Comparison of ventricular ectopic activity during 24-hour monitoring and exercise testing in patients with coronary heart disease

The exposure of ventricular ectopic activity (VEA) by maximal exercise testing and 24-hour ambulatory monitoring was compared in 100 unselected patients with coronary heart disease. The arrhythmia was noted with exercise in 56 patients and with monitoring in 88. Repetitive forms such as couplets and ventricular tachycardia were found to be twice as frequent (40 vs. 20) with monitoring than with exercise. Patients with prior myocardial infarction had more frequent ventricular ectopic activity of a more advanced grade with both exercise and monitoring than patients with angina pectoris. Exercise exposed the grades of ectopic activity that recurred during two or more hours of the monitoring session. Of seven patients with ventricular tachycardia on exercise only four exhibited this grade with monitoring. It may be that these two methods divulge different information regarding the electrophysiologic state of the myocardium.

Volumetric measurements of bacterial cells and extracellular polymeric substance glycoconjugates in biofilms

In this study an enrichment culture developed from activated sludge was used to investigate the architecture of fully hydrated multispecies biofilms. The assessment of biofilm structure and volume was carried out using confocal laser scanning microscopy (CLSM). Bacterial cell distribution was determined with the nucleic acid-specific stain SYTO 60, whereas glycoconjugates of extracellular polymeric substances (EPS) were stained with the Alexa-488-labeled lectin of Aleuria aurantia. Digital image analysis was employed for visualization and quantification of three-dimensional CLSM data sets. The specific volumes of the polymeric and cellular biofilm constituents were quantified. In addition, gravimetric measurements were done to determine dry mass and thickness of the biofilms. The data recorded by the CLSM technique and the gravimetric data were then compared. It was shown that the biofilm thicknesses determined with both methods agree well for slow-growing heterotrophic and chemoautotrophic biofilms. In addition, for slow-growing biofilms, the volumes and masses calculated from CLSM and the biomass calculated from gravimetric measurements were also comparable. For fast-growing heterotrophic biofilms cultivated with high glucose concentrations the data sets fit to a lesser degree, but still showed the same common trend. Compared with traditional gravimetric measurements, CLSM allowed differential recording of multiple biofilm parameters with subsequent three-dimensional visualization and quantification. The quantitative three-dimensional results recorded by CLSM are an important basis for understanding, controlling, exploiting, and modeling of biofilms.

The different epidemiologic subtypes of Burkitt lymphoma share a homogenous micro RNA profile distinct from diffuse large B-cell lymphoma

Sporadic Burkitt lymphoma (sBL) can be delineated from diffuse large B-cell lymphoma (DLBCL) by a very homogeneous mRNA expression signature. However, it remained unclear whether all three BL variants-sBL, endemic BL (eBL) and human immunodeficiency virus-associated BL (HIV-BL)-represent a uniform biological entity despite their differences in geographical occurrence, association with immunodeficiency and/or incidence of Epstein-Barr virus (EBV) infection. To address this issue, we generated micro RNA (miRNA) profiles from 18 eBL, 31 sBL and 15 HIV-BL cases. In addition, we analyzed the miRNA expression of 86 DLBCL to determine whether miRNA profiles recapitulate the molecular differences between BL and DLBCL evidenced by mRNA profiling. A signature of 38 miRNAs containing MYC regulated and nuclear factor-kB pathway-associated miRNAs was obtained that differentiated BL from DLBCL. The miRNA profiles of sBL and eBL displayed only six differentially expressed miRNAs, whereas HIV and EBV infection had no impact on the miRNA profile of BL. In conclusion, miRNA profiling confirms that BL and DLBCL represent distinct lymphoma categories and demonstrates that the three BL variants are representatives of the same biological entity with only marginal miRNA expression differences between eBL and sBL.

Oxygen profiles and biomass distribution in biopellets ofAspergillus niger

Morphology of fungal pellets has a significant influence on mass transfer and turnover processes in submerged cultures. There are many reports in literature that biomass is not distributed homogeneously over the pellet radius, yet quantitative data is rare. This study presents a method for the quantification of fungal pellet structure (Aspergillus niger). Confocal laser scanning microscopy (CLSM) is used in combination with image analysis freeware (Image J). Hyphal distribution is resolved spatially in radial direction. Quantitative morphological parameters are derived from digital images especially from the peripheral regions of the pellet that are not oxygen limited. This morphological information is combined with data of microelectrode measurements in the same pellets. Results show that the morphological parameters obtained can describe the impact of pellet structure on oxygen gradients much better than average biomass density. It is concluded that CLSM and image analysis are powerful tools not only to generate valuable data for quantitative description of pellet morphology. In addition, this data may be used in mathematical models to improve predictions of mass transfer and substrate conversion in mycelial aggregates.

Selection of reference genes for normalisation of specific gene quantification data of Aspergillus niger

Aspergillus niger is a widely used expression host for homologous and heterologous protein production in biotechnological processes. In order to increase product yields, a thorough optimisation of these cultivation processes is necessary. Considering mRNA as the key molecule, which transports the genetic information between DNA and protein production side, the quantification of product specific gene expression provides useful information about product formation already on the level of transcription. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is a powerful tool to obtain data about gene transcription. However, using this technique the choice of an appropriate reference system is a crucial aspect to provide optimal data normalisation. A prominent approach is the use of so called housekeeping genes as internal references. However, validation of the usability of these reference genes is the fundamental step before starting with qRT-PCR experiments. Adequate reference genes for A. niger have not been published so far. Therefore, 10 possible candidate genes from different functional classes were selected and their applicability as internal references validated. Transcript levels of these genes were compared in sets of 9, 41 and 19 samples from diverse cultivations of A. niger. Under the chosen experimental conditions, the genes act, sarA and cox5 have been identified as genes with the most stable gene expression. The three reference genes were used to normalise qRT-PCR data for glaA gene expression which showed a high correlation with glucoamylase production in continuous cultivations.

Sex Differences in Semantic Processing: Event-Related Brain Potentials Distinguish between Lower and Higher Order Semantic Analysis during Word Reading

Behavioral studies suggest that women and men differ in the strategic elaboration of verbally encoded information especially in the absence of external task demand. However, measuring such covert processing requires other than behavioral data. The present study used event-related potentials to compare sexes in lower and higher order semantic processing during the passive reading of semantically related and unrelated word pairs. Women and men showed the same early context effect in the P1-N1 transition period. This finding indicates that the initial lexical-semantic access is similar in men and women. In contrast, sexes differed in higher order semantic processing. Women showed an earlier and longer lasting context effect in the N400 accompanied by larger signal strength in temporal networks similarly recruited by men and women. The results suggest that women spontaneously conduct a deeper semantic analysis. This leads to faster processing of related words in the active neural networks as reflected in a shorter stability of the N400 map in women. Taken together, the findings demonstrate that there is a selective sex difference in the controlled semantic analysis during passive word reading that is not reflected in different functional organization but in the depth of processing.

Discrepant NOXA (PMAIP1) transcript and NOXA protein levels: a potential Achilles' heel in mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive lymphoid neoplasm with transient response to conventional chemotherapy. We here investigated the role of the Bcl-2 homology domain 3-only protein NOXA for life–death decision in MCL. Surprisingly, NOXA (PMAIP1) mRNA and NOXA protein levels were extremely discrepant in MCL cells: NOXA mRNA was found to be highly expressed whereas NOXA protein levels were low. Chronic active B-cell receptor signaling and to a minor degree cyclin D1 overexpression contributed to high NOXA mRNA expression levels in MCL cells. The phoshatidyl-inositol-3 kinase/AKT/mammalian target of rapamycin pathway was identified as the major downstream signaling pathway involved in the maintenance of NOXA gene expression. Interestingly, MCL cells adapt to this constitutive pro-apoptotic signal by extensive ubiquitination and rapid proteasomal degradation of NOXA protein (T_½∼15–30 min). In addition to the proteasome inhibitor Bortezomib, we identified the neddylation inhibitor MLN4924 and the fatty acid synthase inhibitor Orlistat as potent inducers of NOXA protein expression leading to apoptosis in MCL. All inhibitors targeted NOXA protein turnover. In contrast to Bortezomib, MLN4924 and Orlistat interfered with the ubiquitination process of NOXA protein thereby offering new strategies to kill Bortezomib-resistant MCL cells. Our data, therefore, highlight a critical role of NOXA in the balance between life and death in MCL. The discrepancy between NOXA transcript and protein levels is essential for sensitivity of MCL to ubiquitin-proteasome system inhibitors and could therefore provide a druggable Achilles' heel of MCL cells.

Distinct resting-state perfusion patterns underlie psychomotor retardation in unipolar vs. bipolar depression

OBJECTIVE

Psychomotor abnormalities characterize both unipolar (UP) depression and bipolar (BP) depression. We aimed to assess their neurobiological correlates in terms of motor activity (AL) and resting-state cerebral blood flow (rCBF) and investigate their association in BP, UP, and healthy controls (HC).

METHOD

We enrolled 42 depressed patients (22 BP, 20 UP) and 19 HC matched for age, gender, education, income. AL and rCBF were objectively assessed with the use of wrist actigraphy and arterial spin labeling. Group differences and the association of AL and rCBF were computed.

RESULTS

Activity level was significantly reduced in patients, but no difference was found between BP and UP. Increased perfusion was found in BP compared with UP and HC, in multiple brain areas. We found positive correlations of rCBF and AL in BP and UP, in different parts of the insula and frontal regions. Only BP showed a cluster in the left precentral gyrus. In HC, only inverse correlations of AL and rCBF were found.

CONCLUSION

The differences in rCBF and in the localization of the clusters of positive AL/rCBF correlations between BP and UP suggest that different neural impairments may underlie motor symptoms in the two disorders, but finally converge in phenotypically similar manifestations.

Effective diffusivities and mass fluxes in fungal biopellets

Mass transport within biological aggregates is a key process that can determine overall turnover rates in submerged cultivations. A parameter commonly used for its description is the effective diffusion coefficient D(eff), which is highly dependent on biomass density and structure. Different approaches have been used to estimate or measure D(eff), yet the data still shows broad scattering. This study provides experimental data on effective diffusivities of oxygen within fungal pellets. A correlation is found with the hyphal gradient (dh/dr), which is a morphological parameter describing the structure of the pellet periphery. Furthermore, the dependency of D(eff) on fluid dynamic conditions at the pellet is investigated. The comparison of the results with data from literature clearly demonstrates the influence of the experimental methodology applied for determination of D(eff). Moreover, it is shown that while diffusion limitation of whole pellets is mainly a function of size, the influence of advection in the outer zone of pellets that is supplied with oxygen is actually rather high. Thus, it is concluded that the effective diffusion coefficient might not be sufficient for the description of mass transport within the pellet periphery for a broad range of realistic fluid dynamic conditions during cultivation. Nevertheless, although actual mass transport rates inside pellets are unknown, mass fluxes can be calculated on the basis of spatially resolved data of oxygen and biomass distribution within the pellet.

Comparison of spatial and temporal pattern for fMRI obtained with BOLD and arterial spin labeling

Functional magnetic resonance imaging (fMRI) is presently either performed using blood oxygenation level-dependent (BOLD) contrast or using cerebral blood flow (CBF), measured with arterial spin labeling (ASL) technique. The present fMRI study aimed to provide practical hints to favour one method over the other. It involved three different acquisition methods during visual checkerboard stimulation on nine healthy subjects: 1) CBF contrast obtained from ASL, 2) BOLD contrast extracted from ASL and 3) BOLD contrast from Echo planar imaging. Previous findings were replicated; i) no differences between the three measurements were found in the location of the activated region; ii) differences were found in the temporal characteristics of the signals and iii) BOLD has significantly higher sensitivity than ASL perfusion. ASL fMRI was favoured when the investigation demands for perfusion and task related signal changes. BOLD fMRI is more suitable in conjunction with fast event related design.

Hallucinations, thought disorders, and the language domain in schizophrenia

Auditory hallucinations and formal thought disorders are major diagnostic features of schizophrenia. From a neurobiological point of view, they are of particular interest since both can be attributed to the language domain of human communication. In the last decade, brain imaging studies have contributed to the understanding of the functional dynamics underlying these phenomena. In particular, auditory hallucinations were found to involve the regions generating inner speech as well as the primary acoustical cortex and the intrahemispheric fiber bundles connecting the left frontal with the temporal lobe. In patients with formal thought disorders, on the other hand, the left temporal language area showed structural deficits and functional abnormalities, i.e., reduced reactivity to stimulation and increased activity at rest; left frontal language regions were also hyperactive at rest but showed no structural deficits. The available evidence indicates a dynamic imbalance of the language system, triggered by subtle structural changes, as the possible common neurobiological basis of hallucinations and formal thought disorders.

Similar clinical features in follicular lymphomas with and without breaks in the BCL2 locus

Approximately 15% of follicular lymphomas (FLs) lack breaks in the BCL2 locus. The aim of this study was to better define molecular and clinical features of BCL2-breakpoint/t(14;18)-negative FLs. We studied the presence of BCL2, BCL6 and MYC breaks by fluorescence in situ hybridization and the expression of BCL2, MUM1, CD10, P53 and Ki67 in large clinical trial cohorts of 540 advanced-stage FL cases and 116 early-stage disease FL patients treated with chemotherapy regimens and radiation, respectively. A total of 86% and 53% of advanced- and early-stage FLs were BCL2-breakpoint-positive, respectively. BCL2 was expressed in almost all FLs with BCL2 break and also in 86% and 69% of BCL2-breakpoint-negative advanced- and early-stage FLs, respectively. CD10 expression was significantly reduced in BCL2-breakpoint-negative FLs of all stages and MUM1 and Ki67 expression were significantly increased in BCL2-break-negative early-stage FLs. Patient characteristics did not differ between FLs with and without BCL2 breaks and neither did survival times in advanced-stage FLs. These results suggest that the molecular profile differs to some extent between FLs with and without BCL2 breaks and support the notion that FLs with and without BCL2 breaks belong to the same lymphoma entity.

Outcome of elderly patients with diffuse large B-cell lymphoma treated with R-CHOP: results from the UK NCRI R-CHOP14v21 trial with combined analysis of molecular characteristics with the DSHNHL RICOVER-60 trial

BACKGROUND

There is an on-going debate whether 2- or 3-weekly administration of R-CHOP is the preferred first-line treatment for elderly patients with diffuse large B-cell lymphoma (DLBCL). The UK NCRI R-CHOP14v21 randomized phase 3 trial did not demonstrate a difference in outcomes between R-CHOP-14 and R-CHOP-21 in newly diagnosed DLBCL patients aged 19-88 years, but data on elderly patients have not been reported in detail so far. Here, we provide a subgroup analysis of patients ≥60 years treated on the R-CHOP14v21 trial with extended follow-up.

PATIENTS AND METHODS

Six hundred and four R-CHOP14v21 patients ≥60 years were included in this subgroup analysis, with a median follow-up of 77.7 months. To assess the impact of MYC rearrangements (MYC-R) and double-hit-lymphoma (DHL) on outcome in elderly patients, we performed a joint analysis of cases with available molecular data from the R-CHOP14v21 (N = 217) and RICOVER-60 (N = 204) trials.

RESULTS

Elderly DLBCL patients received high dose intensities with median total doses of ≥98% for all agents. Toxicities were similar in both arms with the exception of more grade ≥3 neutropenia (P < 0.0001) and fewer grade ≥3 thrombocytopenia (P = 0.05) in R-CHOP-21 versus R-CHOP-14. The elderly patient population had a favorable 5-year overall survival (OS) of 69% (95% CI: 65-73). We did not identify any subgroup of patients that showed differential response to either regimen. In multivariable analysis including individual factors of the IPI, gender, bulk, B2M and albumin levels, only age and B2M were of independent prognostic significance for OS. Molecular analyses demonstrated a significant impact of MYC-R (HR = 1.96; 95% CI: 1.22-3.16; P = 0.01) and DHL (HR = 2.21; 95% CI: 1.18-4.11; P = 0.01) on OS in the combined trial cohorts, independent of other prognostic factors.

CONCLUSIONS

Our data support equivalence of both R-CHOP application forms in elderly DLBCL patients. Elderly MYC-R and DHL patients have inferior prognosis and should be considered for alternative treatment approaches.

TRIAL NUMBERS

ISCRTN 16017947 (R-CHOP14v21); NCT00052936 (RICOVER-60).

Degradation pathways, analytical characterization and formulation strategies of a peptide and a protein. Calcitonine and human growth hormone in comparison

Peptides and proteins differ from conventional chemical entities in their sensitivity to numerous environmental factors and their susceptibility to different degradation pathways. Therefore, complex analytical methodologies are necessary to characterize their molecular entity as well as to detect and quantify the possible degradation products. The formulation of these molecules for a pharmaceutical product requires stabilization by various excipients. Most of the products are brought to market as solutions or lyophilisates. In the first part, this article presents a comparison between the degradation profile of a peptide (calcitonine) and a protein (human growth hormone), in solution and as a freeze-dried product. The various analytical methods used to characterize and identify the degradation products are reviewed and discussed. The second part contains an overview of the different formulation strategies for calcitonine and human growth hormone. Finally, the different stress conditions used to obtain stability data are discussed critically. This leads on to general comments on the design of stability studies for peptide and protein drugs as pharmaceuticals taking into consideration the official guidelines.

A recurrent glycine substitution mutation, G2043R, in the type VII collagen gene (COL7A1) in dominant dystrophic epidermolysis bullosa

Dystrophic epidermolysis bullosa (DEB) is caused by mutations in the type VII collagen gene (COL7A1). Nearly all cases of dominant DEB are caused by glycine substitution mutations occurring within the triple helical region of type VII collagen, and most of the mutations are unique to individual families. In this study, we identified a patient of Hispanic-Mexican origin with a mild form of DEB, which resulted from a de novo dominant glycine substitution, G2043R, in exon 73 of COL7A1. We also investigated a Scottish family with a three-generation pedigree of dominant DEB, in whom the same glycine to arginine substitution mutation was demonstrated. This particular mutation has also been detected previously in three other families with dominant DEB: one Italian, one Hungarian and one Norwegian. Given the widespread geographical distribution of this mutation and the demonstration of its occurrence as a de novo event, G2043R therefore represents the first example of a mutational hotspot in dominant DEB. Interestingly, although both the Mexican and Scottish families we studied had some clinical features in keeping with the Pasini form of the disorder, there was considerable interfamilial variability as well as intrafamilial diversity in the affected individuals.

Alimentary tract and pancreas. Stimulation of mucosal prostaglandin synthesis in human stomach and duodenum by antacid treatment

The effect of a low dose antacid treatment on mucosal prostaglandin metabolism was studied in 15 healthy volunteers. A daily dose of 46 mmol (= 138 mval) Al(OH)3 and 42 mmol (= 84 mval) Mg(OH)2 with a titrated in vitro neutralising capacity of 272 mval of H+ was given for three weeks. Total prostaglandin formation and the prostaglandin profile as well as the degradation of PGE2 were assayed by incubating homogenates of endoscopic biopsies from antral and duodenal mucosa with the precursor (14C)arachidonic acid. Total prostaglandin synthesis in antrum (623 (110) pmol/mg protein) and duodenum (432 (72) pmol/mg) was stimulated after three weeks administration of low dose antacids by 176% (p less than 0.05) and 154% (p less than 0.05), respectively. An untreated control group exhibited no significant changes. In contrast, the prostaglandin profile showed only a small increase of the prostacyclin metabolite 6-keto PGF1a (p less than 0.05) at the expense PGD2. PGE2 catabolism was unaffected. This enhanced activity of mucosal prostaglandin cyclooxygenase might represent one possible mechanism of action of a low dose antacid treatment.

Size-exclusion chromatography of plasma proteins with high molecular masses

Two different hydrophilic materials with large pores, Superose 6 and Fractogel EMD BioSec (S), which are designed for size-exclusion chromatography (SEC) of plasma proteins with high molecular masses, are tested for their performance on a preparative scale. The model mixtures are preparations of the clotting factors VIII (FVIII) and IX (FIX). A combination of a Fractogel EMD BioSec (S) column and a Superose 6 column has proved to be particularly effective for separations in a wide molecular size range, from several millions down to about 20,000. Superose 6 showed good results on a small scale as well as on a large scale, even in the molecular mass range over 1,000,000. However, recovery of FVIII clotting activity was less than 70% with this material and therefore not satisfactory. Fractogel did not perform well in terms of separation on a small scale. However, in the case of biopolymers with high molecular masses, separation was improved by using larger columns. With Fractogel, recovery of activity of the two clotting factors FVIII and FIX was satisfactory, above 80%. On a large scale, the active fraction in the clotting factor concentrate was successfully separated from the non-active fraction with either size exclusion (SE) material. In the preparation under investigation, the clotting factor VIII is found in a complex with the von Willebrand factor (vWF). The FVIII-vWF complex has a molecular mass of several millions. It dissociates in the presence of high concentrations of Ca2+ ions. Under such conditions FVIII and vWF were successfully separated with both SEC columns.

FLASHFLOOD: a 3D field-based similarity search and alignment method for flexible molecules

A three-dimensional field-based similarity search and alignment method for flexible molecules is introduced. The conformational space of a flexible molecule is represented in terms of fragments and torsional angles of allowed conformations. A user-definable property field is used to compute features of fragment pairs. Features are generalizations of CoMMA descriptors that characterize local regions of the property field by its local moments. The features are invariant under coordinate system transformations. Features taken from a query molecule are used to form alignments with fragment pairs in the database. An assembly algorithm is then used to merge the fragment pairs into full structures, aligned to the query. Key to the method is the use of a context adaptive descriptor scaling procedure as the basis for similarity. This allows the user to tune the weights of the various feature components based on examples relevant to the particular context under investigation. The property fields may range from simple, phenomenological fields, to fields derived from quantum mechanical calculations. We apply the method to the dihydrofolate/methotrexate benchmark system, and show that when one injects relevant contextual information into the descriptor scaling procedure, better results are obtained more efficiently. We also show how the method works and include computer times for a query from a database that represents approximately 23 million conformers of seventeen flexible molecules.

Differences between BCL2-break positive and negative follicular lymphoma unraveled by whole-exome sequencing

Depending on disease stage follicular lymphoma (FL) lack the t(14;18) in ~15-~50% of cases. Nevertheless, most of these cases express BCL2. To elucidate mechanisms triggering BCL2 expression and promoting pathogenesis in t(14;18)-negative FL, exonic single-nucleotide variant (SNV) profiles of 28 t(14;18)-positive and 13 t(14;18)-negative FL were analyzed, followed by the integration of copy-number changes, copy-neutral LOH and published gene-expression data as well as the assessment of immunoglobulin N-glycosylation sites. Typical FL mutations also affected t(14;18)-negative FL. Curated gene set/pathway annotation of genes mutated in either t(14;18)-positive or t(14;18)-negative FL revealed a strong enrichment of same or similar gene sets but also a more prominent or exclusive enrichment of immune response and N-glycosylation signatures in t(14;18)-negative FL. Mutated genes showed high BCL2 association in both subgroups. Among the genes mutated in t(14;18)-negative FL 555 were affected by copy-number alterations and/or copy-neutral LOH and 96 were differently expressed between t(14;18)-positive and t(14;18)-negative FL (P<0.01). N-glycosylation sites were detected considerably less frequently in t(14;18)-negative FL. These results suggest a diverse portfolio of genetic alterations that may induce or regulate BCL2 expression or promote pathogenesis of t(14;18)-negative FL as well as a less specific but increased crosstalk with the microenvironment that may compensate for the lack of N-glycosylation.