Mid-2000s North Atlantic shift: Heat budget and circulation changes.

Prior to the 2000s, the North Atlantic was the basin showing the greatest warming. However, since the mid-2000s during the so-called global warming hiatus, large amounts of heat were transferred in this basin from upper to deeper levels while the dominance in terms of atmospheric heat capture moved into the Indo-Pacific. Here we show that a large transformation of modal waters in the eastern North Atlantic (ENA) played a crucial role in such contrasting behavior. First, strong winter mixing in 2005 transformed ENA modal waters into a much saltier, warmer, and denser variety, transferring upper ocean heat and salt gained slowly over time to deeper layers. The new denser waters also altered the zonal dynamic height gradient reversing the southward regional flow and enhancing the access of saltier southern waters to higher latitudes. Then, the excess salinity in northern regions favored additional heat injection through deep convection events in later years.

Specific IgE serum concentration is associated with symptom severity in children with seasonal allergic rhinitis.

BACKGROUND: The impact of allergen-specific and total IgE serum levels before and during the pollen season on symptom severity as well as efficacy of treatment with anti-IgE requires further delineation. METHODS: Birch and grass pollen allergic patients aged 6-17 years with seasonal allergic rhinitis (SAR) were analyzed for the association of IgE serum concentration with symptom severity and rescue medication use (combination: symptom load, SL) during the grass pollen season. Reference group A (n = 53) received placebo, while group B (n = 54) received Omalizumab (anti-IgE) monotherapy before and during the grass pollen season. RESULTS: Patients on placebo with high baseline specific grass pollen IgE (>50 kU/l) had a significantly higher SL compared with those with low IgE levels (< or =50 kU/l): SL 1.28 vs 0.61, P = 0.015. This association was nonexistent in patients treated with anti-IgE. In contrast, baseline total IgE levels did not correlate with SL in any group. Patients with anti-IgE treatment and high free total IgE levels (>16.7 ng/ml) had a significantly higher SL compared with those with low free total IgE levels (< or =16.7 ng/ml): SL 0.63 vs 0.23, P = 0.031. CONCLUSIONS: Baseline specific IgE, but not total IgE, is associated with symptom severity during the pollen season in children with SAR. Likewise, the symptom load in SAR patients with anti-IgE correlates with free total IgE levels. Although further research in larger populations is needed to confirm our findings, our data suggest that specific IgE can be used as a parameter for patient selection for this kind of treatment.

Safety and efficacy of a new extensively hydrolyzed formula for infants with cow's milk protein allergy.

Cow's milk protein allergy (CMPA) is best treated by complete elimination of cow's milk from the diet. For infants with CMPA who cannot be breast-fed, formulas based on extensively hydrolyzed proteins or on amino acids are the preferred substitutes for cow's milk-based formulas. In this study, we compared the tolerance and growth of infants with CMPA who were fed a new extensively hydrolyzed formula containing lactose (eHF) with those who were fed an amino acid formula (AAF). This was a prospective, multi-center, randomized, reference-controlled study. Seventy-seven infants <12 months old with suspected CMPA were enrolled. In 66 of these, CMPA was confirmed by oral challenge in a double-blind, placebo-controlled food challenge (DBPCFC) or by a medical history of severe allergic reaction to cow's milk and a positive skin prick test. These infants were then tested for their reaction to eHF and AAF in a DBPCFC. All infants tolerated both formulas and were randomized to receive either eHF (n = 34) or AAF (n = 32) for 180 days. Growth (weight, length, and head circumference) and tolerance [skin, gastro-intestinal, and respiratory tract symptoms of allergy] were evaluated after 30, 60, 90, and 180 days. There were no significant differences between the two groups in any of the growth measurements. Length and head circumference were similar to Euro-growth standards, but weight was slightly lower. Gastro-intestinal and respiratory tract symptoms of allergy were also similar in the two groups. However, whereas SCORAD scores for atopic dermatitis remained constant throughout the study in infants-fed eHF, there was a slight decrease in those fed AAF. Infants-fed eHF had significantly fewer incidents of vomiting than infants-fed AAF and a significantly higher frequency of soft stools. The new eHF is safe and well tolerated in infants diagnosed with CMPA.

Differential response of human naive and memory/effector T cells to dendritic cells infected by respiratory syncytial virus.

In vitro studies have contributed substantially to the understanding of immunopathology of respiratory syncytial virus (RSV)-mediated disease. In the present study we compared the effect of RSV-infected dendritic cells on the time-course of the primary and memory/effector T cell response in vitro. Cultures with uninfected dendritic cells known to elicit T helper 2 (Th2) responses and with polyinosinic-polycytidylic acid (poly-IC)-stimulated dendritic cells known to elicit Th1 responses served as controls. At day 1 after stimulation there was a high proportion of interleukin (IL)-2 and tumour necrosis factor (TNF)-alpha-producing T cells with no difference in number of producing T cells as well as concentration of secreted cytokines between RSV-infected and control cultures. However, up to day 3 generation of IFN-gamma was reduced markedly. In addition, there was a reduced proliferation in RSV cultures. At day 7 the RSV-treated cultures showed a preponderance of IL-4 generation. At days 21-24, after three rounds of restimulation, memory/effector T cells matured under the influence of RSV were still not fully polarized but in contrast to the primary response displayed a predominance of Th1 cytokines. Contact with RSV-infected HEp-2 cells inhibited proliferation of T cells; memory effector T cells were less sensitive to contact inhibition than naive T cells. In addition, RSV inhibited the stimulated rearrangement of cortical actin more effectively in naive compared to memory T cells. In summary, we have shown that RSV infection of dendritic cells has a distinct modulatory effect on the primary response and a less pronounced effect on the memory response.

Methane excess in Arctic surface water-triggered by sea ice formation and melting.

Arctic amplification of global warming has led to increased summer sea ice retreat, which influences gas exchange between the Arctic Ocean and the atmosphere where sea ice previously acted as a physical barrier. Indeed, recently observed enhanced atmospheric methane concentrations in Arctic regions with fractional sea-ice cover point to unexpected feedbacks in cycling of methane. We report on methane excess in sea ice-influenced water masses in the interior Arctic Ocean and provide evidence that sea ice is a potential source. We show that methane release from sea ice into the ocean occurs via brine drainage during freezing and melting i.e. in winter and spring. In summer under a fractional sea ice cover, reduced turbulence restricts gas transfer, then seawater acts as buffer in which methane remains entrained. However, in autumn and winter surface convection initiates pronounced efflux of methane from the ice covered ocean to the atmosphere. Our results demonstrate that sea ice-sourced methane cycles seasonally between sea ice, sea-ice-influenced seawater and the atmosphere, while the deeper ocean remains decoupled. Freshening due to summer sea ice retreat will enhance this decoupling, which restricts the capacity of the deeper Arctic Ocean to act as a sink for this greenhouse gas.

Identification of immunoreactive forms of human erythrocyte band 3 in nonerythroid cells.

Antibodies directed to the cytoplasmic domain of human erythrocyte band 3, the major integral protein of the erythrocyte membrane which is thought to be the main anchoring site of the membrane cytoskeleton, were demonstrated in the present study to react with the membrane of various nonerythroid cells, such as human leucocytes, fibroblasts or human umbilical mesenchyme cells, amniotic epithelium and vascular smooth muscle. In cultured fibroblasts staining was confined to small dots and streaks associated with both the dorsal and ventral cell membrane. In human lymphocytes band 3 antigen accompanied capping of concanavalin A binding surface receptors. The immunoreactive form of band 3 in fibroblasts was shown by immunoblotting studies to be a polypeptide of approximately 60 000 dalton. This polypeptide is immunologically and electrophoretically related to a major immunoreactive form of band 3 naturally occurring in the red blood cell membrane. Considering the recent identification in nonerythroid cells of immunoreactive forms of other major components of the erythrocyte membrane cytoskeleton, the present observation in nucleated cells of a polypeptide related to erythrocyte band 3 may indicate some of the features of erythrocyte membrane architecture are also present in nonerythroid cells.

Detection of activated lymphocyte subsets by fluorescence and MTT staining.

A double staining technique for simultaneously determinating cell surface phenotype and the degree of cell activation is described. As an activation marker, the tetrazolium dye MTT has been used. Cells were incubated for 30 min with MTT. Activated cells yielded a granular staining pattern. Upon termination of the reaction with sodium azide, a double-step immunofluorescence staining procedure using monoclonal antibodies specific for cell surface antigens was performed. The percentage of cells simultaneously displaying MTT formation and fluorescence was microscopically evaluated. Our results demonstrate that MTT staining is expressed concomitantly with the IL-2 receptor and the transferrin receptor. This method permits a simple characterization of activated T cell subsets and can be used clinically to analyse the T cell functions of patients being treated with immunosuppressive agents and patients with acquired immune deficiency syndrome.

Large-scale isolation of immature dendritic cells with features of Langerhans cells by sorting CD34+ cord blood stem cells cultured in the presence of TGF-beta1 for cutaneous leukocyte antigen (CLA).

Epidermal Langerhans cells (LCs) are a subset of immature dendritic cells (DCs) and play a key role in the initiation and regulation of T cell responses. Upon antigenic stimulation, LCs differentiate into mature DCs undergoing profound morphologic and functional changes. Studies of the biological details of this conversion process have been hampered by difficulties in generating immature dendritic cells of a defined lineage. We propose a new method of purifying homogenous immature DCs in large numbers by sorting for CLA (Langerhans-like cells) from cord-blood-derived haematopoietic progenitor cells (HPCs). Established protocols describe the generation of LCs from CD34(+) HPCs by sorting for CD1a after 5 days of culture in the presence of GM-CSF and TNF-alpha. However, the numbers of LCs obtained by this method remain within the low range. Furthermore, CD1a is also expressed on interstitial DCs. LCs but not interstitial DCs express the cutaneous leukocyte antigen (CLA). The expression of CLA by cells stimulated with TNF-alpha and GM-CSF peaks on day 10. This expression can be raised further by stimulating the cells with TGF-beta1 and omitting TNF-alpha from day 6 onwards. CLA(+) cells were isolated on day 10 by AutoMACS. Their LC phenotype was established by the presence CD207. The immaturity of Langerhans-like cells was shown by the lack of CD83 and CD208 expression as well as their lower ability to activate allogeneic naive T cells as compared to maturing dendritic cells. However, CLA(+) cells cannot be termed Langerhans cells as they do not express Birbeck granules. Compared to sorting for CD1a (on day 6), sorting for CLA (on day 10) results in isolates of higher purity (80% vs. 50%) and a yield eight times higher (4.9x10(6) vs. 6.5x10(5) cells) when using identical numbers of input cells (5x10(5) cells). This novel method guarantees large numbers of pure and functionally active immature dendritic cells.

Detection of intracellular cytokines by flow cytometry.

During the last years it has become increasingly clear that production of most cytokines is not confined to one cell type. Thus, a method to detect cytokines at the single cell level would be a helpful tool to study the contribution of different cells to cytokine production in heterogeneous cell populations. Recently, Sander et al. (1991) demonstrated that it is possible to detect intracellular cytokines by fixation with paraformaldehyde, permeabilization with saponin and subsequent indirect immunofluorescent staining using fluorescence microscopy. Here, we describe a modified method to increase the specific intracellular staining which enables us to detect IFN-gamma, IL-2 and IL-4 producing cells by single laser flow cytometry. The carboxylic ionophore monensin was used to interrupt intracellular transport processes leading to an accumulation of the cytokine in the Golgi complex. This resulting increase of the signal/noise ratio permitted us to detect weakly fluorescent cells such as IL-4 producing cells. While IL-4 was detected in approximately 1-3% of peripheral mononuclear cells from healthy donors, up to 30% of the cells produced IFN-gamma and nearly 50% IL-2 after phorbol ester and ionomycin stimulation. Microscopic and flow cytometric analysis showed a highly significant correlation. Using three-color flow cytometry it was possible to measure intracellular cytokines and cell surface markers simultaneously. Subpopulations of human T cells (e.g., CD4+ CD45R0-) producing a restricted cytokine pattern could be identified by cell surface staining and were characterized by their cytokine production. Consequently, there was no further need for cell sorting to determine cytokine producing subsets in heterogeneous cell populations. We have tested human T cell clones for intracellular cytokine production and found a high concordance to ELISA analysis of the supernatants. We conclude that detection of intracellular cytokines by flow cytometry is a rapid, easy and semiquantitative assay which may be used to study individual cells in heterogeneous populations as well as to screen homogeneous cells for their cytokine pattern. This method is particularly relevant in view of the accumulating evidence of the functional role that subsets of (T) cells may play in various diseases depending on the pattern of cytokines they produce.

A flow cytometric method for the detection of intracellular basic proteins in unseparated peripheral blood and bone marrow eosinophils.

Eosinophils and their basic proteins play a major role in allergic disease and methods are required to monitor their expression in clinical situations. In this article we describe a flow cytometric method for the detection of intracellular eosinophil cationic protein (ECP) and eosinophil peroxidase (EPO) in unseparated clinical samples. After fixation with parabenzoquinone and permeabilization with n-octyl-beta-D-glucopyranoside, the detection of intracellularly stored proteins was achieved using of monoclonal antibodies against ECP (EG1, EG2) and EPO in combination with an FITC-labeled second step antibody. Confocal microscopy was used to demonstrate the intracellular origin of the fluorescent signal. Fixation with parabenzoquinone was superior to a previously described protocol using paraformaldehyde, since it reduces non-specific binding of FITC to the basic proteins in eosinophils. Fixation and permeabilization do not alter the light scatter characteristics of eosinophils in contrast to other leukocytes and thus permit gating on eosinophils without prior purification. Furthermore, the procedure does not alter the detection of cell surface antigens on eosinophils and simultaneous measurements of surface antigens and intracellular proteins is possible. We have used different clinical samples (peripheral blood, bone marrow cells) to demonstrate differences in the expression of ECP and EPO. We conclude that the detection of intracellular eosinophil proteins by flow cytometry is a rapid, easy and semiquantitative procedure which may be used to study their expression in diseases where eosinophils are involved.

Ochratoxin A-induced tumor formation: is there a role of reactive ochratoxin A metabolites?

Ochratoxin A is a nephrotoxic and tumorigenic mycotoxin which contaminates a variety of food items, resulting in chronic human exposure. Biotransformation reactions have been implicated in the tumorigenicity of ochratoxin A. The biotransformation of ochratoxin A by cytochromes P450 and other mammalian enzymes was investigated to optimize conditions for bacterial mutagenicity testing. Metabolite formation was assessed by HPLC with UV and fluorescence detection and by LC/MS/MS. When ochratoxin A was incubated with liver microsomes from rats and mice, formation of 4R- and 4S-hydroxyochratoxin A was observed at very low rates. However, oxidation of ochratoxin A was not observed using kidney microsomes from rats and mice. Significantly higher rates of oxidation were seen in liver microsomes from rats pretreated with 3-methylcholanthrene and dexamethasone. Other reported or postulated that ochratoxin A-metabolites were not formed in detectable concentrations. Human cytochromes P450 (3A4, 1A2, and 2C9-1 Supersomes((R))) also showed very low activity with ochratoxin A (<60 fmole/min x pmol P450). Other enzyme systems used to study possible biotransformation of ochratoxin A were rat and human liver and kidney S-9 fortified with NADPH and glutathione, semipurified glutathione S-transferases, horseradish peroxidase, and soybean lipoxygenase; none of these resulted in detectable biotransformation of ochratoxin A. Using rat liver microsomes with high activity for ochratoxin A oxidation and the other enzyme systems to activate ochratoxin A for mutagenicity testing in the Ames test, mutagenicity was not observed in Salmonella typhimurium TA 100 and TA 2638. The obtained results suggest that oxidative biotransformation of ochratoxin A occurs at low rates, is catalyzed by cytochromes P450, and is unlikely to form reactive intermediates capable of binding to DNA.

Generation of reactive oxygen species and activity of platelet-activating factor acetylhydrolase in human monocyte-derived macrophages.

Monocytes were prepared from healthy human volunteers and were allowed to differentiate into macrophages by adhesion to plastic surface and cultured over 7 days in presence of either 10% fetal calf serum (FCS), human control serum or serum from hyperlipaemic patients. Hyperlipaemic serum stimulated the differentiation (measured as an increase in cellular protein and DNA content) to a higher extent when compared to control serum and FCS. With all sera a marked increase of the cellular activity of the enzyme platelet-activating factor acetylhydrolase (PAF-AH) and a tremendous decrease in the capacity of cells to generate reactive oxygen species (ROS) was observed. After seven days of culture the increase in PAH-AH activity was about 19-fold with hyperlipaemic serum, 11-fold with control serum and 6-fold with FCS. During the same period of time ROS generation measured as zymosan-induced chemiluminescence decreased by about 98% and no significant differences between the three types of serum were found. The results indicate that the activity of PAF-AH and the capacity of ROS generation which are both assumed to play an important role in the oxidation of low-density lipoproteins (LDL) and thus in the development of atherosclerosis, change in opposite direction during the differentiation of blood monocytes into macrophages, and that hyperlipaemic serum stimulates PAF-AH activity but not ROS generation.

Evaluation of respiratory syncytial virus detection by rapid antigen tests in childhood.

BACKGROUND: Rapid and reliable diagnosis is crucial for clinical management of respiratory syncytial virus infection in childhood. We assessed the performance characteristics of respiratory syncytial virus antigen immunoassays in children hospitalized for respiratory infection. METHOD: A total of 1600 children up to three years of age hospitalized for diseases potentially caused by RSV were included in the study. Nasopharyngeal secretions were obtained in a standardized manner in the first 24 hours after hospital admission and tested in parallel by PCR and rapid antigen tests for RSV. The following parameters were recorded: recruitment center, gender, age, presence of fever, rhinitis, stridor, barking cough, cough, wheezing, vomiting, disturbed eating or sleep, tachypnea, tachycardia, increased body temperature, decreased oxygen saturation, C-reactive protein, erythrocyte sedimentation rate and chest X-ray results. RESULTS: Considering PCR testing as gold standard, rapid antigen testing had a specificity of 89.9% and a sensitivity of 66.2% for all samples tested. Logistic regression analysis revealed age and recruitment center as the only parameters influencing sensitivity whereas no such influence on specificity was found. Positive likelihood ratios ranged from 4,9 to 6.9 in different age groups. Negative likelihood ratio was 0.24 (95% CI: 0.18-0.42) in children aged up to 3 months but 0.67 (95% CI: 0.53-0.84) for children older than 2 years. CONCLUSION: Rapid detection of RSV antigen in this study was useful in detection of RSV mediated disease in younger infants but shows decreasing sensitivity in children older than three months.

B cell growth factor activity in supernatants of MRL-lpr/lpr derived T cell hybridomas.

The aim of this study was to characterize B cell growth factor (BCGF) activity derived from autoimmune MLR-lpr/lpr cells. In order to obtain supernatants containing BCGF that are free of suppressor lymphokines, MLR-lpr/lpr spleen cells were fused with BW 5147 thymoma cells to form T cell hybridomas. High fusion frequencies were obtained without prestimulation in vitro indicating a high degree of preactivation in vivo. Nineteen of 172 of the resulting hybridomas produced a B cell growth factor, which induced proliferation of small B cells when co-cultured with low doses of an anti-mu antibody. Maximal augmentation of B cell proliferation by supernatants containing BCGF required low cell concentrations and the presence of factor during the initiation of the culture. These data indicate that one of the possible active components of the supernatants containing BCGF is the recently characterized lymphokine interleukin 4 (IL-4).

[Effect of insulin therapy on lipoprotein concentrations in secondary sulfonylurea treatment failures in menopause]. / Einfluss der Insulintherapie auf die Lipoprotein-Konzentrationen von Sulfonylharnstoff-Sekundärversagern in der Menopause.

The insulinization of sulfonylurea secondary failures in the menopause without essential overweight (n = 25) on an average already in the first week of treatment led to an increase of the HDL-cholesterol and to clear reductions of the triglycerides and of the atherosclerosis risk index total cholesterol/HDL-cholesterol. When a higher dose of insulin was given and in a comparable condition of glycaemia these changes continued to increase up to the 6th week of treatment, total cholesterol and LDL-cholesterol decreased. Sulfonylurea secondary failures in the menopause which were euglycaemic after a 6-week insulin therapy (n = 20) revealed at this date a higher HDL-cholesterol, lower triglycerides and a more favourable quotient total cholesterol/HDL-cholesterol as well as a shorter duration of diabetes than the female patients with more unfavourable condition of glycaemia (n = 20). Already before the induction of the insulin therapy the later on euglycaemic female patients showed an on an average lower triglyceride level than the comparative group. The reductions of total cholesterol, LDL-cholesterol and triglycerides after insulinization did not significantly differ between the two groups. On the other hand, the decrease of the quotient total cholesterol/HDL-cholesterol was significantly more distinctly characterized in the female diabetics who had become euglycaemic after a 6-week insulin therapy on account of an increase of HDL-cholesterol which is to be registered only in these patients. In sulfonylurea secondary failures in the menopause without essential overweight insulinization leads to an improvement of the lipoprotein profile, particularly when a euglycaemic metabolic conduction is achieved.

Enhanced virulence, airway inflammation and impaired lung function induced by respiratory syncytial virus deficient in secreted G protein.

BACKGROUND: Respiratory syncytial virus (RSV) infection can cause bronchial hyperresponsiveness and asthma exacerbations. In mice it results in airway inflammation and airway hyperresponsiveness. Since viral factors influencing these responses are not well defined, a study was undertaken to investigate the role of secreted G protein of human RSV in determining virulence, inflammatory responses, and changes in lung function. METHODS: BALB/c mice were infected with a spontaneous mutant of RSV deficient in secreted G protein (RSV-DeltasG) or with wild type RSV (RSV-WT). Viral titres, numbers of pulmonary inflammatory cells, and concentrations of interferon (IFN)-gamma, interleukin (IL)-4, IL-5 and IL-10 in bronchoalveolar lavage (BAL) fluid were determined. Airway function was assessed at baseline and following methacholine provocation using barometric whole body plethysmography. RESULT: Following infection with RSV-DeltasG, viral titres were increased 50-fold compared with RSV-WT. Influx of eosinophils and macrophages to the lung and concentrations of IFN-gamma and IL-10 in BAL fluid were also significantly higher following infection with RSV-DeltasG. Airway function, both at baseline and after methacholine provocation, was significantly decreased following infection with RSV-DeltasG compared with RSV-WT. CONCLUSION: Secreted G protein is likely to be a regulatory factor in RSV infection limiting infectivity of the virus, inflammatory responses in the lungs, and reduction in lung function.

[Studies on B cell activation in collagenoses]. / Untersuchungen zur B-Zellaktivierung bei Kollagenosen.

An inverse correlation between PWM and anti mu responses of peripheral blood lymphocytes, and a close relationship to clinical activity were demonstrated in 9 patients with systemic lupus erythematosus.

[Lipoprotein metabolism and beta receptor blockers]. / Lipoproteinstoffwechsel und beta-Rezeptorenblocker.

Including own results a survey is given of the side effects of beta-receptor blockers on the plasma lipoprotein metabolism. The formation of a from the coronary-preventive point of view unfavourable lipoprotein risk profile under influence of individual beta-receptor blockers, among others propranolol, seems to be connected with an inhibition of a key enzyme in the lipoprotein metabolism, the lecithin-cholesterol-acyl transferase. Talinolol does not show these side effects. It is recommended to control the triglyceride level and the HDL cholesterol before the induction and after the beginning of a therapy with beta-receptor blockers and to use talinolol instead of propranolol in pre-existing dyslipoproteinaemia or in unfavourable changes during the treatment.

[B-cell subpopulation, rosetting with mouse erythrocytes, in patients with rheumatoid arthritis]. / Untersuchungen zu einer B-Zell-Subpopulation, die mit Maus-Erythrozyten Rosetten bildet, bei Patienten mit rheumatoider Arthritis.

Inactive peripheral B-cells rosetting with mouse erythrocytes (BMR+), as well as the stimulation with anti-mu sepharose beads of peripheral mononuclear cells, are diminished in patients with active rheumatoid arthritis (RA). These data provide further evidence for a B-cell activation in active RA.