mapping. We then validated their contribution to resistance in a follow-up screen. This follow-up screen also confirmed high levels of SSR resistance in several genotypes from the previous study. Using publicly available whole genome sequencing data for a panel of 83 B. napus genotypes, we identified non-synonymous polymorphisms linked to the SSR resistance loci. A qPCR analysis showed that two of the genes containing these polymorphisms were transcriptionally responsive to S. sclerotiorum infection. In addition, we provide evidence that homologues of three of the candidate genes contribute to resistance in the model Brassicaceae species Arabidopsis thaliana. The identification of resistant germplasm and candidate genomic loci associated with resistance are important findings that may be exploited by breeders to improve the genetic resistance of canola varieties.

A precursor mechanism triggering the second magnetization peak phenomenon in superconducting materials

The correlation in type-II superconductors between the creep rate S and the Second Magnetization Peak (SMP) phenomenon which produces an increase in Jc, as a function of the field (H), has been investigated at different temperatures by starting from the minimum in S(H) and the onset of the SMP phenomenon detected on a FeSe0.5Te0.5 sample. Then the analysis has been extended by considering the entire S(H) curves and comparing our results with those of many other superconducting materials reported in literature. In this way, we find evidence that the flux dynamic mechanisms behind the appearance of the SMP phenomenon in Jc(H) are activated at fields well below those where the critical current starts effectively to increase. Moreover, the found universal relation between the minimum in the S(H) and the SMP phenomenon in Jc(H) shows that both can be attributed to a sequential crossover between a less effective pinning (losing its effectiveness at low fields) to a more effective pinning (still acting at high fields), regardless of the type-II superconductor taken into consideration.

Transport mechanisms in Co-doped ZnO (ZCO) and H-irradiated ZCO polycrystalline thin films

In the present study, the electrical resistivity (ρ) as a function of the temperature (T) has been measured in polycrystalline ZnO, Co-doped ZnO (ZCO) and H irradiated ZCO (HZCO) samples, in the 300-20 K range. The achieved results show impressive effects of Co doping and H irradiation on the ZnO transport properties. The Co dopant increases the ZnO resistivity at high T (HT), whereas it has an opposite effect at low T (LT). H balances the Co effects by neutralizing the ρ increase at HT and strengthening its decrease at LT. A careful analysis of the ρ data permits to identify two different thermally activated processes as those governing the charge transport in the three materials at HT and LT, respectively. The occurrence of such processes has been fully explained in terms of a previously proposed model based on an acceptor impurity band, induced by the formation of Co-oxygen vacancy complexes, as well as known effects produced by H on the ZnO properties. The same analysis shows that both Co and H reduce the effects of grain boundaries on the transport processes. The high conductivity of HZCO in the whole T-range and its low noise level resulting from electric noise spectroscopy make this material a very interesting one for technological applications.

Transition from a uni- to a bimodal interfacial charge distribution in [Formula: see text]/[Formula: see text] upon cooling

We present a combined resonant soft X-ray reflectivity and electric transport study of [Formula: see text]/[Formula: see text] field effect devices. The depth profiles with atomic layer resolution that are obtained from the resonant reflectivity reveal a pronounced temperature dependence of the two-dimensional electron liquid at the [Formula: see text]/[Formula: see text] interface. At room temperature the corresponding electrons are located close to the interface, extending down to 4 unit cells into the [Formula: see text] substrate. Upon cooling, however, these interface electrons assume a bimodal depth distribution: They spread out deeper into the [Formula: see text] and split into two distinct parts, namely one close to the interface with a thickness of about 4 unit cells and another centered around 9 unit cells from the interface. The results are consistent with theoretical predictions based on oxygen vacancies at the surface of the [Formula: see text] film and support the notion of a complex interplay between structural and electronic degrees of freedom.

Pinning energy and anisotropy properties of a Fe(Se, Te) iron based superconductor

The measurements of DC magnetization M as a function of magnetic field (H) and time (t) have been performed in order to study the superconducting and pinning properties of a Fe(Se, Te) iron based superconductor fabricated by means of the Bridgman technique. By performing the superconducting hysteresis loops M(H) at different temperatures in the case of perpendicular and parallel field, the critical current density J_c (H) has been extracted in the framework of the Bean critical state model for both configurations. The J_c (H) curves have shown the presence of the second magnetization peak effect that causes an anomalous increase in the field dependence of the critical current density. In order to obtain the J_c anisotropy of the sample, we have performed the ratio between perpendicular and parallel critical current density values [Formula: see text] and compared its values with the literature ones. The information regarding the pinning energy U have been extracted by means of the relaxation of the irreversible magnetization M(t) in the case H∣∣c. In particular, performing relaxation measurements at different temperatures and magnetic fields, the temperature dependence of the pinning energy U(T) at different magnetic fields has been obtained showing an anomalous temperature scaling of the curves. The presence of a maximum in the U(T) curves suggests a pinning crossover at a given field and temperature H _cr(T). The H _cr(T) values have been fitted with the equation H _cr(T) = H _cr(0) (1 - T/T*) ⁿ whose results confirm the correlation between the elastic/plastic crossover and the end of the peak effect phenomenon.

ERIGO: a possible strategy to treat orthostatic hypotension in progressive supranuclear palsy? A feasibility study

Progressive supranuclear palsy (PSP) is a neurodegenerative disease of the central nervous system, presenting with different clinical phenotypes, all involving the extrapyramidal system. Orthostatic hypotension (OH) is a common symptom of cardiovascular autonomic dysfunction. OH is defined as a fall in systolic blood pressure of at least 20 mmHg and/or a fall in diastolic blood pressure of at least 10 mmHg on standing or head-up tilt. In this pilot study, we tested the feasibility and efficacy of the ERIGO® device in managing OH non-responsive to conventional treatments in a sample of patients with PSP. OH was chosen as the primary outcome, as the symptom is a serious complication in neurodegenerative disorders, challenging the rehabilitation treatment. Six patients received intensive training using ERIGO®, a robot- assisted tilt table with an integrated leg movement system that allows progressive verticalization of the patient, and application of functional electrical stimulation. In all the participants, OH improved after the training with the device, suggesting that robotic verticalization may be a feasible and effective tool in improving blood pressure stability in patients with PSP. Further studies in larger samples, also including patients with other neurodegenerative disorders associated with OH, are needed to confirm these promising results.

Differences in Blood Pressure in Infants After General Anesthesia Compared to Awake Regional Anesthesia (GAS Study-A Prospective Randomized Trial)

BACKGROUND

The General Anesthesia compared to Spinal anesthesia (GAS) study is a prospective randomized, controlled, multisite, trial designed to assess the influence of general anesthesia (GA) on neurodevelopment at 5 years of age. A secondary aim obtained from the blood pressure data of the GAS trial is to compare rates of intraoperative hypotension after anesthesia and to identify risk factors for intraoperative hypotension.

METHODS

A total of 722 infants ≤60 weeks postmenstrual age undergoing inguinal herniorrhaphy were randomized to either bupivacaine regional anesthesia (RA) or sevoflurane GA. Exclusion criteria included risk factors for adverse neurodevelopmental outcome and infants born at <26 weeks of gestation. Moderate hypotension was defined as mean arterial pressure measurement of <35 mm Hg. Any hypotension was defined as mean arterial pressure of <45 mm Hg. Epochs were defined as 5-minute measurement periods. The primary outcome was any measured hypotension <35 mm Hg from start of anesthesia to leaving the operating room. This analysis is reported primarily as intention to treat (ITT) and secondarily as per protocol.

RESULTS

The relative risk of GA compared with RA predicting any measured hypotension of <35 mm Hg from the start of anesthesia to leaving the operating room was 2.8 (confidence interval [CI], 2.0-4.1; P < .001) by ITT analysis and 4.5 (CI, 2.7-7.4, P < .001) as per protocol analysis. In the GA group, 87% and 49%, and in the RA group, 41% and 16%, exhibited any or moderate hypotension by ITT, respectively. In multivariable modeling, group assignment (GA versus RA), weight at the time of surgery, and minimal intraoperative temperature were risk factors for hypotension. Interventions for hypotension occurred more commonly in the GA group compared with the RA group (relative risk, 2.8, 95% CI, 1.7-4.4 by ITT).

CONCLUSIONS

RA reduces the incidence of hypotension and the chance of intervention to treat it compared with sevoflurane anesthesia in young infants undergoing inguinal hernia repair.

Swallowing Disturbances and Psychiatric Profile in Older Adults: The GreatAGE Study

Introduction

Several studies have reported controversial links between swallowing disturbances (SD) and psychiatric disorders in older age. The available data on the epidemiology of SD in the general population are scarce and often conflicting, because of numerous methodological factors source of possible counfounders.

Objectives

We aimed to screen the presence of psychiatric and cognitive disorders associated with SD in a random sampling of the general population ≥ 65.

Methods

A sample of 1127 elderly individuals collected in a population-based study (GreatAGE) in Castellana Grotte (53,50% males, mean age 74.1 ± 6.3 years), South-East Italy, were mailed a validated self-report questionnaire to assess SD (Eating Assessment Tool-EAT10). Psychiatric disorders and symptoms [assessed with Semi-structured Clinical Diagnostic Interview for DSM-IV-TR Axis I Disorders, Geriatric Depression Scale-30 (GDS-30) and Symptom Checklist Revised-90 (SCL-90R)], cognitive functions were assessed with a comprehensive neuropsychological battery, neurological exam, and demographics were compared in participants with and without SD using t-tests and Mann–Whitney U-test.

Results

The prevalence rates of SD amounted at 5.97%. Psychiatric diagnosis (24.22% of the sample) was statistically significant associated with SD (EAT ≥ 3, P = 0.038), and a trend was found for major depressive disorder and generalized anxiety disorder. Among SCL-90R domains, only anxiety showed a significant association with EAT ≥ 3 (P = 0.006). GDS-30 score was found to be higher in subjects with SD (P = 0.008). Cognitive functions did not differ between the two groups except for an increasing trend for Clinical Dementia Rating Scale in EAT ≥ 3 (P = 0.058).

Conclusions

These preliminary results showed an association between SD in older age and late-life major depression and anxiety disorders.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Educational level influenced the gold standard diagnosis of late-life depression in the GreatAGE study

Introduction

The validity of the 30-item Geriatric Depression Scale (GDS-30) in detecting late-life depression (LLD) requires a certain level of cognitive functioning. Further research is needed in population-based setting on other socio-demographic and cognitive variables that could potentially influence the accuracy of clinician rated depression.

Objective

To compare the diagnostic accuracy of two instruments used to assess depressive disorders [(GDS-30) and the Semi-structured Clinical Diagnostic Interview for DSM-IV-TR Axis I Disorders (SCID)] among three groups with different levels of cognitive functioning (normal, Mild Cognitive Impairment – MCI, Subjective Memory Complain – SMC) in a random sampling of the general population 65+ years.

Methods

The sample, collected in a population-based study (GreatAGE Study) among the older residents of Castellana Grotte, South-East Italy, included 844 subjects (54.50% males). A standardized neuropsychological battery was used to assess MCI, SMC and depressive symptoms (GDS-30). Depressive syndromes were diagnosed through the SCID IV-TR. Socio-demographic and cognitive variables were taken into account in influencing SCID performance.

Results

According to the SCID, the rate of depressive disorders was 12.56%. At the optimal cut-off score (≥ 4), GDS-30 had 65.1% sensitivity and 68.4% specificity in diagnosing depressive symptoms. Using a more conservative cut-off (≥ 10), the GDS-30 specificity reached 91.1% while sensitivity dropped to 37,7%. The three cognitive subgroups did not differ in the rate of depression diagnosis. Educational level is the only variable associated to the SCID diagnostic performance (P = 0.015).

Conclusions

At the optimal cut-off, GDS-30 identified lower levels of screening accuracy for subjects with normal cognition rather than for SMC (AUC 0.792 vs. 0.692); educational attainment possibly may modulate diagnostic clinician performance.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Expression patterns of C- and N-metabolism related genes in wheat are changed during senescence under elevated CO2 in dry-land agriculture

Projected climatic impacts on crop yield and quality, and increased demands for production, require targeted research to optimise nutrition of crop plants. For wheat, post-anthesis carbon and nitrogen remobilisation from vegetative plant parts and translocation to grains directly affects grain carbon (C), nitrogen (N) and protein levels. We analysed the influence of increased atmospheric CO2 on the expression of genes involved in senescence, leaf carbohydrate and nitrogen metabolism and assimilate transport in wheat under field conditions (Australian Grains Free Air CO2 Enrichment; AGFACE) over a time course from anthesis to maturity, the key period for grain filling. Wheat grown under CO2 enrichment had lower N concentrations and a tendency towards greater C/N ratios. A general acceleration of the senescence process by elevated CO2 was not confirmed. The expression patterns of genes involved in carbohydrate metabolism, nitrate reduction and metabolite transport differed between CO2 treatments, and this CO2 effect was different between pre-senescence and during senescence. The results suggest up-regulation of N remobilisation and down-regulation of C remobilisation during senescence under elevated CO2, which is consistent with greater grain N-sink strength of developing grains.

Risk of pocket hematoma in patients on chronic anticoagulation with warfarin undergoing electrophysiological device implantation: a comparison of different peri-operative management strategies

OBJECTIVE

Periprocedural management of warfarin remains challenging in patients requiring electrophysiological device surgery. For patients at high risk of thromboembolic events, guidelines recommend bridging therapy with heparin; however, this strategy is associated with a high risk of pocket hematoma. This paper systematically reviews studies appraising the risk of pocket hematoma with different perioperative anticoagulation strategies.

METHODS

All relevant studies identified in MEDLINE/PubMed, The Cochrane Collaboration CENTRAL, clinicaltrials.org and in bibliographies of key articles. Estimates were combined using a fixed effects model. Heterogeneity was assessed by p values of χ2 statistics and I2. Publication bias was assessed by visual examination of funnel plots and by Egger test. Fifteen studies enrolling 5911 patients met all inclusion criteria and were included in this review.

RESULTS

Heparin bridging compared with no heparin was associated with increased risk of pocket hematoma (OR = 4.47, 95% CI 3.21-6.23, p < 0.00001), and prolonged hospital stay (9.13 ± 1.9 days vs. 5.11 ± 1 .39 days, p < 0.00001). Warfarin continuation was not associated with increased pocket hematoma compared to warfarin discontinuation (p = 0.38), but was associated with reduced risk of pocket hematoma compared with heparin bridging (OR = 0.37, 95% CI 0.2-0.69, p = 0.002). Thromboembolic complications were reduced with heparin bridging vs. no heparin (0.50% vs.1.07%, p = 0.02), and no significant differences were reported between heparin bridging vs. warfarin continuation (p = 0.83).

CONCLUSIONS

Heparin bridging is associated with a higher risk of pocket hematoma and a prolonged hospital stay. Perioperative continuation of warfarin reduces the occurrence of pocket hematoma compared with heparin bridging without any significant differences in thromboembolic complications.

Cerebrospinal fluid neurofilament light chain levels: marker of progression to generalized amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

To evaluate whether cerebrospinal fluid (CSF) neurofilament light chain (NFL) levels could predict the time to generalization (TTG) in amyotrophic lateral sclerosis (ALS).

METHODS

Cerebrospinal fluid NFL levels of 37 cases of sporadic ALS were measured and the time of symptom spreading from spinal or bulbar localization to both (TTG) was evaluated in all patients.

RESULTS

Kaplan-Meier analysis showed a short TTG in patients with high NFL levels (log-rank test chi-squared = 19.4, P < 0.0001). In a multivariate regression model patients with NFL levels above the median had an eight-fold higher risk of generalization (adjusted hazard ratio 7.9, 95% confidence interval 2.9-21.4, P < 0.0001) compared with those with NFL levels below the median.

CONCLUSIONS

This study shows that in sporadic ALS NFL, a marker of neurodegeneration, is correlated with TTG, a clinical intermediate parameter of survivorship.

Biofilm-dependent airway infections: a role for ambroxol?

Biofilms are a key factor in the development of both acute and chronic airway infections. Their relevance is well established in ventilator associated pneumonia, one of the most severe complications in critically ill patients, and in cystic fibrosis, the most common lethal genetic disease in Caucasians. Accumulating evidence suggests that biofilms could have also a role in chronic obstructive pulmonary disease and their involvement in bronchiectasis has been proposed as well. When they grow in biofilms, microorganisms become multidrug-resistant. Therefore the treatment of biofilm-dependent airway infections is problematic. Indeed, it still largely based on measures aiming to prevent the formation of biofilms or remove them once that they are formed. Here we review recent evidence suggesting that the mucokinetic drug ambroxol has specific anti-biofilm properties. We also discuss how additional pharmacological properties of this drug could be beneficial in biofilm-dependent airway infections. Specifically, we review the evidence showing that: 1-ambroxol exerts anti-inflammatory effects by inhibiting at multiple levels the activity of neutrophils, and 2-it improves mucociliary clearance by interfering with the activity of airway epithelium ion channels and transporters including sodium/bicarbonate and sodium/potassium/chloride cotransporters, cystic fibrosis transmembrane conductance regulator and aquaporins. As a whole, the data that we review here suggest that ambroxol could be helpful in biofilm-dependent airway infections. However, considering the limited clinical evidence available up to date, further clinical studies are required to support the use of ambroxol in these diseases.

Drug eluting stent and coronary chronic total occlusions

Chronic total occlusion (CTO) is a common finding on diagnostic coronary angiography and represents one of the most challenging lesion subset in interventional cardiology. The introduction of dedicated guidewires and the development of new techniques have led to improve the success rate in the crossing of CTO lesion while the use of bare metal stent first, and, then, the use of drug eluting stent (DES) have significantly reduced the occurrence of restenosis and the need for target lesion revascularization in short and mid-term follow-up after CTO recanalization. However, new unsolved issues about the use of DES in CTO, that might impact long-term outcome, are emerging. The aim of this article is to review the current stage of knowledge on the application of stents in the treatment of CTO, with a particular attention to DES use and to DES-related challenges.

Magnetic field and temperature dependence of the critical vortex velocity in type-II superconducting films

We study the vortex dynamics in the instability regime induced by high dissipative states well above the critical current in Nb superconducting strips. The magnetic field and temperature behavior of the critical vortex velocity corresponding to the observed dynamic instability is ascribed to intrinsic non-equilibrium phenomena. The Larkin-Ovchinnikov (LO) theory of electronic instability in high velocity vortex motion has been applied to interpret the temperature dependence of the critical vortex velocity. The magnetic field dependence of the vortex critical velocity shows new features in the low-field regime not predicted by LO.

Comparison of bronchoscopic bronchoalveolar lavage vs blind lavage with a modified nasogastric tube in the etiologic diagnosis of ventilator-associated pneumonia

OBJECTIVE

Our objective was to compare the results of a blind lavage vs a bronchoscopic-guided bronchoalveolar lavage for the etiologic diagnosis of ventilator-associated pneumonia (VAP).

DESIGN

Prospective study in consecutive patients with high probability of VAP. Every patient underwent both procedures, in a formally randomized fashion. The interpretation of quantitative cultures was done in a blind fashion.

SETTING

Single center study, with a 20 bed medical and surgical Intensive Care Unit of the University Hospital in Monterrey, Mexico.

PATIENTS

Twenty-five patients with high probability of VAP.

INTERVENTIONS

Every patient underwent blind bronchoalveolar lavage with a modified nasogastric tube, and a bronchoscopic-guided bronchoalveolar lavage.

RESULTS

Twenty-one patients underwent both procedures. Four patients were excluded due to contamination of the cultures. The quantitative cultures were compared in a paired fashion. Only two patients had discordant cultures. The correlation coefficient between the number of colonies was very high, r=0.90 (95% confidence interval [CI], 0.77-0.96; p=0.0001).

CONCLUSIONS

The blind bronchoalveolar lavage with a modified nasogastric tube is a valuable tool for the identification of etiologic agent in VAP, particularly when trained bronchoscopists or the necessary resources for bronchoscopic-guided bronchoalveolar lavage are not readily available.

[Diagnosis of acute transfusion reactions]

The erroneous transfusion of AB0-incompatible red cells may result in hemolysis and complement-mediated shock (acute hemolytic transfusion reaction, AHTR), leading to death in less than 10%. The mistake will be detected by re-checking the patient's and the blood product's identity. Evidence of the incompatible transfusion is supplied by serology and, in cases of a fatal outcome, by immunohistochemistry. Differential diagnoses to be distinguished from AHTR are other immunologically mediated events like the most important transfusion-related acute lung injury (TRALI), febrile non-hemolytic transfusion reaction (FNHTR), allergic transfusion reactions, along with a variety of nonimmunologic incidents like transfusion-transmitted bacterial infections, hypervolemia, and other rare events such as citrate reaction, air embolism, and foreign body embolism. If the outcome is lethal, the question of causality has to be answered by a comprehensive evaluation including the clinical data as well as serological, microbiological, autoptic, and histological findings.

Effect of atorvastatin on different fibrinolyis mechanisms in hypercholesterolemic subjects

BACKGROUND

Hydroxymethyl-glutaryl-CoA-reductase inhibitors (statins) reduce cardiovascular events by cholesterol lowering as well as non-lipid related actions. Among them, the modulation of fibrinolysis could play a relevant role in vascular protection. Atorvastatin is able of reducing platelet activity and thrombin generation before low-density lipoprotein cholesterol (LDL-C) decrease in hypercholesterolemic subjects in which coagulation and fibrinolysis are linked by the activation of thrombin activable fibrinolysis inhibitor (TAFI). The aim of our study was to evaluate whether atorvastatin could modulate fibrinolysis by interactions with endothelial mechanisms and thrombin generation.

METHODS

Forty-four pure hypercholesterolemic subjects (26 M, 18 F, mean age 52.7+/-13.7, LDL-C 194.8+/-9.3t mg/dl) were evaluated for plasmin-antiplasmin complexes (PAP), tissue-plasminogen acivator (t-PA) and its inhibitor (PAI-1) (ELISA), TAFI activity (HPLC), platelet P-selectin (P-sel) (cytofluorymetric detection), platelet-dependent thrombin generation (PDTG, coagulative-chromogenic method) and lipid profile at baseline and after 7, 14, 28 and 90 days of atorvastatin (10 mg/die) treatment.

RESULTS

PAP were significantly reduced at baseline in hypercholesterolemic versus control subjects (P<0.05) and were related to P-sel (P<0.01), PDTG (P<0.01) and its inhibitor (PAI-1) after venous occlusion (VO) (P<0.05). Atorvastatin induced a significant increase of PAP at T(2) related to modifications of P-sel (P<0.01) and PDTG (P<0.01) before significant LDL-C reduction (P=0.132). PAI-1 was significantly changed at T(3) with relation to LDL-C (P<0.01), Von Willebrand factor (VWF) (P<0.01) and sE-sel (P<0.05).

CONCLUSIONS

The profibrinolytic activity of atorvastatin in hypercholesterolemic subjects is related, initially, to the positive effects exerted on platelet function and thrombin generation which can modulate fibrinolysis by TAFI activity.

Restriction in the repertoire of the immunoglobulin light chain subgroup in pathological cold agglutinins with anti-Pr specificity

BACKGROUND AND OBJECTIVES

In cold agglutinin disease, monoclonal red blood cell autoantibodies, termed cold agglutinins, induce haemolysis in patients exposed to the cold. Commonly, these autoantibodies are directed against the developmentally regulated I/i blood groups. A second blood group system, the Pr system (located on glycophorins), is involved less frequently. Anti-Pr cold agglutinins recognize either alpha 2,3- or alpha 2,6-linked N-acetylneuraminic acid as the immunodominant group. Cold agglutinins of anti-I/i specificity show a remarkable restriction in their genomic repertoire of the immunoglobulin heavy and light-chain immunoglobulin-variable domain (i.e. exclusive use of VH4-34 in heavy chains). For anti-Pr cold agglutinins, preliminary data on the repertoire of the light-chain variable domain indicate a preference for the subgroup Vkappa IV. To elucidate restrictions in the light-chain variable-domain subgroup repertoire of anti-Pr cold agglutinins systematically, and to discuss these results in the context of their anti-Pr(1-3) subclassification and immunodominant sialic acid, light chains in 13 anti-Pr cold agglutinins were investigated.

MATERIALS AND METHODS

The anti-Pr light chains were isolated using temperature-dependent absorption/elution techniques. Subsequently, they were subjected to N-terminal Edman degradation, and the light chain Vkappa subgroup was affiliated using the Kabat database.

RESULTS

Five of 13 (38%) light chains belonged to Vkappa IV, five of 13 (38%) to Vkappa I and three of 13 (23%) to Vkappa III. Anti-Pr with Vkappa IV subgroup light chains exclusively recognized alpha 2,3-linked N-acetylneuraminic acid.

CONCLUSIONS

Including data from the literature, the repertoire of the light-chain variable domain in pathological anti-Pr cold agglutinins exhibits a clear bias towards the use of the single germline gene-derived subgroup, Vkappa IV (eight of 17 or 47%). The association of Vkappa IV subgroup light chain-containing anti-Pr cold agglutinins with binding to alpha 2,3-, but not alpha 2,6-linked N-acetyneuraminic acid raises speculations about a possible role of subgroup-derived determinants in anti-Pr binding.

Different effect induced by treatment with several statins on monocyte tissue factor expression in hypercholesterolemic subjects

Platelets and monocytes are involved in atherothrombosis via tissue factor expression. Moreover, they are activated in hypercholesterolemia, a classic risk factor for atherothrombosis. Cholesterol-lowering drugs (statins) reduce cardiovascular risk either by decreasing cholesterol or non-lipidic actions, such as platelet and monocyte activity. The aim of our study was to evaluate the effect of several statins on platelet and monocyte activity in hypercholesterolemic subjects. Platelet activity (P-selectin, cytofluorimetric detection), tissue factor levels (ELISA) and activity (detected in whole blood and cellular preparations by a specific clotting assay) were measured in hypercholesterolemic subjects (41 males, 23 females, aged 34-65 years, total cholesterol 6.86+/-0.60 mmol/l) treated with atorvastatin 10 mg, simvastatin 20 mg, fluvastatin 40 mg, or pravastatin 40 mg for 6 weeks. P-selectin and tissue factor expression in whole blood and isolated cells were increased in hypercholesterolemic subjects with respect to controls (all P<0.001). Simvastatin, atorvastatin, and fluvastatin reduced monocyte procoagulant activity in whole blood and P-selectin (P<0.01). Tissue factor antigen and activity in isolated cells were further reduced (all P<0.05) independently of cholesterol lowering. Pravastatin decreased tissue factor expression in whole blood in direct relationship to reduction of P-sel and cholesterol (P<0.05). Our data show a different impact of several statins on monocyte tissue factor expression in whole blood, suggesting a possible role of decreased platelet activity and a direct action on monocytes. In contrast, pravastatin decreased monocyte procoagulant activity with relation to cholesteroldependent modifications of platelet function.

Structural and functional dissection of the cytoplasmic domain of the transmembrane adaptor protein SIT (SHP2-interacting transmembrane adaptor protein)

SIT (SHP2-interacting transmembrane adaptor protein) is a recently identified transmembrane adaptor protein, which is expressed in lymphocytes. Its structural properties, in particular the presence of five potential tyrosine phosphorylation sites, suggest involvement of SIT in TCR-mediated recruitment of SH2 domain-containing intracellular signaling molecules to the plasma membrane. Indeed, it has recently been demonstrated that SIT inducibly interacts with the SH2-containing protein tyrosine phosphatase 2 (SHP2) via an immunoreceptor tyrosine-based inhibition motif (ITIM). Moreover, SIT is capable to inhibit TCR-mediated signals proximal of activation of protein kinase C. However, inhibition of T cell activation by SIT occurs independently of SHP2 binding. The present study was performed to further characterize the molecular interaction between SIT and intracellular effector molecules and to identify the protein(s) mediating its inhibitory function. We demonstrate that SIT not only interacts with SHP2 but also with the adaptor protein Grb2 via two consensus YxN motifs. However, mutation of both Grb2-binding sites also does not influence the inhibitory function of SIT. In contrast, mutation of the tyrosine-based signaling motif Y(168) ASV completely abrogates the ability of SIT to inhibit T cell activation. Co-precipitation experiments revealed that the tyrosine kinase p50(csk) could represent the negative regulatory effector molecule that binds to this motif.

Adapters in lymphocyte signalling

Adapter proteins are well recognised as important molecular switches connecting immunoreceptors with intracellular signalling pathways. However, recent data suggest that homeostasis within the lymphatic system also depends on the coordinated activities of negative regulatory adapter proteins. These prevent activation of lymphocytes in the absence of externally applied signals and regulate termination/limitation of ongoing immune responses via different mechanisms.

Networks in signal transduction: the role of adaptor proteins in platelet activation

In multicellular organisms, the translation of externally applied signals into appropriate cellular responses is mediated by a multitude of complex intracellular signalling cascades. The accurate function of these signalling pathways is based on the sound interaction of proteins of different categories such as transmembrane receptors, protein kinases, protein phosphatases and g-proteins in three-dimensional signalling complexes. During the past 10 years it has became evident that a new class of proteins termed adaptor proteins is indispensable for the assembly of these intracellular signalling scaffolds. The primary function of adaptor proteins is to mediate protein-protein and protein-lipid interactions and thus to integrate receptor-mediated signals at the intracellular level and to couple signalling receptors to cytosolic signalling pathways. In order to perform this task, adapter proteins are equipped with particular protein-protein and/or protein-lipid interaction modules allowing them to communicate with other signalling proteins. While the essential function of adaptor proteins is clearly established in a variety of cell types (e.g. immune cells), the current knowledge about their role in platelet activation is still in the beginning. Numerous adaptor proteins have been shown to be expressed in platelets and many of them seem to be involved in the assembly of signalling complexes after engagement of platelet receptors such as the collagen receptor glycoprotein VI (GPVI), thrombin receptors, integrin receptors and the GP Ib receptor. This review will focus on the functional role of the most extensively studied adaptor proteins during platelet activation.

Interaction of linker for activation of T cells with multiple adapter proteins in platelets activated by the glycoprotein VI-selective ligand, convulxin

The snake venom toxin convulxin activates platelets through the collagen receptor glycoprotein VI (GPVI)/Fc receptor gamma-chain (FcR gamma-chain) complex leading to tyrosine phosphorylation and activation of the tyrosine Syk and phospholipase Cgamma2 (PLCgamma2). In the present study, we demonstrate that convulxin is a considerably more powerful agonist than collagen or the GPVI-selective collagen-related peptide (CRP). Confirmation that the response to convulxin is mediated solely via Syk was provided by studies on Syk-deficient platelets. The increase in phosphorylation of the FcR gamma-chain is associated with marked increases in tyrosine phosphorylation of downstream proteins including Syk, linker for activation of T cells (LAT), SLP-76, and PLCgamma2. The transmembrane adapter LAT coprecipitates with SLP-76 and PLCgamma2, as well as with a number of other adapter proteins, some of which have not been previously described in platelets, including Cbl, Grb2, Gads, and SKAP-HOM. Gads is constitutively associated with SLP-76 and is probably the protein bridging its association with LAT. There was no detectable association between Grb2 and SLP-76 in control or stimulated cells, suggesting that the interaction of LAT with Grb2 is present in a separate complex to that of LAT-Gads-SLP-76. These results show that the trimeric convulxin stimulates a much greater phosphorylation of the FcR gamma-chain and subsequent downstream responses relative to CRP and collagen, presumably because of its ability to cause a greater degree of cross-linking of GPVI. The adapter LAT appears to play a critical role in recruiting a number of other adapter proteins to the surface membrane in response to activation of GPVI, presumably at sites of glycolipid-enriched microdomains, enabling an organized signaling cascade that leads to platelet activation.

Passenger lymphocyte syndrome with severe hemolytic anemia due to an anti-Jk(a) after allogeneic PBPC transplantation

BACKGROUND

After allogeneic peripheral blood progenitor cell (PBPC) transplantation, a patient developed a severe hemolytic transfusion reaction due to passenger lymphocyte syndrome.

CASE REPORT

A 50-year-old woman with secondary acute myeloid leukemia transforming from a myelodysplastic syndrome received an ABO-compatible PBPC graft from her HLA-identical sister. For prophylaxis of GVHD, the patient was treated with cyclosporine and methotrexate. Eighteen days after the transplant, the patient experienced a severe hemolytic transfusion reaction due to an alloantibody (anti-Jk(a)) produced by donor lymphocytes.

RESULTS

The patient was typed as group A, Jk(a+) before transplantation; the donor was typed as group A, Jk(a-). On Day 18 after transplantation, the immunohematologic screening revealed a positive DAT (C3d 3+) and an alloanti-Jk(a). Hemolysis in the patient at that time was indicated by a drop in the Hb and an increase in the LDH level (maximum, 592 IU/L on Day 23).

CONCLUSION

The course of hemolysis and the time of appearance of an alloantibody in this patient meet the criteria for passenger lymphocyte syndrome. In most cases, this syndrome is triggered by ABO system antibodies. This is the first reported case of passenger lymphocyte syndrome after PBPC transplantation that was due to an alloantibody that did not belong to the ABO system.

[Increase of post-infection cold agglutinins after infection with Mycoplasma pneumoniae, varicella-zoster and rubella virus]

Cold agglutinins (CA) are observed during acute infections as transiently occurring postinfection autoantibodies directed against erythrocyte antigens. Distinct infectious agents induce CA of distinct specificity. A common association is the infection with Mycoplasma pneumoniae and the production of CA with anti-I specificity. In infections with varicella-zoster virus (VZV) and rubella virus (RV) a few cases of CA appearance are reported, all of them showing specificity for the Pr antigens. We examined the frequency of CA with the anti-Pr specificity in patients suffering from acute infections with VZV and RV (table 1). The known association of anti-I in about 70% of the cases with acute Mycoplasma pneumoniae infection is confirmed by our results. The occurrence of CA in infections with VZV and RV is a rare event. Based on published data, the specificity of these CA apparently is anti-Pr. Three of 5 anti-Pr examples were found in newborns with rubella embryopathy. Possibly, anti-Pr can be observed more frequently in these patients compared to adults.

Case report: anti-Coa in a Co-(a+)-typed patient with chronic renal insufficiency

The recently identified molecular structure of the Colton blood group system is characterized by an amino acid substitution at position 45 (Colton a: alanine, Colton b: valine) of the archetypical water channel protein Aquaporin-1 (AQP1), which regulates water homeostasis in the erythrocyte membrane and in the proximal tubule of the nephron. We identified a patient with the unique constellation of an antibody with the specificity anti-Coa and the Co (a+) phenotype. The serological antigen typing was confirmed by molecular typing with PCR-RFLP. The antibody has to be interpreted as an antibody against a partial Colton a antigen or as an autoantibody despite a negative direct antiglobulin test (DAT). The patient is suffering from chronic renal insufficiency of unknown origin, rising speculation about a pathophysiological relationship between the serological constellation and the clinical disease under the aspect of localization of the Colton antigens on AQP1.

Routine rhesus-D genotyping in amniotic fluid: analysis of exon 10 versus intron 4 by polymerase chain reaction

Both the exon 10 and the intron between exons 4 and 5 of the Rh-D gene were analyzed in DNA from amniotic cells by polymerase chain reaction (PCR) in order to determine the fetal Rh-D status. Residual (0.3-2 ml) samples of amniotic fluid obtained by diagnostic amniocentesis in Rh-D-negative women were analyzed. It is important to standardize the sampling and preanalytical storage and to optimize DNA extraction procedures as well as the detection of PCR products for maximal sensitivity. Genotyping was successful in approximately 90% (229 of 256) of amniotic fluid samples tested. Consistent Rh-D results were obtained by both methods in all 229 typed samples with a single exception. Our experience demonstrates that routine genotyping of the Rh-D blood group in small volumes of amniotic fluid (0.5-2 ml) is feasible. Its validity is currently tested by comparison of the prenatal genotype with the serotype of the newborn.

Enhancement of Sia-lb1 antigenicity by sulphur-containing substituents at C-5 of free N-acetylneuraminic acid

The Sia-lb1 epitope, recognized by anti-Sia-lb1 cold agglutinins, is unique since it is represented by the alpha-N-acetylneuraminic acid (alpha NeuNAc) monosaccharide. Chemical modifications of the chain at C-5 of alpha NeuNAc have shown that the natural 2-carbon and the artificial 3-carbon chains are optimal for anti-Sia-lb1 binding. Sia-lb1 antigenicity of alpha NeuNAc could be tenfold enhanced by replacement of the carbonyl oxygen by sulphur. The structural requirements of the Sia-lb1 epitope for optimal antibody binding were identified.

The expanding role of quantitative structure-activity relationships (QSAR) in toxicology

Quantitative structure-activity relationships (QSAR) have found wide use in correlating the bioactivity of all kinds of organic compounds with all kinds of biological entities. So many QSAR have been published that it is time for a new phase of study, that of comparative QSAR. From our current database of about 6000 QSAR illustrative examples are discussed.

Increased aggregation with normal surface charge and deformability of red blood cells in children with nephrotic syndrome

Hemorheological risk factors for thromboembolic disease were evaluated in 25 pediatric patients with idiopathic nephrotic syndrome (NS). In patients with increased proteinuria (greater than 100 mg/m2/24 h) red blood cell (RBC) aggregation and plasma viscosity were significantly increased when compared with patients in remission (less than 100 mg/m2/24 h) and with healthy controls. RBC surface charge was normal during increased proteinuria and remission. RBC aggregation correlated positively with plasma viscosity, fibrinogen, alpha 2-macroglobulin, immunoglobulin M, and the degree of proteinuria, and negatively with plasma albumin levels. RBC aggregation showed no correlation to RBC surface charge. Hematocrit and RBC deformability (rheoscope) were similar in both patient groups and in controls. Increased RBC aggregation and plasma viscosity may contribute to the increased risk of venous thromboembolism in NS.