Serum hepatitis B core-related antigen is more accurate than hepatitis B surface antigen to identify inactive carriers, regardless of hepatitis B virus genotype

OBJECTIVES

To investigate whether hepatitis B surface antigen (HBsAg) and hepatitis B core-related antigen (HBcrAg) levels are useful to identify inactive carriers among HBeAg-negative patients infected by different hepatitis B virus (HBV) genotypes.

METHODS

In all, 202 consecutive HBeAg-negative patients with chronic hepatitis B, 135 inactive carriers and 67 with HBV activity, were prospectively followed for 1 year.

RESULTS

In HBeAg-negative patients, HBsAg levels differed across the different genotypes (p <0.001). The highest levels were observed in genotypes F or H (4.2 ± 0.6 logIU/mL), followed by genotype E (3.4 ± 1.1 logIU/mL), genotype A (3.4 ± 0.8 logIU/mL), and the lowest in genotype D (2.7 ± 1.1 logIU/mL). Variations in HBsAg levels were similar in inactive carriers and patients with HBV activity. HBsAg <3 logIU/mL showed good performance for identifying genotype D inactive carriers: 76% of genotype D inactive carriers met this cut-off versus ≤31% for genotypes A, E, F or H. However, in patients with genotype A, HBsAg levels ≤3.7 logIU/mL better classified inactive carriers. The combination of a single measurement of HBcrAg ≤3 logU/mL plus HBV DNA ≤2000 IU/mL yielded a positive predictive value and diagnostic accuracy >85% in all HBV genotypes, except genotype H or F, with values of 62.5% and 72.7%, respectively, for the two parameters.

CONCLUSIONS

HBsAg levels varied across genotypes in HBeAg-negative patients. HBsAg levels <3 logIU/mL were only useful for identifying genotype D inactive carriers. A single HBcrAg measurement ≤3 logU/mL plus HBV DNA ≤2000 IU/mL was highly accurate for identifying inactive carriers, regardless of their HBV genotype.

Estrogen Receptor Folding Modulates cSrc Kinase SH2 Interaction via a Helical Binding Mode

The estrogen receptors (ERs) feature, next to their transcriptional role, important nongenomic signaling actions, with emerging clinical relevance. The Src Homology 2 (SH2) domain mediated interaction between cSrc kinase and ER plays a key role in this; however the molecular determinants of this interaction have not been elucidated. Here, we used phosphorylated ER peptide and semisynthetic protein constructs in a combined biochemical and structural study to, for the first time, provide a quantitative and structural characterization of the cSrc SH2-ER interaction. Fluorescence polarization experiments delineated the SH2 binding motif in the ER sequence. Chemical shift perturbation analysis by nuclear magnetic resonance (NMR) together with molecular dynamics (MD) simulations allowed us to put forward a 3D model of the ER-SH2 interaction. The structural basis of this protein-protein interaction has been compared with that of the high affinity SH2 binding sequence GpYEEI. The ER features a different binding mode from that of the "two-pronged plug two-hole socket" model in the so-called specificity determining region. This alternative binding mode is modulated via the folding of ER helix 12, a structural element directly C-terminal of the key phosphorylated tyrosine. The present findings provide novel molecular entries for understanding nongenomic ER signaling and targeting the corresponding disease states.

Molecular interference in antibody-antigen interaction studied with magnetic force immunoassay

Molecular interferences are an important challenge in biotechnologies based on antibody-antigen interactions, such as sandwich immunoassays. We report how a sandwich immunoassay with magnetic particles as label can be used to probe interference by surfactants. Surfactants are often used to improve the performance of immunoassays, however the surfactants can affect the involved proteins and the mechanism of action of surfactant molecules on the antibody-antigen system is mostly unknown. As an example, we investigated molecular interference by a nonionic surfactant (Pluronic F-127) in a cardiac troponin (cTn) sandwich immunoassay with two monoclonal antibodies. The influence of the surfactant below the critical micelle concentration (0.00-0.04%) on dissociation properties was quantified in a magnetic tweezers setup, where a force is applied to the molecules via magnetic particle labels. The force-dependent dissociation curves revealed the existence of two distinct cTn-dependent bond types, namely a weak bond attributable to non-specific binding of cTn, and a strong bond attributable to the specific binding of cTn. The dissociation rate constant of the strong bonds increased with the surfactant concentration by about a factor of two. Circular dichroism spectroscopy data showed that the nonionic surfactant influences the conformation of cTn while not noticeably affecting the two monoclonal antibodies. This suggests that the surfactant-induced increase of the dissociation rate of the specific sandwich-type cTn binding may be related to a conformational change of the antigen molecule. The described methodology is an effective tool to study the influence of surfactants and other interferences on assays based on protein interactions.

Subtype-specific modulation of estrogen receptor-coactivator interaction by phosphorylation

The estrogen receptor (ER) is the number one target for the treatment of endocrine responsive breast cancer and remains a highly attractive target for new drug development. Despite considerable efforts to understand the role of ER post-translational modifications (PTMs), the complexity of these modifications and their impact, at the molecular level, are poorly understood. Using a chemical biology approach, fundamentally rooted in an efficient protein semisynthesis of tyrosine phosphorylated ER constructs, the complex role of the ER tyrosine phosphorylation is addressed here for the first time on a molecular level. The semisynthetic approach allows for the site-specific introduction of PTMs as well as biophysical probes. A combination of biophysical techniques, including NMR, with molecular dynamics studies reveals the role of the phosphorylation of the clinically relevant tyrosine 537 (Y537) in ERα and the analogous tyrosine (Y488) in ERβ. Phosphorylation has important effects on the dynamics of the ER Helix 12, which is centrally involved in receptor activity regulation, and on its interplay with ligand and cofactor binding, but with differential regulatory effects of the analogous PTMs on the two ER subtypes. Combined, the results bring forward a novel molecular model of a phosphorylation-induced subtype specific ER modulatory mechanism, alternative to the widely accepted ligand-induced activation mechanism.

A natural-product switch for a dynamic protein interface

Small ligands are a powerful way to control the function of protein complexes via dynamic binding interfaces. The classic example is found in gene transcription where small ligands regulate nuclear receptor binding to coactivator proteins via the dynamic activation function 2 (AF2) interface. Current ligands target the ligand-binding pocket side of the AF2. Few ligands are known, which selectively target the coactivator side of the AF2, or which can be selectively switched from one side of the interface to the other. We use NMR spectroscopy and modeling to identify a natural product, which targets the retinoid X receptor (RXR) at both sides of the AF2. We then use chemical synthesis, cellular screening and X-ray co-crystallography to split this dual activity, leading to a potent and molecularly efficient RXR agonist, and a first-of-kind inhibitor selective for the RXR/coactivator interaction. Our findings justify future exploration of natural products at dynamic protein interfaces.

Molecular recognition of epothilones by microtubules and tubulin dimers revealed by biochemical and NMR approaches

The binding of epothilones to dimeric tubulin and to microtubules has been studied by means of biochemical and NMR techniques. We have determined the binding constants of epothilone A (EpoA) and B (EpoB) to dimeric tubulin, which are 4 orders of magnitude lower than those for microtubules, and we have elucidated the conformation and binding epitopes of EpoA and EpoB when bound to tubulin dimers and microtubules in solution. The determined conformation of epothilones when bound to dimeric tubulin is similar to that found by X-ray crystallographic techniques for the binding of EpoA to the Tubulin/RB3/TTL complex; it is markedly different from that reported for EpoA bound to zinc-induced sheets obtained by electron crystallography. Likewise, only the X-ray structure of EpoA bound to the Tubulin/RB3/TTL complex at the luminal site, but not the electron crystallography structure, is compatible with the results obtained by STD on the binding epitope of EpoA bound to dimeric tubulin, thus confirming that the allosteric change (structuring of the M-loop) is the biochemical mechanism of induction of tubulin assembly by epothilones. TR-NOESY signals of EpoA bound to microtubules have been obtained, supporting the interaction with a transient binding site with a fast exchange rate (pore site), consistent with the notion that epothilones access the luminal site through the pore site, as has also been observed for taxanes. Finally, the differences in the tubulin binding affinities of a series of epothilone analogues has been quantitatively explained using the newly determined binding pose and the COMBINE methodology.

Site-specific protection and dual labeling of human epidermal growth factor (hEGF) for targeting, imaging, and cargo delivery

Well-defined human epidermal growth factor (hEGF) constructs featuring selectively addressable labels are urgently needed to address outstanding questions regarding hEGF biology. A protein-engineering approach was developed to provide access to hEGF constructs that carry two cysteine-based site-specific orthogonal labeling sites in multi-milligram quantities. Also, a site-selective (de)protection and labeling approach was devised, which allows selective modification of these hEGF constructs. The hEGF, featuring three native disulfide bonds, was expressed featuring additional sulfhydryl groups, in the form of cysteine residues, as orthogonal ligation sites at both the N and C termini. Temporary protection of the N-terminal cysteine unit, in the form of a thiazolidine ring, avoids interference with protein folding and enables sequential labeling in conjunction with the cysteine residue at the C terminus. Based on thus-generated hEGF constructs, sequential and site-specific labeling with a variety of molecular probes could be demonstrated, thus leading to a biological fully functional hEGF with specifically incorporated fluorophores or protein cargo and native cellular targeting and uptake profiles. Thus, this novel strategy provides a robust entry to high-yielding access of hEGF and rapid and easy site-specific and multifunctional dual labeling of this growth factor.

Clostridium difficile in the ICU: study of the incidence, recurrence, clinical characteristics and complications in a university hospital

OBJECTIVE

Although several studies have established the association between antibiotics and Clostridium difficile infection (CDI), there is a lack of epidemiological studies on the incidence of CDI in European Intensive Care Units outside the context of infection outbreaks. The present study describes the incidence, patient characteristics, complications, and recurrence rates of CDI in a Spanish ICU.

DESIGN

A retrospective study was carried out.

SETTING

A clinical-surgical ICU with 34 beds, a tertiary referral hospital with 1400 beds.

PATIENTS

All patients over 18 years of age admitted to the ICU from January 2010 to December 2011 with diarrhea for more than 48 h.

INTERVENTIONS

None.

STUDY VARIABLES

Underlying diseases, risk factors, fever, leukocyte count, complications, recurrence of infection.

RESULTS

A total of 1936 adult patients were admitted. Seven patients acquired CDI (0.36%), representing an infection rate of 3.1 per 10,000 bed-days and a cumulative incidence rate of 3.6 in two years. The mean age was 61 years. Six patients showed some degree of immunosuppression. The mean APACHE II score at ICU admission was 17 (IQR 13-24). Severe sepsis was reported in 5 cases of CDI, three of which presented shock and multiorgan dysfunction. Four patients presented recurrence of CDI during hospitalization. ICU admission was prolonged for a mean of 24 days (SD 17.8) after diagnosis.

CONCLUSIONS

Less than 1% of the patients admitted to a clinical-surgical ICU in a large teaching institution in Spain developed CDI. However, a high risk of recurrence/complications was associated with prolonged ICU stay.

Proline primed helix length as a modulator of the nuclear receptor-coactivator interaction

Nuclear receptor binding to coactivator proteins is an obligate first step in the regulation of gene transcription. Nuclear receptors preferentially bind to an LXXLL peptide motif which is highly conserved throughout the 300 or so natural coactivator proteins. This knowledge has shaped current understanding of this fundamental protein-protein interaction, and continues to inspire the search for new drug therapies. However, sequence specificity beyond the LXXLL motif and the molecular functioning of flanking residues still requires urgent addressing. Here, ribosome display has been used to reassess the estrogen receptor for new and enlarged peptide recognition motifs, leading to the discovery of a potent and highly evolved PXLXXLLXXP binding consensus. Molecular modeling and X-ray crystallography studies have provided the molecular insights on the role of the flanking prolines in priming the length of the α-helix and enabling optimal interactions of the α-helix dipole and its surrounding amino acids with the surface charge clamp and the receptor activation function 2. These findings represent new structural parameters for modulating the nuclear receptor-coactivator interaction based on linear sequences of proteinogenic amino acids and for the design of chemically modified inhibitors.

Risk in dosing regimens for 25-OH vitamin D supplementation in chronic haemodialysis patients

INTRODUCTION

25-OH vitamin D (25-OHvitD) insufficiency or deficiency should be treated in haemodialysis (HD) patients, although the 25-OHvitD target, drug or dosing regimens are unclear.

AIMS

To describe factors associated with 25-OHvitD levels in HD patients and to assess the effect of three dosing regimens to supplement 25-OHvitD (calcifediol) on serum calcium (Ca), phosphate (P), parathyroid hormone (PTH), 25-OHvitD and 1,25-OHvitD.

METHODS

Two hundred and seventeen patients from three HD units were studied. Demographic and biochemical data were collected at baseline. Two different 25-OHvitD assays were used. One hundred and sixty-seven patients were treated with various calcifediol dosing regimens. The same biochemical determinations were repeated after 3 months of treatment.

RESULTS

At baseline, 12.9% of patients had 25-OHvitD <10 ng/ml. In multivariate linear regression, the season (lower in winter) and the assay method were determinants of 25-OHvitD concentration. Following calcifediol supplementation, 25-OHvitD, calcium and phosphate increased, while PTH diminished with statistical significance. After treatment, there were positive correlations between 25-OHvitD and Ca (r = 0.28, p < 0.0001) or 1,25-OHvitD (r = 0.75, p < 0.0001) that were not observed in the baseline dataset. High concentrations of post-treatment 25-OHvitD were associated with higher 1,25-OHvitD levels. Calcemia increased more in those treated with concomitant active vitamin D or those having suppressed baseline PTH, while PTH decreased more in those having above-target PTH levels.

CONCLUSIONS

Standardisation of methods to determine 25-OHvitD blood levels is needed. In HD patients, calcifediol increased 25-OHvitD, calcemia and phosphatemia and lowered PTH. Caution should be exercised with the higher calcifediol dosing regimens, especially in patients with suppressed PTH or on vitamin D receptor activators.

ATR controls cellular adaptation to hypoxia through positive regulation of hypoxia-inducible factor 1 (HIF-1) expression

Tumor cells adaptation to severe oxygen deprivation (hypoxia) plays a major role in tumor progression. The transcription factor HIF-1 (hypoxia-inducible factor 1), whose α-subunit is stabilized under hypoxic conditions is a key component of this process. Recent studies showed that two members of the phosphoinositide 3-kinase-related kinases (PIKKs) family, ATM (ataxia telangiectasia mutated) and DNA-PK (DNA-dependent protein kinase), regulate the hypoxic-dependent accumulation of HIF-1. These proteins initiate cellular stress responses when DNA damage occurs. In addition, it has been demonstrated that extreme hypoxia induces a replicative stress resulting in regions of single-stranded DNA at stalled replication forks and the activation of ATR (ataxia telangiectasia and Rad3 related protein), another member of the PIKKs family. Here, we show that even less severe hypoxia (0.1% O2) also induces activation of ATR through replicative stress. Importantly, in using either transiently silenced ATR cells, cells expressing an inactive form of ATR or cells exposed to an ATR inhibitor (CGK733), we demonstrate that hypoxic ATR activation positively regulates the key transcription factor HIF-1 independently of the checkpoint kinase Chk1. We show that ATR kinase activity regulates HIF-1α at the translational level and we find that the elements necessary for the regulation of HIF-1α translation are located within the coding region of HIF-1α mRNA. Finally, by using three independent cellular models, we clearly show that the loss of ATR expression and/or kinase activity results in the decrease of HIF-1 DNA binding under hypoxia and consequently affects protein expression levels of two HIF-1 target genes, GLUT-1 and CAIX. Taken together, our data show a new function for ATR in cellular adaptation to hypoxia through regulation of HIF-1α translation. Our work offers new prospect for cancer therapy using ATR inhibitors with the potential to decrease cellular adaptation in hypoxic tumors.

The NMR structure of human obestatin in membrane-like environments: insights into the structure-bioactivity relationship of obestatin

The quest for therapeutic applications of obestatin involves, as a first step, the determination of its 3D solution structure and the relationship between this structure and the biological activity of obestatin. On this basis, we have employed a combination of circular dichroism (CD), nuclear magnetic resonance (NMR) spectroscopy, and modeling techniques to determine the solution structure of human obestatin (1). Other analogues, including human non-amidated obestatin (2) and the fragment peptides (6–23)-obestatin (3), (11–23)-obestatin (4), and (16–23)-obestatin (5) have also been scrutinized. These studies have been performed in a micellar environment to mimic the cell membrane (sodium dodecyl sulfate, SDS). Furthermore, structural-activity relationship studies have been performed by assessing the in vitro proliferative capabilities of these peptides in the human retinal pigmented epithelial cell line ARPE-19 (ERK1/2 and Akt phosphorylation, Ki67 expression, and cellular proliferation). Our findings emphasize the importance of both the primary structure (composition and size) and particular segments of the obestatin molecule that posses significant α-helical characteristics. Additionally, details of a species-specific role for obestatin have also been hypothesized by comparing human and mouse obestatins (1 and 6, respectively) at both the structural and bioactivity levels.

Structural characterization of the lignin in the cortex and pith of elephant grass (Pennisetum purpureum) stems

The structure of the lignin in the cortex and pith of elephant grass (Pennisetum purpureum) stems was studied both in situ and in isolated milled "wood" lignins by several analytical methods. The presence of p-coumarate and ferulate in the cortex and pith, as well as in their isolated lignins, was revealed by pyrolysis in the presence of tetramethylammonium hydroxide, and by 2D NMR, and indicated that ferulate acylates the carbohydrates while p-coumarate acylates the lignin polymer. 2D NMR showed a predominance of alkyl aryl ether (β-O-4') linkages (82% of total interunit linkages), with low amounts of "condensed" substructures, such as resinols (β-β'), phenylcoumarans (β-5'), and spirodienones (β-1'). Moreover, the NMR also indicated that these lignins are extensively acylated at the γ-carbon of the side chain. DFRC analyses confirmed that p-coumarate groups acylate the γ-OHs of these lignins, and predominantly on syringyl units.

Structural characterization of guaiacyl-rich lignins in flax (Linum usitatissimum) fibers and shives

The structural characteristics of the lignins from flax (Linum usitatissimum) fibers and shives were studied. Significant differences in the content and composition of the lignin from both parts were observed. The lignin contents were 3.8% in the fibers and 29.0% in the shives. Analysis by Py-GC/MS indicated a H:G:S molar ratio of 13:72:15 in the milled wood lignin (MWL) isolated from flax fibers and a molar ratio of 5:87:8 in the MWL isolated from flax shives. In addition, 2D-NMR showed a predominance of β-O-4' aryl ether linkages, followed by β-5' phenylcoumaran and β-β' resinol-type linkages in both MWLs, with a higher content of condensed linkages in flax shives. Thioacidolysis (followed by Raney nickel desulfurization) gave further information on the lignin units involved in the different linkages and confirmed the enrichment of G units. The thioacidolysis dimers released were similar from both lignins, with a predominance of the β-5' followed by β-1' and 5-5' structures.

Conformational selection of the AGA*IA(M) heparin pentasaccharide when bound to the fibroblast growth factor receptor

The interaction of the synthetic pentasaccharide AGA*IA(M) (GlcNS,6S-GlcA-GlcNS,3S,6S-IdoA2S-GlcNS,6S-Me) with the extracellular Ig2 domain of the fibroblast growth factor receptor (FGFR2) has been studied by NMR and computational methods. Analysis of the heparin pentasaccharide in the free state and in the complex indicates the existence of a conformational selection process. Although an equilibrium exists between the (1)C(4) and (2)S(0) conformers (ratio 60:40) of the 2-O-sulfo-α-L-iduronate ring (IdoA2S) in the free state, FGFR2 selects only the unique twisted-boat (2)S(0) conformation of this IdoA2S residue. In addition, the protein residues involved in the binding with AGA*IA(M) have also been characterized. The NMR results obtained, from both the ligand and protein perspective, were employed to model the bound conformation of the pentasaccharide by a combined docking and molecular dynamic simulation approach.

Insights into the interaction of discodermolide and docetaxel with tubulin. Mapping the binding sites of microtubule-stabilizing agents by using an integrated NMR and computational approach

The binding interactions of two antitumor agents that target the paclitaxel site, docetaxel and discodermolide, to unassembled α/β-tubulin heterodimers and microtubules have been studied using biochemical and NMR techniques. The use of discodermolide as a water-soluble paclitaxel biomimetic and extensive NMR experiments allowed the detection of binding of microtubule-stabilizing agents to unassembled tubulin α/β-heterodimers. The bioactive 3D structures of docetaxel and discodermolide bound to α/β-heterodimers were elucidated and compared to those bound to microtubules, where subtle changes in the conformations of docetaxel in its different bound states were evident. Moreover, the combination of experimental TR-NOE and STD NMR data with CORCEMA-ST calculations indicate that docetaxel and discodermolide target an additional binding site at the pore of the microtubules, which is different from the internal binding site at the lumen previously determined by electron crystallography. Binding to this pore site can then be considered as the first ligand-protein recognition event that takes place in advance of the drug internalization process and interaction with the lumen of the microtubules.

Lignin composition and structure in young versus adult Eucalyptus globulus plants

Lignin changes during plant growth were investigated in a selected Eucalyptus globulus clone. The lignin composition and structure were studied in situ by a new procedure enabling the acquisition of two-dimensional nuclear magnetic resonance (2D-NMR) spectra on wood gels formed in the NMR tube as well as by analytical pyrolysis-gas chromatography-mass spectrometry. In addition, milled-wood lignins were isolated and analyzed by 2D-NMR, pyrolysis-gas chromatography-mass spectrometry, and thioacidolysis. The data indicated that p-hydroxyphenyl and guaiacyl units are deposited at the earlier stages, whereas the woods are enriched in syringyl (S) lignin during late lignification. Wood 2D-NMR showed that β-O-4' and resinol linkages were predominant in the eucalypt lignin, whereas other substructures were present in much lower amounts. Interestingly, open β-1' structures could be detected in the isolated lignins. Phenylcoumarans and cinnamyl end groups were depleted with age, spirodienone abundance increased, and the main substructures (β-O-4' and resinols) were scarcely modified. Thioacidolysis revealed a higher predominance of S units in the ether-linked lignin than in the total lignin and, in agreement with NMR, also indicated that resinols are the most important nonether linkages. Dimer analysis showed that most of the resinol-type structures comprised two S units (syringaresinol), the crossed guaiacyl-S resinol appearing as a minor substructure and pinoresinol being totally absent. Changes in hemicelluloses were also shown by the 2D-NMR spectra of the wood gels without polysaccharide isolation. These include decreases of methyl galacturonosyl, arabinosyl, and galactosyl (anomeric) signals, assigned to pectin and related neutral polysaccharides, and increases of xylosyl (which are approximately 50% acetylated) and 4-O-methylglucuronosyl signals.

Synthesis and antiprotozoal activity of N-alkoxy analogues of the trypanocidal lead compound 4,4'-bis(imidazolinylamino)diphenylamine with improved human blood-brain barrier permeability

To improve the blood-brain barrier permeability of the trypanocidal lead compound 4,4'-bis(imidazolinylamino)diphenylamine (1), five N-alkoxy analogues were synthesized from bis(4-isothiocyanatophenyl)amine and N-alkoxy-N-(2-aminoethyl)-2-nitrobenzenesulfonamides following successive chemical reactions in just one reactor ("one-pot procedure"). This involved: (a) formation of a thiourea intermediate, (b) removal of the amine protecting groups, and (c) intramolecular cyclization. The blood-brain barrier permeability of the compounds determined in vitro by transport assays through the hCMEC/D3 human cell line, a well-known and characterized human cellular blood-brain barrier model, showed that the N-hydroxy analogue 16 had enhanced blood-brain barrier permeability compared with the unsubstituted lead compound. Moreover, this compound displayed low micromolar IC(50) against Trypanosoma brucei rhodesiense and Plasmodium falciparum and moderate activity by intraperitoneal administration in the STIB900 murine model of acute sleeping sickness.

Polymerization of lignosulfonates by the laccase-HBT (1-hydroxybenzotriazole) system improves dispersibility

The ability of laccases from Trametes villosa (TvL), Myceliophthora thermophila (MtL), Trametes hirsuta (ThL) and Bacillus subtilis (BsL) to improve the dispersion properties of calcium lignosulfonates 398 in the presence of HBT as a mediator was investigated. Size exclusion chromatography showed an extensive increase in molecular weight of the samples incubated with TvL and ThL by 107% and 572% from 28400 Da after 17h of incubation, respectively. Interestingly, FTIR spectroscopy, (13)C NMR and Py-GC/MS analysis of the treated samples suggested no substantial changes in the aromatic signal of the lignosulfonates, a good indication of the ability of TvL/ThL-HBT systems to limit their effect on functional groups without degrading the lignin backbone. Further, the enzymatic treatments led to a general increase in the dispersion properties, indeed a welcome development for its application in polymer blends.

Psychological impact of Crohn's disease on patients in remission: anxiety and depression risks

BACKGROUND

the role of anxiety and depression in CD patients in remission has been poorly investigated.

OBJECTIVE

the aim of the study was to evaluate the frequency of anxiety and depression symptoms in CD patients in remission, and potential factors influencing the development of these symptoms.

METHODS

CD patients older than 18 years in remission for at least 6 months before study entry were included. CD remission was defined as a Crohn s Disease Activity Index (CDAI) < 150 points together with C-reactive protein < 5 mg/L. A demographic questionnaire was filled in, and all patients were clinically classified. The therapy maintaining remission was also recorded. A Hospital Anxiety and Depression scale (HAD) was administered to all patients. Results are shown as OR and 95% CI, and analyzed by logistic regression.

RESULTS

92 consecutive patients were included (48 male, mean age 37 years, range from 18 to 71 years). One patient failed to correctly fill in the questionnaire. Anxiety and depression symptoms were present in 36 (39%) and 22 (24%) patients, respectively. Infliximab therapy was the only factor associated with anxiety (OR = 3.11; 95% CI: 1.03-9.43; p < 0.05). In contrast, the presence of depressive symptoms is less frequent in patients under infliximab therapy (OR = 0.16; 95% CI: 0.02-0.97; p < 0.05).

CONCLUSIONS

despite clinical remission, an important number of CD patients present with anxiety or depressive symptoms. Infliximab therapy in CD patients is associated to more anxiety but fewer depressive symptoms. CD patients in remission would probably benefit from psychological support.

Solution structures of chemoenzymatically synthesized heparin and its precursors

We report the first chemoenzymatic synthesis of the stable isotope-enriched heparin from a uniformly labeled [(13)C,(15)N]N-acetylheparosan (-GlcA(1,4)GlcNAc-) prepared from E. coli K5. Glycosaminoglycan (GAG) precursors and heparin were formed from N-acetylheparosan by the following steps: chemical N-deacetylation and N-sulfonation leading to N-sulfoheparosan (-GlcA(1,4)GlcNS-); enzyme-catalyzed C5-epimerization and 2-O-sulfonation leading to undersulfated heparin (-IdoA2S(1,4)GlcNS-); enzymatic 6-O-sulfonation leading to the heparin backbone (-IdoA2S(1,4)GlcNS6S-); and selective enzymatic 3-O-sulfonation leading to the anticoagulant heparin, containing the GlcNS6S3S residue. Heteronuclear, multidimensional nuclear magnetic resonance spectroscopy was employed to analyze the chemical composition and solution structure of [(13)C,(15)N]N-acetylheparosan, precursors, and heparin. Isotopic enrichment was found to provide well-resolved (13)C spectra with the high sensitivity required for conformational studies of these biomolecules. Stable isotope-labeled heparin was indistinguishable from heparin derived from animal tissues and is a novel reagent for studying the interaction of heparin with proteins.

Airway inflammation and cough sensitivity in cough-variant asthma

BACKGROUND

Mechanisms underlying cough and bronchoconstriction in patients with cough-variant asthma (CVA) are not well established. Differences in location or degree of activation of eosinophils and allergic cytokines have been suggested as the likely causes. To address this issue, we have carried out a comparative study of airway inflammatory markers between patients with CVA and classic asthma (CA). The relationship between these markers with airway hyperresponsiveness (AHR) and cough sensitivity has also been studied.

METHODS

Twenty-seven non-smokers and steroid-naive patients with CVA (12) and CA (15) were examined. Capsaicin challenge, histamine bronchoprovocation test, nitric oxide levels in exhaled air and sputum induction were performed in all of them. Differential cell sputum recount and supernatant concentrations of eosinophil granule-derived cationic proteins (ECP), interleukin (IL)5, IL8 and tumour necrosis factor (TNF)-alpha were also measured.

RESULTS

There were no significant differences in either the inflammatory pattern of soluble markers or differential cell counts between CA and CVA. Histamine PC20 was correlated with IL-5 in CVA, whereas it was associated with sputum eosinophilia in CA. Cough sensitivity (log C5) and histamine PC20 were inversely related in CA.

CONCLUSIONS

Although the pattern of inflammatory sputum markers in patients with asthma and cough-variant asthma is similar, its relation with bronchial hyperreactivity and cough sensitivity is different in each group.

Cough reflex testing with inhaled capsaicin in the study of chronic cough

OBJECTIVES

To assess the utility of capsaicin test in the differential diagnosis of non-productive causes of chronic cough and to examine the effects of treatment on this reflex.

PARTICIPANTS

86 healthy volunteers and 101 patients with chronic cough: asthma (n: 54) gastroesophageal reflux (n: 35) and post-nasal drip syndrome (n: 12).

DESIGN

Prospective intervention trial. Spirometry, bronchoprovocation test with histamine (PC20), and cough challenge with ascending concentrations of capsaicin (0.49-500 microM) were initially performed in all subjects. Patients were treated for 3 months according to the origin of the cough. Concentrations that elicited two (C2) and five or more coughs (C5) were determined before and after treatment.

RESULTS

In healthy subjects, cough sensitivity to capsaicin was not influenced by gender or smoking status; however, women with chronic cough were more sensitive to cough challenge than men. C2 and C5 were significantly lower in patients with asthma or gastroesophageal reflux than in post-nasal drip syndrome. No significant correlation was observed between the capsaicin cough threshold and PC20. Cough sensitivity did not improve significantly in most patients with asthma or gastroesophageal reflux despite adequate medical treatment during 3 months. Discriminative value of capsaicin test to differentiate healthy subjects from patients with asthma or reflux was poor.

CONCLUSIONS

Cough sensitivity to inhaled capsaicin is a safe and reproducible tool in the study of chronic cough. However, its usefulness for the management and differential diagnosis is limited.

Beneficial effect of vegetable protein diet supplemented with psyllium plantago in patients with hepatic encephalopathy and diabetes mellitus

A controlled crossover study was performed in 8 diabetic patients with chronic portal-systemic encephalopathy. After a basal period the patients were treated during periods A and B. During period A, a meat protein diet (0.8 g/kg body wt, approximately 1800 kcal/day) was consumed and neomycin plus laxatives were given. During period B patients received vegetable protein (0.8 g/kg body wt, 1800 kcal/day). This diet was supplemented with psyllium fiber to reach 35 g of fiber per day. Four patients were randomly assigned to receive the treatments in the order A-B and the other 4 patients in the order B-A. At the end of the first experimental period, fasting glucose levels were 204 +/- 86 mg% in the meat protein diet group and 127 +/- 8 mg% in the vegetable protein diet group (p less than 0.014). The patients were receiving 2.5 +/- 0.2 g/day and 2.1 +/- 0.5 g/day of tolbutamide at the end of the meat protein diet and vegetable protein diet, respectively. In all cases, fasting glucose levels decreased at the end of the vegetable diet period regardless of the previous treatment. An improvement of greater than or equal to 25 mg% of fasting glucose levels was observed in 7 of the 8 patients after the vegetable protein diet and in no case after the meat protein diet (p less than 0.0078). The parameters of encephalopathy were comparable at the end of both the meat protein diet and the vegetable protein diet. A significant increase in the number of bowel movements was noticed after the vegetable diet plus fiber (p less than 0.01). We propose the use of vegetable diet plus fiber to facilitate the treatment of patients with both diabetes and hepatic encephalopathy.

Suprahypophyseal dysfunction in a patient with asexual ateleiosis

The neuroendocrine function of a 19 years old female dwarf with primary amenorrhoea and lack of sexual development (asexual ateleiosis) was studied. Undetectable fasting plasma levels of growth hormone (GH) and a lack of response to three different provocative stimuli was observed. Oestrogen administratin did not modify the GH response. Thyroid and adrenal function were within normal limits. Undetectable plasma levels of immunoreactive oestradiol and lack of oestrogenic activity in vaginal smears indicated absence of ovarian function. Low levels of circulating gonadotrophins with a significant rise after synthetic LH-RH administration was demonstrated, while clomiphene citrate failed to induce ovulation. Following 6 months of continuous GH administration a significant increase in the growth rate was evident, whereas no pubertal development was observed. These data are interpreted as demonstrating the suprahypophyseal origin of the sexual infantilism in a patient with inappropriate GH secretion. It is suggested that a combined deficiency of LH-RH and GH-RH may account for the aetiology of this disorder.

[Percutaneous splenoportogammagraphy in the study of patients with portal hypertension]

Percutaneous esplenoportogammagraphy in 28 patients with portal hypertension, was carried out; in three patients studies were done before and after a derivative operation; in nine only after operation for portal hypertension and thirteen patients were not surgically treated. Hepatic maximal opacification was obtained in 4.35 seconds. In the operated patients the tecnesium reached right cardiac chambers in 2.91 seconds. In three of the thirteen patients with the test, there were intrahepatic circulatory pattern changes, average spleen-liver was 6 seconds and spleen-heart, 7 seconds, that is, esplenoportal perfussion was poor. In all the operated patients the decreased circulation time spleen-heart and the typical image showed anastomosis permeability.