Automated sampling device for monitoring intracellular metabolite dynamics

An automated sampling device coupled to a stirred tank reactor was developed for monitoring intracellular metabolite dynamics. Sample flasks fixed in transport magazines were moved by a step engine in a way that each sample flask was filled within 220 ms, resulting in a sampling rate of 4.5 s-1. Rapid inactivation of the metabolism was achieved by spraying the samples into 60% methanol at -50 degrees C. After centrifugation of the quenched cells at -20 degrees C the metabolites were extracted with perchloric acid and analyzed biochemically or with HPLC. The automated sampling device was applied for investigation of the intracellular metabolite dynamics of glycolysis in Escherichia coli after rapid glucose addition to a glucose-limited steady-state culture. For the first time oscillations of intracellular metabolite concentrations like glucose-6-phosphate, phosphoenolpyruvate, glyceraldehyde 3-phosphate, dihydroxyacetonphosphate, 3-phosphoglycerate, and pyruvate were quantified on a subseconds to seconds scale in E. coli. As an example, the kinetics of the decomposition of fructose 1, 6-bisphosphate to glyceraldehyde 3-phosphate and dihydroxyacetonphosphate were investigated by use of a well-known mechanistic kinetic model and the measured in vivo metabolite dynamics.

Contraception and the risk of type 2 diabetes mellitus in Latina women with prior gestational diabetes mellitus

CONTEXT

Effective contraception is essential in women with prior gestational diabetes mellitus (GDM) but should not increase their already substantial risk of developing type 2 diabetes.

OBJECTIVE

To determine whether exposure to low-dose oral contraceptives increases the risk of developing type 2 diabetes mellitus in women with recent GDM.

DESIGN

Retrospective cohort study of 904 Latinas with GDM who gave birth between January 1987 and March 1994, in whom postpartum diabetes was excluded at 4 to 16 weeks post partum.

INTERVENTIONS

At their initial postpartum visit, 443 women selected a nonhormonal form of contraception, 383 received a low-dose, estrogen-progestin combination oral contraceptive (OC), and 78 breast-feeding women received the progestin-only OC. When breast-feeding ended, patients initially taking progestin-only OCs were switched to combination OCs. Patients were followed up periodically with oral glucose tolerance tests for up to 7 1/2 years.

MAIN OUTCOME MEASURES

Person time was used to compute unadjusted average annual incidence rates of developing diabetes mellitus, as defined by the National Diabetes Data Group Criteria. Survival analysis was used to compute the unadjusted cumulative incidence rates and adjusted relative risks of diabetes mellitus.

RESULTS

The unadjusted average annual incidence rates of type 2 diabetes mellitus were 8.7%, 10.4%, and 26.5%, respectively, for patients using nonhormonal forms of contraception, combination OCs, and progestin-only OCs. Cumulative incidence rates were virtually identical for patients with uninterrupted use of combination OCs and nonhormonal forms of contraception, but patients using progestin-only OCs developed diabetes mellitus more rapidly during the first 2 years of use. After adjustment for potential confounding factors, the use of progestin-only OCs almost tripled the risk of type 2 diabetes mellitus compared with equivalent use of low-dose combination OCs (adjusted relative risk, 2.87; 95% confidence interval, 1.57-5.27). The magnitude of this risk increased with duration of uninterrupted use.

CONCLUSION

Progestin-only OCs were associated with an increased risk of diabetes in breast-feeding Latinas with recent GDM and probably should be prescribed with caution, if at all, in these women. Long-term use of low-dose combination OCs did not increase the risk of type 2 diabetes compared with use of nonhormonal contraception. Thus, combination OCs do not appear to increase the risk of diabetes in non-breast-feeding women with recent GDM.

Incidence and outcome of traumatic brain injury in an urban area in Western Europe over 10 years

INTRODUCTION

Valid epidemiological data on incidence and outcome of traumatic brain injury (TBI) show great variability. A study on incidence, severity and outcome of TBI was conducted in an urban area of one million inhabitants.

MATERIALS AND METHODS

130,000 prehospital emergencies were screened for TBI.

INCLUSION CRITERIA

Glasgow Coma Scale (GCS) score <or=8 and/or Abbreviated Injury Scale for head injuries (AIS(head)) score >or=2 with confirmed TBI via appropriate diagnostics.

RESULTS

Annual incidence was 7.3/100,000. Overall mortality rate was 45.8%: 182 (28%) were prehospital deaths, 116 (17.8%) patients died in hospital. Two hundred and fourteen of 352 (60.8%) surviving patients were sufficiently rehabilitated at discharge [Glasgow Outcome Scale (GOS) score = 1], but 138 patients (39.2%) survived with persisting deficits. GOS was associated with initial GCS and AIS(head).

CONCLUSION

The incidence of TBI was lower compared to the literature. The overall mortality was high, especially prehospital and early in-hospital mortality rates.

Low T3-syndrome and nutritional status as prognostic factors in patients undergoing bone marrow transplantation

Bone marrow transplantation is known to be associated with considerable morbidity and mortality. The aim of this study was to determine the influence of nutritional status and development of sick euthyroid syndrome as prognostic factors for outcome after BMT. In 100 patients who underwent transplantation the following parameters were assessed before and at day 14 and 28 after transplantation: anthropometric data (body weight, body mass index, body composition, grip strength), rapid turnover proteins transferrin and prealbumin, T4, T3, free T4, reverse T3, thyroid-stimulating hormone and thyroglobulin. Following bone marrow transplantation, 22 patients died in the short-term follow-up (group A) before day 140 after BMT, 21 patients died during further follow-up between days 140 and 365 (group B) and 57 patients survived longer than 365 days (group C). All patients experienced a significant decrease of transferrin and T3, accompanied by an increase of rT3 and rT3/T3 ratio at day 14 after BMT. At day 28 after BMT, patients in group C showed recovery from these changes with an increase of transferrin and a fall in rT3 and the rT3/T3-ratio, which was not seen in patients who died during further follow-up (groups A and B). The observed changes were independent of other prognostically relevant factors (type of disease, HLA-match, immunosuppression). Impaired nutritional status and development of a sick euthyroid syndrome, without tendency to recovery, are associated with a higher probability of fatal outcome after bone marrow transplantation and have prognostic relevance in this group of patients.

Quantitative studies on T cell diversity. II. Determination of the frequencies and Lyt phenotypes of two types of precursor cells for alloreactive cytotoxic T cells in polyclonally and specifically activated splenic T cells

Two different limiting dilution systems have been applied to compare precursor frequencies of alloreactive cytotoxic T cells (CTL-P) in the polyclonally and specifically activated lymphocyte populations and in selected Lyt T cell subsets. Both systems make use of T cell growth factor for T cell expansion but differ with respect to the activation step in that lymphocytes are either activated directly with allogenetic stimulator cells or are sensitized polyclonally with concanavalin A (Con A) in bulk culture before their expansion under limiting dilution conditions. In polyclonally activated C57BL/6 lymphocyte populations, two types of CTL-P specific for H-2d alloantigens could be identified: a frequent set with a frequency of 1/100-1/300, and a rare set with a frequency of 1/2,000-1/8,000. In contrast, only a single CTL-P set was found in specifically activated populations with a frequency similar to that of the frequent CTL-P found on Con A blasts. In Con A blasts, the frequent at higher cell concentrations by suppressor T cells, whereas rare CTL-P were insensitive to this suppressive mechanism. Whereas in specifically activated T cells, the predominant CTL-P phenotype was Lyt-123, the predominant Lyt phenotypes for the frequent and the rare CTL-P found in Con A blasts were Lyt-123 and Lyt-123, respectively, which suggests that they represent primary and secondary CTL-P, respectively. The results are discussed with respect to previous reports on the involvement of Lyt T cell subsets in the generation of cytotoxic responses and their regulation by T suppressor cells.

Recurrent head and neck cancer: retreatment of previously irradiated areas with combined chemotherapy and radiation therapy-results of a prospective study

PURPOSE

To prospectively test the effectiveness of combined chemotherapy and radiation therapy for recurrent head and neck cancer.

MATERIALS AND METHODS

In 32 patients, external-beam radiation therapy (2 Gy/d) was administered as a 5-day course with simultaneous hydroxyurea (1.5 g/d orally) and 5-fluorouracil (300 mg/m(2)/d bolus), followed by 9 days of rest. This cycle was repeated until a cumulative soft-tissue radiation dose of 110 Gy (including prior radiation therapy) was reached.

RESULTS

At a median follow-up of 18 months, three patients were alive, and 29 had died. The overall 1-year survival rate was 39%. The overall response rate was 41% (13 patients). Acute toxicity was low. According to World Health Organization and Radiation Therapy Oncology Group criteria, there were three cases of grade 3 mucositis or dermatitis and three cases of grade 3 or 4 neutropenia. Three patients had grade 3 late effects: one oral trismus, one jugular venous thrombosis, and one cerebral stroke.

CONCLUSION

The combination of simultaneous 5-fluorouracil and hydroxyurea infusion and local reirradiation is feasible for retreatment of recurrent head and neck tumors. This regimen provides short-term tumor control in most patients and long-term control in a few patients.

Binding, uptake, and transport of hypericin by Caco-2 cell monolayers

The biological evaluation of hypericin in various test models is hampered by its very poor water solubility. In the present study cyclodextrin formulations and liposomal preparations were investigated for improved delivery and solubility of hypericin in aqueous buffer systems. Caco-2 cells, grown to tight monolayers on 96-well tissue culture plates as well as on Transwell polycarbonate filters, were used to study the membrane binding and the epithelial transport of hypericin. Cumulative transport of hypericin, which could not be measured without the use of cyclodextrins, in apical-to-basolateral direction from cyclodextrin-hypericin buffer solutions was 3-5% at 37 degrees C and approximately 0.12% at 4 degrees C after 5 h. After an incubation time of 1 h at 37 and 4 degrees C, 12.7% +/- 2.6% and 6.5% +/- 0.8%, respectively, of hypericin were found to be bound to or taken up by Caco-2 cells. Liposomal formulations markedly increased the solubility of hypericin in Krebs-Ringer buffer, but there was no effect observed on the binding and transport of hypericin delivered by liposomes in the Caco-2 cell model. Due to the fluorescence properties of hypericin, its interaction with the cells could be visualized by confocal laser scanning microscopy. The results indicate that a significant accumulation of the drug in the cell membrane and the cell nucleus membrane takes place. We conclude that hypericin is absorbed through the intestinal epithelium by passive transcellular diffusion and that increasing its solubility by cyclodextrin appears as a promising approach to increase its oral bioavailability for pharmaceutical formulations.

No evidence of p53 allele-specific predisposition in human papillomavirus-associated cervical cancer

The potential association of distinct polymorphisms of the tumor suppressor gene p53 with an increased susceptibility to malignant transformation has been reported for various cancer entities. Most recently, p53 protein containing an arginine residue in codon 72 was shown to be more effectively degraded by the E6 oncoprotein of human papillomavirus (HPV) than the corresponding proline isoform in cervical carcinoma cells. Additionally, a seven times higher risk of cervical cancer for Arg homozygotes was suggested. We set out to confirm this allele-specific predisposition on a larger population, comprising 87 cervical cancer and 151 normal control samples. However, there was no significant difference in the observed frequencies of homozygous Arg genotypes in cervical cancer patients (52.8%) and normal controls (55.7%). Furthermore, the prevalence of the Arg/Arg allelotype did not vary between HPV+ (n = 75) and HPV- (n = 12) carcinoma samples. Thus, our investigation of a larger set of clinical samples does not support the proposed association of any polymorphic status of p53 at codon 72 with an elevated risk for cervical cancer.

Allogeneic bone marrow transplant or second autograft in patients with acute leukemia who relapse after an autograft. Acute Leukaemia Working Party of the European Group for Blood and Marrow Transplantation (EBMT)

Among 2752 patients with acute leukemia who had recurrent leukemia after autograft in remission and were reported to the EBMT, 94 underwent an allogeneic bone marrow transplant and 74 received a second autograft. Recipients of HLA-mismatched related or unrelated bone marrow had an increased transplant-related mortality (TRM, P = 0.017) and a decreased leukemia-free survival (LFS, P = 0.03), compared to recipients of HLA matched related or unrelated bone marrow. Outcome in recipients of HLA-compatible related or unrelated bone marrow was compared to those receiving a second autograft. TRM at 2 years was 51 +/- 8% in recipients of matched allografts and 26 +/- 6% following a 2nd autograft (P < 0.05). Two-year LFS was 27 +/- 7% and 35 +/- 6% in the two groups, respectively (NS). Multivariate analysis in these two groups showed that TRM was increased in patients who were in 2nd or later remission at 1st autograft (P < 0. 05) and allograft recipients (P < 0.05). Relapse was more common in patients with ALL (P < 0.001), above 25 years of age (P < 0.02), autograft performed later than 1991 (P < 0.05), and in second autografts (P < 0.05). LFS was decreased in patients >25 years of age (P < 0.01), if the interval from first autograft to relapse was 8 months or less (P < 0.01) and if TBI was used at first autograft (P < 0.05).

Neutrophil adhesion to histamine stimulated cultured endothelial cells is primarily mediated via activation of phospholipase C and nitric oxide synthase isozymes

OBJECTIVE AND DESIGN

In order to understand the underlying mechanism of histamine stimulated inflammatory responses, histamine receptor subtypes and signal transduction pathways by which histamine mediates the stimulation of neutrophil adhesion to endothelial cells has been studied in vitro.

MATERIAL

Human neutrophils and human umbilical vein endothelial cells.

TREATMENT

Confluent human endothelial cell layer were incubated with histamine (1 mM), H1, H2 or H3 receptor agonists: fluorophenylhistamine (10 microM), amthamine (10 microm), methylhistamine (10 microM), respectively. Ten minutes prior to histamine (1 mM) stimulation H1, H2 or H3 receptor antagonists (dimethindene, 100 microM; famotidine, 1OO microM, thioperamid 100 microM, respectively) were added. Histamine stimulated signal transduction pathways were inhibited by adding phospholipase C inhibitor 2-nitro-4-carboxyphenyl N,N-diphenylcarbamat (200 microM), adenylate cyclase inhibitor 9-(2 tetrahydrofuryl)adenine (80 microM), nitric oxide synthase isozymes inhibitor S-ethylisothiourea (1 microM) or guanylate cyclase inhibitor (LY 83583; 10 microM). Neutrophil adhesion was monitored at 30, 60, 90, 120, 150, 180 and 210 min.

METHODS

Neutrophil adhesion to endothelial cells was quantified by analysing alkaline phosphatase activity.

RESULTS

Histamine stimulation of endothelial cells resulted in a biphasic time and concentration dependent pattern of neutrophil adhesion. This pattern of neutrophil adhesion was mimicked by stimulation of endothelial cells with H1 or H2 agonists. Stimulation of endothelial cells with an H3 agonist had no effect on neutrophil binding. Inhibition of phospholipase C (PLC), nitric oxide synthase isozymes (NOS) or guanylate cyclase (GC) resulted in a significant decrease of neutrophil binding to histamine or agonist stimulated endothelial cells. An increase of neutrophil binding to unstimulated or to agonist stimulated endothelial cells was observed during inhibition of adenylate cyclase.

CONCLUSIONS

Our results suggest that histamine stimulated neutrophil adhesion is due to H1 and H2 receptor mediated activation of PLC, NOS and GC. Increase of cAMP concentration seems to mediate an inhibitory effect on PMN adhesion to endothelial cells.

Histamine induced homologous and heterologous regulation of histamine receptor subtype mRNA expression in cultured endothelial cells

Histamine has been proposed to play an important role in early inflammatory responses, based on studies documenting the effects of histamine on vasodilation and permeability of microvascular endothelium, as well as histamine-stimulated neutrophil adhesion to endothelial cells. The complex and heterogeneous biological mechanisms of histamine-mediated responses are not yet completely characterized. One of the factors defining inflammatory responses stimulated by histamine might be the distribution and density of receptor subtypes on cell membranes. The aim of this study was to assess whether the regulation of histamine receptor mRNA levels represents a control point in histamine-stimulated processes. Histamine-induced regulation of histamine receptor subtype expression was studied in vitro by semiquantitative RT-PCR analysis of total RNA extracted from stimulated and unstimulated endothelial cells. The time dependency and extent of histamine induced down-regulation varied between the H1 and H2 receptor message. The rapid decrease of H2 receptor mRNA lasted for 24 h. On the other hand, the less-pronounced reduction of H1 mRNA was transient and returned to control values after 12 h of histamine stimulation. The H2 receptor message was mainly down-regulated by activation of the H1 receptor protein. Down-regulation of the H1 receptor message seemed to be a net result of H1 and H2 receptor activation. This is the first report demonstrating a complex pattern of homologous and heterologous regulation of histamine receptor expression. These findings reveal new insight into the potential diversity of the mechanism involved in processing information via stimulation of multiple G-protein-linked pathways.

Chemokines and interleukin-18 are up-regulated in bronchoalveolar lavage fluid but not in serum of septic surgical ICU patients

Our objective was to investigate the levels of chemokines (MIP1-alpha, MCP-1, and Gro-alpha), Interleukin-18 (IL-18), and Interleukin (IL-6) in bronchoalveolar lavage (BAL) fluid and serum at the onset and ongoing states of sepsis as defined by the American College of Chest Physicians/Society of Critical Care Medicine in septic surgical ICU patients. Our summary background data was to understand the significance of compartmentalized inflammatory mediator production in an immunologically active organ (lung) in comparison with levels in the systemic circulation. The study group consisted of 20 septic patients and 10 non-septic patients on surgical ICU. At the onset of sepsis, both BAL fluid and serum samples were taken and levels of MIP-1alpha, MCP-1, GRO-alpha, IL-18, and IL-6 were measured by ELISA. Furthermore, over a subsequent 8-day period, levels of these mediators were determined in serum. In some experiments, IL-18 mRNA levels were determined in peripheral blood lymphocytes (PBL) of septic and non-septic patients. At the onset of sepsis, MIP-1alpha, MCP-1, GRO-alpha, IL-18, and IL-6 levels were significantly up-regulated in BAL fluid as compared with non-septic controls. In marked contrast, with the exception of IL-18 mRNA and IL-6 peptide, there was no increase in serum levels of inflammatory mediators determined both at the onset and during the ongoing states of sepsis. Based on the present data, monitoring levels of serum chemokines and IL-18 protein as markers of sepsis might be misleading since despite their non-detection in serum, they were highly up-regulated in the lung tissue compartment. These data might underscore the role of MIP-1alpha, MCP-1, GRO-alpha, and IL-18 in the mediation of local tissue damage. Furthermore, these findings raise the notion that mediator measurement in immunologically active organs might serve as pivotal indicators of sepsis prior to the actual fulfillment of specific clinical criteria that defines the patient as being septic.

Intracoronary enalaprilat during angioplasty for acute myocardial infarction: alleviation of postischaemic neurohumoral and inflammatory stress?

AIM

Reperfusion after myocardial ischaemia is associated with a distinct ischaemia/reperfusion injury. Since ACE-inhibition, beyond its influence on cardiac angiotensin II formation and kinin metabolism, has been shown to be cardioprotective by decreasing leucocyte adhesion and endothelin-1 (ET-1) release, we investigated the effects of intracoronary (i.c.) enalaprilat during primary angioplasty in acute myocardial infarction.

METHODS AND RESULTS

Twenty-two patients were randomized to receive i.c. enalaprilat (50 micro g) or placebo immediately after reopening of the infarct-related artery (IRA). Plasma concentrations of soluble L-selectin, P-selectin, intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), ET-1 and nitric oxide metabolite concentrations (NOx) were measured in pulmonary arterial blood. Coronary blood flow was assessed using corrected thrombolysis in myocardial infarction (TIMI) frame counts (CTFC). During reperfusion, there was a significant increase in sL-selectin, sP-selectin and ET-1 in the placebo group, which was greatly diminished by enalaprilat. Levels of sVCAM-1 and sICAM-1 were not affected in either group. CTFC in the placebo group remained higher than normal in both the IRA and nonculprit vessels, whereas myocardial blood flow improved with enalaprilat.

CONCLUSION

Enalaprilat as adjunct to primary angioplasty might be a protective approach to prevent leucocyte adhesion and the release of ET-1, thereby improving coronary blood flow.

Polyclonal anti-histamine H2 receptor antibodies detect differential expression of H2 receptor protein in primary vascular cell types

OBJECTIVE AND DESIGN

One of the factors defining cellular response might be the distribution and density of receptor subtypes on cell membranes. It was our aim to quantify and compare histamine H2 receptor expression in primary vascular cell types. We have therefore generated antibodies directed against the second extra-cellular loop of the H2 receptor.

METHODS

The specificity of polyclonal anti-H2 receptor antibodies designed for this purpose was examined by Western blot analysis and immunohistochemistry. H2 receptor expression was quantified by ELISA. Regulation of H2 receptor gene expression was analyzed by competitive RT-PCR.

RESULTS

Our results indicate that the polyclonal antibodies specifically interact with the histamine H2 receptor. Furthermore, utilizing these antibodies we were able to show significant differences in H2 receptor levels in human umbilical arterial and vein endothelial cells as well as smooth muscle cells.

CONCLUSIONS

We conclude that the antibodies generated against the extra-cellular domain of the H2 receptor are specific and can be utilized to detect and quantify H2 receptor expression. Furthermore, the significant differences in H2 receptor expression in different vascular cell types might play a critical role in defining histamine induced cellular responses during physiological or pathophysiological processes.

Lymphangiolipoma of the lower extremity: 5-year radiological follow-up after radiotherapy treatment

This report describes a lymphangiolipoma located in the extremity in a young woman. Radiotherapy effectively controlled recurrent lymphangiolipoma of the left upper leg that had been judged inoperable by limb-sparing surgical resection. In the case presented here, a dose of 50 Gy in 25 fractions over 5 weeks was employed without long-term complications after 5-year follow-up.

CT simulation in nodal positive breast cancer

BACKGROUND

A variety of solutions are used to match tangential fields and opposed lymph node fields in irradiation of nodal positive breast cancer. The choice is depending on the technical equipment which is available and the clinical situation. The CT simulation of a non-monoisocentric technique was evaluated in terms of accuracy and reproducibility.

PATIENTS, MATERIAL AND METHODS

The field match parameters were adjusted virtually at CT simulation and were compared with parameters derived mathematically. The coordinate transfer from the CT simulator to the conventional simulator was analyzed in 25 consecutive patients.

RESULTS

The angles adjusted virtually for a geometrically exact coplanar field match corresponded with the angles calculated for each set-up. The mean isocenter displacement was 5.7 mm and the total uncertainty of the coordinate transfer was 6.7 mm (1 SD). Limitations in the patient set-up became obvious because of the steep arm abduction necessary to fit the 70 cm CT gantry aperture. Required modifications of the arm position and coordinate transfer errors led to a significant shift of the marked matchline of > 1.0 cm in eight of 25 patients (32%).

CONCLUSION

The virtual CT simulation allows a precise and graphic definition of the field match parameters. However, modifications of the virtual set-up basically due to technical limitations were required in a total of 32% of cases, so that a hybrid technique was adapted at present that combines virtual adjustment of the ideal field alignment parameters with conventional simulation.

P3858High H2FPEF score is an independent predictor of adverse outcome in patients with severe aortic stenosis and preserved ejection fraction undergoing TAVR

Background

Recently, the H2FPEF score has been developed in an evidence-based approach relying on simple clinical and echocardiographic variables. It enables the identification of patients with high probability of prevalent heart failure with preserved ejection fraction (HFpEF) which is associated with a dismal prognosis. Left ventricular diastolic dysfunction, a key mechanism in HFpEF, is also a common finding in patients with severe aortic stenosis.

Objective

To assess the prognostic impact of the H2FPEF score in patients with preserved ejection fraction and severe aortic stenosis undergoing Transcatheter Aortic Valve Replacement (TAVR).

Methods

Among 1148 patients with preserved ejection fraction who received TAVR at our institution between 2013 and 2018, data for calculation of the H2FPEF score was available in 535 patients. Score variables include BMI >30 kg/m2, arterial hypertension, atrial fibrillation, pulmonary hypertension >35 mmHg, age >60 years, and elevated LV filling pressure. Patients were dichotomized according to “low” (1–5 points; n=377) and “high” H2FPEF scores (6–9; n=158). Kaplan-Meier survival curves and Cox regression analyses were used to assess the prognostic impact of H2FPEF scores. Median follow-up time was 0.3 years.

Results

TAVR patients presenting with high H2FPEF scores had higher prevalence of moderate to severe mitral regurgitation (19.4% vs. 33.6%, p<0.001) as well as tricuspid regurgitation (15.2% vs. 35.1%, p<0.001), and presented with lower stroke volume index (42.2 ml/m2 vs. 36.0 ml/m2, p<0.001) compared to those with low H2FPEF scores. All-cause mortality one year after TAVR was significantly higher in patients in the high H2FPEF score group (10.5% vs. 21.0%, p=0.0019, Figure 1). Multivariate analysis revealed a high H2FPEF score to be independently predictive for 1-year all-cause mortality (HR 2.66, 95% CI: 1.41–5.02, p=0.025). Among the single H2FPEF score variables, atrial fibrillation (HR 3.45, 95% CI: 1.86–6.40, p<0.001) and systolic pulmonary hypertension >55 mmHg (HR=2.68, 95% CI: 0.97–7.40, p=0.057) were strong independent predictors of adverse outcome.

Figure 1. All-cause mortality of patients undergoing TAVR after one year stratified by low (1–5 points) and high (6–9) H2FPEF score

Conclusion

An elevated H2FPEF score of >6 is independently predictive for mortality in patients with preserved ejection fraction undergoing TAVR for severe aortic stenosis. Our findings provide evidence that the H2FPEF score, which was meant for diagnostic use originally, is able to serve as a prognostic tool in patients with preserved ejection fraction undergoing TAVR, highlighting the adverse impact of diastolic dysfunction in patients with preserved ejection fraction and aortic stenosis.

Nitric oxide mediates histamine induced down-regulation of H2 receptor mRNA and internalization of the receptor protein (R1)

During agonist-dependent long-term stimulation of cells, histamine receptor subtypes are frequently down-regulated. However, the mechanisms underlying the modulation of receptor expression during long-term histamine stimulation have yet to be resolved. Based on our recently reported results showing an H1-mediated down-regulation of histamine H2 receptor mRNA in endothelial cells, our aim was to characterize the mechanism controlling rapid and long-term histamine-mediated modulation of H2 receptor expression in more detail. We were able to show that the histamine-induced down-regulation of H2 receptor mRNA and cell surface expression lasting for 24 h was accompanied by augmentation of the receptor protein level in the cytoplasmatic fraction of endothelial cells for this time period. Furthermore, changes in receptor protein levels in whole-cell lysate were negligible, indicating that the rapid and prolonged modulation of cell surface H2 receptor levels by histamine was regulated solely via internalization. The role of nitric oxide (NO) as a key mediator in histamine-stimulated cell responses was underlined by subsequent studies showing the attenuation of histamine-induced H2 receptor mRNA down-regulation and protein trafficking following NO synthase isozyme inhibition.