Anastrozole as neoadjuvant therapy for patients with hormone-dependent, locally-advanced breast cancer

BACKGROUND

We investigated the efficacy and safety of anastrozole as neoadjuvant therapy in a group of postmenopausal patients with locally-advanced breast cancer.

PATIENTS AND METHODS

This was an open-label trial, which recruited patients with histopathologically-confirmed unilateral, locally-advanced, estrogen-receptor-positive breast cancer (stage IIIA/B). All patients received anastrozole 1 mg/day for 3 months, after which the clinical response was evaluated. All patients with a complete or partial clinical response (cCR or cPR) underwent surgery (radical modified mastectomy), after which patients continued with the same therapy for two years or until progression. Primary end points were clinical response rate (cCR + cPR), surgery rate, pathological complete response rate and tolerability profile.

RESULTS

cCR and cPR were seen in 61/112 (54.5%) and 32/112 (28.6%) patients (n=112), respectively, giving an objective response rate of 93/112 (83%) patients. Following surgery in responding patients, 14/61 patients (23%) had a pathological CR and 47/61 (77%) patients had a pathological PR.

CONCLUSION

Neoadjuvant anastrozole treatment was highly effective and well-tolerated in postmenopausal women with hormone-dependent locally-advanced breast cancer.

Pulmonary involvement in tuberous sclerosis

Tuberous sclerosis is a neurocutaneous syndrome involving many tissues. Pulmonary involvement is rare. Pulmonary cases are usually women of child-bearing age who present with spontaneous pneumothorax or progressive dyspnea. In childhood and, even more, in male patients, pulmonary involvement by tuberous sclerosis is exceptional. We report on a 4-year-old male patient diagnosed in the first months of life with tuberous sclerosis with predominantly respiratory symptoms (frequently with acute RDS criteria), in whom lung involvement was pathologically confirmed.

The importance of clinical factors in parenteral nutrition-associated hypertriglyceridemia

AIMS

The purpose of this study was to establish the relevance of several clinical factors associated with parenteral nutrition (PN) hypertriglyceridemia and to construct a predictive model for this complication.

METHOD

This multicenter study included all patients with initial serum triglyceridemia <3 mmol and receiving a minimum of 7 days' PN therapy. The study ended for each patient when hypertriglyceridemia developed or PN was terminated. Two multivariate models were constructed, one to study the clinical factors and the second to predict plasma triglyceridemia. A total of 22 clinical factors studied as independent variables were included in the multiple-step regression models only when they showed a P-value over 0.1. Statistical significance was determined by the confidence interval of the odds ratio (OR) and the partial regression coefficient (b).

RESULTS

The study included 260 patients from 14 hospitals. Lipid administration was 0.83+/-0.37 g/kg/day. Among the total, 68 patients (26.2%) showed hypertriglyceridemia. Variables included in both models were serum glucose (OR, 2.63; b, 0.06), renal failure (OR, 10.56; b, 1.70), corticoid administration >0.5 mg/kg (OR, 7.98; b, 0.97), pancreatitis (OR, 4.38; b, 0.64), sepsis (OR, 4.48; b, 0.24), lipids infused (OR, 3.03; b, 0.24) and heparin administration >3 mg/kg/day (OR, 0.11; b, -1.21).

CONCLUSION

Although the rate of lipid infusion was low, certain clinical factors modified triglyceridemia. Nevertheless, relatively fast plasma clearance of lipids infused indicates that a reduction in lipid supply could be a quick, effective measure for controlling hypertriglyceridemia. Thus, careful monitoring of patients with clinical factors predicting risk in the model studied, with adjustment of lipid perfusion rates accordingly, is suggested to avoid hypertriglyceridemia.

Randomised controlled trial of montelukast plus inhaled budesonide versus double dose inhaled budesonide in adult patients with asthma

BACKGROUND

Inhaled corticosteroids (ICS) affect many inflammatory pathways in asthma but have little impact on cysteinyl leukotrienes. This may partly explain persistent airway inflammation during chronic ICS treatment and failure to achieve adequate asthma control in some patients. This double blind, randomised, parallel group, non-inferiority, multicentre 16 week study compared the clinical benefits of adding montelukast to budesonide with doubling the budesonide dose in adults with asthma.

METHODS

After a 1 month single blind run in period, patients inadequately controlled on inhaled budesonide (800 microg/day) were randomised to receive montelukast 10 mg + inhaled budesonide 800 microg/day (n=448) or budesonide 1600 microg/day (n=441) for 12 weeks.

RESULTS

Both groups showed progressive improvement in several measures of asthma control compared with baseline. Mean morning peak expiratory flow (AM PEF) improved similarly in the last 10 weeks of treatment compared with baseline in both the montelukast + budesonide group and in the double dose budesonide group (33.5 v 30.1 l/min). During days 1-3 after start of treatment, the change in AM PEF from baseline was significantly greater in the montelukast + budesonide group than in the double dose budesonide group (20.1 v 9.6 l/min, p<0.001), indicating faster onset of action in the montelukast group. Both groups showed similar improvements with respect to "as needed" beta agonist use, mean daytime symptom score, nocturnal awakenings, exacerbations, asthma free days, peripheral eosinophil counts, and asthma specific quality of life. Both montelukast + budesonide and double dose budesonide were generally well tolerated.

CONCLUSION

The addition of montelukast to inhaled budesonide is an effective and well tolerated alternative to doubling the dose of inhaled budesonide in adult asthma patients experiencing symptoms and inadequate control on budesonide alone.

[Neurofibromatosis type 2 as a result of a de novo mutation: a case report]

INTRODUCTION

Neurofibromatosis type 2 is a dominant autosomic hereditary disease which courses with distinct tumours of the central nervous system and scant cutaneous manifestations. The increased knowledge of the natural history and the genetics of NF 2 acquired over the past few years has shown that clinical onset possibly occurs during the paediatric age and an early diagnosis of these patients can be decisive in the final outcome.

CLINICAL CASE

A 12 year old girl who visited the clinic because of a month old presentation of cervical tumour, otalgia and dysphonia. Exploration revealed signs of cranial nerve disorder and the magnetic resonance (MR) showed bilateral schwannomas of the eighth cranial nerves. The extension study showed ocular, auditory, troncoencephalic and cervical spinal cord disorders. The patient died three months after hospital admission. The genetic study showed a de novo mutation in the NF 2 gene (chromosome 22q12).

DISCUSSION

The identification of the various mutations that cause NF 2 has enabled the early diagnosis of the patient s relatives. However, there are still patients who have not been confirmed genetically. Furthermore, de novo mutations are not predictable. NF 2 diagnosis is still clinical. In the last few years, two disease phenotypes have been defined: mild and moderate/serious, which is associated with an early onset and de novo mutations. The high incidence rate of cataracts and other associated tumours, such as those affecting paraspinal and cutaneous areas together with meningiomas, which up until now could have gone unnoticed, has also been observed. Clinical onset in the paediatric age is more frequent than was expected and shows distinct and subtle symptoms.

Prevention of non-steroidal antiinflammatory drugs-induced gastropathy: follow up of protocol adherence

OBJECTIVE

To reach a consensus on and evaluate the compliance of the protocol for the prophylaxis of gastropathy induced by non-steroidal anti-inflammatory drugs with 20 mg omeprazole per day.

PATIENTS AND METHOD

Three transversal studies have been carried out on patients admitted to our hospital before establishing the protocol, immediately after and 6 months later.

RESULTS

Between 16 and 24% of patients admitted to our hospital take non-steroidal anti-inflammatory drugs. Before the application of the protocol 34.7% of prescriptions coincided with this use. After its establishment adherence by the prescribing doctors improved to 51.8% (c2 = 5.27, p = 0.02) and at 6 months it reached 51.4% adherence, an improvement that continued being significative (c2 = 5.74, p = 0.01). The main reason for non-compliance was the use of ranitidine instead of omeprazole. One of the most useful methods for improving adhesion has been meeting with the medical services that most use the anti-inflammatory drugs, focussing specifically on the use of the protocol.

CONCLUSIONS

The follow-up of the protocol shows an improvement in compliance after the establishment stage which is maintained after 6 months. Adherence by the prescribing doctors to the treatment, nevertheless, is lower than had been hoped.

Isolation and characterization of four isomers of a C(60) bisadduct with a TTF derivative. Study of their radical ions

A family of triads composed of C(60) attached by a rigid spacer to two identical TTF moieties has been synthesized, and some of the isomers have been isolated and characterized by UV-vis spectroscopy, LDI-TOF-MS, and HMBC NMR spectroscopy. AM1 semiempirical calculations of the dipolar moments and the heats of formation of the different isomers have been carried out in order to verify their assignments. Oxidation and reduction of the triads affords the derived radical ion systems, TTF(+*)-C(60)-TTF(+*) and TTF-C(60)(-*)-TTF, which were studied by EPR spectroscopy. Spin density distributions of these radical cations and radical anions show that the unpaired electron is located mainly on the TTF and fullerene moieties, respectively. However, while the EPR signals obtained from the radical cations are very similar for all the isomers, the structured signals observed for the radical anions arising from the coupling of the unpaired electron with the hydrogen atoms of the methylene bridges in the spacer show that there is a strong influence of the isomerism on the spin distribution. Importantly, the theoretical calculations of the spin density distributions of the radical anions fit well with the experimental EPR results.

An analytical solution to the problem of the orientation of rigid particles by planar obstacles. Application to membrane systems and to the calculation of dipolar couplings in protein NMR spectroscopy

Nonspherical particles or molecules experience an ordering effect in the presence of obstacles due to the restrictions they place on the orientation of those molecules that are in their proximity. Obstacles may be the limits of a membrane in which the molecule is embedded, oriented mesoscopic systems such as bicelles, or membrane fragments used to induce weak protein alignment in a magnetic field. The overall shape of most proteins can be described to a good approximation by an ellipsoidal particle. Here we describe and solve analytically the problem of the orientation of ellipsoidal particles by planar obstacles. Simple expressions are derived for the orientational distribution function and the order parameter. These expressions allow the analytical calculation of the residual dipolar couplings for a protein of known three-dimensional structure oriented by steric effects. The results are in good agreement with experiment and with the results of previously described simulations. However, they are obtained analytically in a fraction of the time and therefore open the possibility to include the optimization of the overall shape in the determination of three-dimensional structures using residual dipolar coupling constraints. The equations derived are general and can also be applied to problems of a completely different nature. In particular, previous equations describing the orientation of particles embedded in membranes are verified and generalized here.

Use of the Pediatric Risk of Mortality Score as predictor of death and serious neurologic damage in children after submersion

OBJECTIVE

To evaluate the Pediatric Risk of Mortality score (PRISM score) as a tool to evaluate the vital and neurologic prognosis of patients after submersion.

METHODS

We conducted a retrospective analysis of the clinical histories of patients admitted to a tertiary pediatric hospital, Hospital Sant Joan de Déu, Barcelona, Spain from December 1977 to December 1999 as a consequence of near-drowning. PRISM score was calculated for each patient with data obtained upon arrival at the hospital. The probability of death was calculated using this score.

RESULTS

There were 60 patients, divided into two groups as they were admitted to the Pediatric Intensive Care Unit (PICU group, n = 41) or to the Short Stay Unit (SSU group, n = 19). All patients in the SSU group survived without impairments, with PRISM scores <or=8 and a probability of death of 1.3%. All PICU patients with a PRISM score <or=16 or probability of death <or=16% survived without neurologic impairment. Patients with PRISM scores >or=24 or with probability of death >or=42% either died or had serious neurologic impairment. One third of patients with PRISM scores between 17 and 23 and/or probability of death between 16 and 42% either presented serious neurologic impairment or died.

CONCLUSIONS

PRISM score enables the determination of either absence or presence of serious impairment or death in pediatric patients after submersion, if they present extreme values on this scale. However, in patients with intermediate PRISM scores, it is not possible to establish a reliable prognosis.

Wine phenolic antioxidants inhibit AP-1 transcriptional activity

Some of the beneficial effects of moderate wine consumption may be related to the antioxidant properties of polyphenolic compounds containing tannins, flavonoids, and phenolic acids. Cellular actions have recently been reported and may involve the modulation of transcriptional factors such as AP-1 (activator protein-1), which controls the expression of various genes implicated in inflammation processes, cell differentiation, and proliferation. The aim of this study was to evaluate the modulation of AP-1 activity by the phenolic acids (gallic, caffeic, protocatechic, paracoumaric, sinapic, and ferulic acids) that are present in wine and to compare their modulating pathways to those of lipophilic or hydrophilic "chain-breaking" antioxidants (such as DL-alpha-tocopherol or trolox) vitamin C, nitric oxide, and reduced glutathione. AP-1 response was studied on a cell line (MTLN) derived from MCF-7 cells transfected with luciferase gene under TRE sequence control. After stimulation by phorbol 12-myristate 13-acetate (PMA; 100 nM, 6 h, 10(-7) M), luciferase activity was determined by a luminescence method in the presence of luciferine/coenzyme A solution using a luminometer (LKB 1251, Finland). Antioxidants to be tested were incubated with cells in the presence or absence of PMA. Stimulation with PMA resulted in an AP-1-mediated increase in luciferase gene expression corresponding to an 8-fold increase in luciferase activity. After stimulation by PMA, a dose-dependent inhibition of AP-1 was observed with the six phenolic acids in the 20 nM-20 microM concentration range: gallic acid > caffeic > protocatechic, paracoumaric, sinapic acids > ferulic acid. Inhibition was more pronounced with phenolic acids than with DL-alpha-tocopherol (IC(50) = 5 +/- 4.5 microM for gallic acid vs 85 +/- 11 microM for vitamin E). None of the hydrophilic antioxidants inhibited PMA-induced AP-1 activation. None of the antioxidants tested in the absence of PMA stimulation induced any activation or inhibition of AP-1. Our results suggest that phenolic acids may act directly on cell signaling via inhibition of AP-1 transcriptional activity. In addition to preventing LDL oxidation in the arterial wall, our observations indicate that phenolic acids have a cell-mediated capacity to prevent some of the processes involved in atherosclerosis in a plasma concentration range compatible with nutritional intakes.

Self-assembly of the amphipathic helix (VHLPPP)8. A mechanism for zein protein body formation

gamma-Zein, a maize storage protein with an N-terminal proline-rich repetitive domain (gamma-ZNPRD), is located at the periphery of protein bodies. This domain appears to be indispensable for the aggregation of the protein on the surface of the organelle. The peptide (VHLPPP)8, spanning the gamma-ZNPRD, adopts a polyproline II (PPII) conformation that gives an amphipathic helix different from the alpha-helix. We used atomic force microscopy to study the surface organisation of the octamer, and transmission electron microscopy to visualise aggregates of the peptide in aqueous solution. We consider two self-assembly patterns that take account of the observed features. The micellar one fits best with the experimental results presented. Moreover, we found that this peptide has properties associated with surfactants, and form micelles in solution. This spontaneous amphipathic arrangement of the gamma-ZNPRD suggests a mechanism of gamma-zein deposition inside maize protein bodies.

Evidence for the Involvement of annexin 6 in the trafficking between the endocytic compartment and lysosomes

Annexins are a family of calcium-dependent phospholipid-binding proteins, which have been implicated in a variety of biological processes including membrane trafficking. The annexin 6/lgp120 prelysosomal compartment of NRK cells was loaded with low-density lipoprotein (LDL) and then its transport from this endocytic compartment and its degradation in lysosomes were studied. NRK cells were microinjected with the mutated annexin 6 (anx6(1-175)), to assess the possible involvement of annexin 6 in the transport of LDL from the prelysosomal compartment. The results indicated that microinjection of mutated annexin 6, in NRK cells, showed the accumulation of LDL in larger endocytic structures, denoting retention of LDL in the prelysosomal compartment. To confirm the involvement of annexin 6 in the trafficking and the degradation of LDL we used CHO cells transfected with mutated annexin 6(1-175). Thus, in agreement with NRK cells the results obtained in CHO cells demonstrated a significant inhibition of LDL degradation in CHO cells expressing the mutated form of annexin 6 compared to controls overexpressing wild-type annexin 6. Therefore, we conclude that annexin 6 is involved in the trafficking events leading to LDL degradation.

Activation of Raf-1 is defective in annexin 6 overexpressing Chinese hamster ovary cells

Annexin 6 is a Ca2+-dependent phospholipid-binding protein involved in membrane trafficking. In this study we demonstrate the association of Raf-1 with recombinant rat annexin 6. Raf-annexin 6 interaction was shown to be independent of cell activation by epidermal growth factor (EGF) or phorbol esters (12-O-tetradecanoyl-phorbol-13-acetate (TPA)). A stable Chinese hamster ovary (CHO)-anx6 cell line overexpressing annexin 6 was established to examine the function of annexin 6. In these cells, no increase of Ras-GTP levels, induced by EGF or TPA, was detected. In addition, the activity of Raf was completely inhibited, whereas the mitogen-activated protein kinase-P was unaffected.

Stereoisomerism of molecular multipropellers. 2. Dynamic stereochemistry of bis- and tris-triaryl systems

The dynamic stereochemistry of bis- and tris-triaryl systems, the most simple "molecular multipropellers", is discussed on the basis of an extension of a systematic stereochemical analysis based on a symmetry-adapted symbolic notation developed specifically for these molecules. A suitable theoretical basis for our study is provided by the classical hypotheses concerning the dynamics of simple triaryl systems as formulated by Mislow and co-workers (J. Am. Chem. Soc. 1973, 95, 1535-1547), which, once applied to molecular multipropellers, show the existence of two modes of rearrangement for each propeller. Interconversion graphs for all molecules under study, covering a wide span of structural complexity, are presented. A complete NMR study of a two- and a three-propeller molecule indicates that all experimentally observable exchange pathways are indeed predicted by theoretical analysis. Moreover, quantitative analysis of 2D-EXSY experiments affords the activation energy of the subset of pathways that give rise to observable interconversions on the NMR time scale. Assuming that two-ring flips are the threshold mechanism for individual propeller interconversion, the experimental evidence indicates a preference for the flip of the central ring and one of the outer rings over the flip of two outer rings.

Stereoisomerism of molecular multipropellers. 1. Static stereochemistry of bis- and tris-triaryl systems

The static stereoisomerism of bis- and tris-triaryl systems has been analyzed by a systematic stereochemical analysis, and the resulting theoretical predictions have been experimentally confirmed by using reversed-phase HPLC and ESR and (1)H NMR spectroscopies with a family of seven distinct polychlorinated aromatic multipropellers. To analyze the static stereochemistry of these molecules, we have developed a specific procedure that uses a symmetry-adapted symbolic notation, allowing the theoretical prediction of both the number and symmetry of the isomers of the investigated molecules. Due to the steric hindrance introduced by the presence of bulky chlorine substituents, (all) conformational isomers can be characterized experimentally by several independent techniques confirming the theoretical stereochemical predictions. The different propeller moieties that constitute the molecule appear to be nearly independent of each other. Consequently, most of the observed isomers show comparable populations in solution at room temperature.

A graphical method for the analysis of anisotropic rotational diffusion in proteins

A graphical method for the analysis of relaxation data is presented. It allows a fast estimation of the range of values of the components of the axially symmetric rotational diffusion tensor that are compatible with the experimental relaxation data. The graphical method clearly shows the contribution of different experimental relaxation parameters to the measured anisotropy. In particular, for proteins with moderate anisotropy, data from at least two N-H bonds forming angles close to 0 degrees and 90 degrees with respect to the principal axis of the rotational diffusional tensor are needed. For very anisotropic systems, combination of different relaxation parameters from a single residue is enough to characterize the local anisotropy.

Identification and quantification of geosmin, an earthy odorant contaminating wines

Musty, earthy odors are highly detrimental to the aromatic quality of wines. A characteristic aroma of freshly tilled earth, damp cellar was studied in some red and white wines of different origins. The extraction and purification of the wines marked by this odor have shown after analysis by gas chromatography-olfactometry a unique strong odorous zone having the same odor as the one perceived at tasting. The compound responsible for this odorous zone was identified by gas chromatography-mass spectrometry as geosmin (trans-1,10-dimethyl-trans-9-decalol), which possesses a distinctive earthy odor. Geosmin may be present in wines at levels higher than the racemic geosmin olfactory perception threshold, thus suggesting its contribution to their off-aroma. Moreover, the presence of this compound in juice taken from freshly crushed grapes suggests that microorganisms that develop on the grapes may contribute to the presence of this compound in wines.

Epidermal growth factor-mediated caveolin recruitment to early endosomes and MAPK activation. Role of cholesterol and actin cytoskeleton

The endocytic compartment of eukaryotic cells is a complex intracellular structure involved in sorting, processing, and degradation of a great variety of internalized molecules. Recently, the uptake through caveolae has emerged as an alternative internalization pathway, which seems to be directly related with some signal transduction pathways. However, the mechanisms, molecules, and structures regulating the transport of caveolin from the cell surface into the endocytic compartment are largely unknown. In this study, normal quiescent fibroblasts (normal rat kidney (NRK)) were used to demonstrate that epidermal growth factor causes partial redistribution of caveolin from the cell surface into a cellubrevin early endocytic compartment. Treatment of NRK cells with cytochalasin D or latrunculin A inhibits this pathway and the concomitant activation of Mek and mitotic-activated protein (MAP) kinase; however, if cells were pre-treated with filipin, cytochalasin D does not inhibit the phosphorylation of MAP kinase induced by epidermal growth factor. From these results we conclude that in NRK cells the intact actin cytoskeleton is necessary for the EGF-mediated transport of caveolin from the cell surface into the early endocytic compartment and the activation of MAP kinase pathway.

Long-term hydroxytamoxifen treatment of an MCF-7-derived breast cancer cell line irreversibly inhibits the expression of estrogenic genes through chromatin remodeling

Antiestrogen resistance is frequently observed in patients after longterm treatment with tamoxifen, a nonsteroidal antiestrogen widely used for endocrine therapy of breast cancer. In vitro studies in resistant cells showed that the expression of natural estrogen-responsive genes is frequently altered. Using MVLN cells, an MCF-7-derived cell model, we previously demonstrated that 4-hydroxytamoxifen (OHT) treatment irreversibly inactivated an estrogen-regulated chimeric luciferase response by a direct effect of the drug and not through a cell selection process (E. Badia et al., Cancer Res., 54: 5860-5866, 1994). In the present study, we present tamoxifen-resistant but still estrogen-dependent clones isolated after long-term treatment of MVLN cells with OHT and show that progesterone receptor (PR) expression was irreversibly decreased in some of these clones, whereas the PRA:PRB ratio of residual PR remained unchanged. The irreversible inactivation of both chimeric luciferase gene and PR gene expression was associated with the disappearance of DNase 1-hypersensitive sites. In the case of the chimeric gene, at least one of these sites was close to the estrogen responsive element. Genomic sequencing analysis of a clone with very low PR content did not reveal any methylation on CpG dinucleotides or any mutation in the PR gene promoter region. In all of the resistant clones tested and independently of their PR content, estrogen receptor expression was only lowered by half and remained functional, whereas pS2 expression was not modified. We also observed that the residual luciferase activity level (1-2%) of the MVLN clones, the luciferase expression of which had been irreversibly inactivated, was raised 4-fold by trichostatin A treatment. We conclude that long-term OHT treatment may modify the chromatin structure and thus could contribute to differentially silencing natural target genes.

Late endocytic compartments are major sites of annexin VI localization in NRK fibroblasts and polarized WIF-B hepatoma cells

Annexin VI is an abundant calcium- and phospholipid-binding protein whose intracellular distribution and function are still controversial. Using a highly specific antibody, we have studied the distribution of annexin VI in NRK fibroblasts and the polarized hepatic cell line WIF-B by confocal microscopy. In NRK cells, annexin VI was almost exclusively found associated with endocytic compartments, which were defined by their ability to receive fluid-phase marker internalized from the cell surface. However, extensive colocalization of annexin VI and the endocytic marker was only observed after about 45 min, indicating that annexin VI was primarily in late endocytic compartments or (pre)lysosomes. Consistent with this, annexin VI was predominantly seen on structures that contained the lysosomal protein lgp120, although not on dense core lysosomes by electron microscopy. Two major populations of annexin VI-containing structures were present in polarized WIF-B hepatocytes. One correlated to lgp120-positive (pre)lysosomes and was still observed after treatment with brefeldin A (BFA), while the other appeared to be partially associated with Golgi membranes and was BFA-sensitive. The striking association with prelysosomal compartments in NRK and WIF-B cells suggests that annexin VI could play a role in fusion events in the late endocytic pathway, possibly by acting as a tether between membranes.

[Electrophysiologic and anatomic atrial remodeling: an atrial rhythmic cardiomyopathy]

In 1995, Wijffels and Alessie, using a curious goat model of atrial fibrillation, introduced the concept of atrial remodelling. The classical atrial substrate (anatomopathological-dilatation and hypokinesis-, and electrophysiological-short refractory periods and decreased conduction-), appeared not only to be one of the causes of atrial fibrillation but also the consequence of atrial fibrillation itself, the mechanism being a vicious circle. In addition to ventricular rhythmic cardiomyopathy, responsible for cardiac failure, the concept of atrial rhythmic cardiomyopathy with the same mechanical and electrophysiological consequences, has developed. These changes, characterised mainly by calcium overload associated with cellular hibernation and differentiation, have not been totally elucidated but have already renewed the physiopathology of atrial fibrillation.

Cellubrevin is present in the basolateral endocytic compartment of hepatocytes and follows the transcytotic pathway after IgA internalization

The endocytic compartment of polarized cells is organized in basolateral and apical endosomes plus those endocytic structures specialized in recycling and transcytosis, which are still poorly characterized. The complexity of the various populations of endosomes has been demonstrated by the exquisite repertoire of endogenous proteins. In this study we examined the distribution of cellubrevin in the endocytic compartment of hepatocytes, since its intracellular location and function in polarized cells are largely unknown. Highly purified rat liver endosomes were isolated from estradiol-treated rats, and the early/sorting endosomal fraction was further subfractionated in a multistep sucrose density gradient, and studied. Analysis of dissected endosomal fractions showed that cellubrevin was located in early/sorting endosomes, with Rab4, annexins II and VI, and transferrin receptor, but in a specific subpopulation of these early endosomes with the same density range as pIgA and Raf-1. Interestingly, only in those isolated endosomal fractions, endosomes enriched in transcytotic structures (of livers loaded with IgA), the polymeric immunoglobulin receptor specifically co-immunoprecipitated with cellubrevin. In addition, confocal and immuno-electron microscopy identification of cellubrevin in tubular structures underneath the sinusoidal plasma membrane together with the re-organization of cellubrevin, in the endocytic compartment, after the IgA loading, strongly suggest the involvement of cellubrevin in the transcytosis of pIgA.