New tricks for an old pathway: emerging Notch-based biotechnologies and therapeutics

The Notch pathway regulates a diverse array of cell fate decisions, making it an enticing target in cancer therapy and regenerative medicine. During the early stages of Notch drug development, off-target toxicity precluded the approval of Notch inhibitors for the treatment of cancer. However, recent advances in our understanding of Notch structure and signaling have led to the development of several innovative Notch-based biotechnologies. In addition to new classes of inhibitors, pharmacological Notch activators have been shown to enhance osteogenesis and various aspects of T cell function. Furthermore, the mechanosensitive negative regulatory region (NRR) of the Notch receptor has been converted into synthetic Notch (synNotch) receptors with fully customizable signaling circuits. We review emergent Notch-based compounds, biologics, and cell therapies while highlighting the challenges and opportunities they face on the path to clinical development.

Highly Parallelized Screening of Functionally Enhanced XNA Aptamers in Uniform Hydrogel Particles

Xeno-nucleic acid (XNA) aptamers based on evolvable non-natural genetic polymers hold enormous potential as future diagnostic and therapeutic agents. However, time-consuming and costly procedures requiring the purification of individual XNA sequences produced by large-scale polymerase-mediated primer extension reactions pose a major bottleneck to the discovery of highly active XNA motifs for biomedical applications. Here, we describe a straightforward approach for rapidly surveying the binding properties of XNA aptamers identified by in vitro selection. Our strategy involves preparing XNA aptamer particles in which many copies of the same aptamer sequence are distributed throughout the gel matrix of a polyacrylamide-encapsulated magnetic particle. Aptamer particles are then screened by flow cytometry to assess target binding affinity and deduce structure-activity relationships. This generalizable and highly parallel assay dramatically accelerates the pace of secondary screening by allowing a single researcher to evaluate 48-96 sequences per day.

Affinity-matured DLL4 ligands as broad-spectrum modulators of Notch signaling

The Notch pathway regulates cell fate decisions and is an emerging target for regenerative and cancer therapies. Recombinant Notch ligands are attractive candidates for modulating Notch signaling; however, their intrinsically low receptor-binding affinity restricts their utility in biomedical applications. To overcome this limitation, we evolved variants of the ligand Delta-like 4 with enhanced affinity and cross-reactivity. A consensus variant with maximized binding affinity, DeltaMAX, binds human and murine Notch receptors with 500- to 1,000-fold increased affinity compared with wild-type human Delta-like 4. DeltaMAX also potently activates Notch in plate-bound, bead-bound and cellular formats. When administered as a soluble decoy, DeltaMAX inhibits Notch in reporter and neuronal differentiation assays, highlighting its dual utility as an agonist or antagonist. Finally, we demonstrate that DeltaMAX stimulates increased proliferation and expression of effector mediators in T cells. Taken together, our data define DeltaMAX as a versatile tool for broad-spectrum activation or inhibition of Notch signaling.

Chemical parameters and antioxidant activity of turning color natural-style table olives of the Sigoise cultivar

A chemical characterization of turning color table olives of the Sigoise variety was made through their processing as natural-style. Polyphenols, sugars, tocopherols, fatty acids, and antioxidant activity in the olives were monitored throughout the elaboration process. Oleuropein, salidroside, hydroxytyrosol 4-glucoside, rutin, ligustroside and verbascoside showed a decrease of 16.90-83.34%, while hydroxytyrosol increased during the first months of brining. Glucose was consumed by 90% due to the metabolism of the fermentative microbiota. The tocopherol content remained stable during the process and only the α-tocopherol decreased. The fatty acids were not affected. The loss in antioxidant compounds resulted in a decrease in the percentage of DPPH radical inhibition from 75.91% in the raw fruit to 44.20% after 150 days of brining. Therefore, the turning color natural table olives of the Sigoise variety are a good source of bioactive compounds.

Role of lactic acid bacteria in fermented vegetables

The consumption of fermented vegetables is widespread throughout the world and represents an important component of the human diet with considerable contribution to the food supply for a world popula­tion in continuous growth. Many of the fermented vegetables share a general process which requires salting and acidification steps. Among the microorganisms responsible for fermentation, lactic acid bacteria are the most relevant with important organoleptic, quality and safety benefits. This review deals with the microbial ecology of fermented vegetables focusing on the biodiversity of lactic acid bacteria, the most important molecular tech­niques used for their identification and genotyping, their importance for the formation of biofilms as well as their use as starter cultures for obtaining high-quality and safe vegetable products.

Intrinsic Rashba coupling due to hydrogen bonding in DNA

We present an analytical model for the role of hydrogen bonding on the spin-orbit coupling of a model DNA molecule. Here, we analyze in detail the electric fields due to the polarization of the hydrogen bond on the DNA base pairs and derive, within a tight binding analytical band folding approach, an intrinsic Rashba coupling which should dictate the order of the spin active effects in the chiral-induced spin selectivity effect. The coupling found is ten times larger than the intrinsic coupling estimated previously and points out to the predominant role of hydrogen bonding in addition to chirality in the case of biological molecules. We expect similar dominant effects in oligopeptides, where the chiral structure is supported by hydrogen-bonding and bears on orbital carrying transport electrons.

Assessment of the bacterial community in directly brined Aloreña de Málaga table olive fermentations by metagenetic analysis

This study uses an "omics" approach to evaluate the bacterial biodiversity changes during fermentation process of natural green cracked Aloreña de Málaga table olives, from raw material to fermented fruit. For this purpose, two industries separated by almost 20km in Guadalhorce Valley (Málaga, Spain) were analysed for obtaining both brines and fruit samples at different moments of fermentation (0, 7, 30 and 120days). Physicochemical and microbial counts during fermentation showed the typical evolution of this type of processes, apparently dominated by yeasts. However, high-throughput barcoded pyrosequencing analysis of V2-V3 hypervariable region of the bacterial 16S rRNA gene showed at 97% identity the presence of 131 bacterial genera included in 357 operational taxonomic units, not detected by the conventional approach. The bacterial biodiversity was clearly higher in the olives at the moment of reception in the industry and during the first days of fermentation, while decreased considerably as elapse the fermentation process. The presence of Enterobacteriaceae and Lactobacillaceae species was scarce during the four months of study. On the contrary, the most important genus at the end of fermentation was Celerinatantimonas in both brine (95.3% of frequency) and fruit (89.4%) samples, while the presence of well-known spoilage microorganisms (Pseudomonas and Propionibacterium) and halophilic bacteria (Modestobacter, Rhodovibrio, Salinibacter) was also common during the course of fermentation. Among the most important bacterial pathogens related to food, only Staphylococcus genus was found at low frequencies (<0.02% of total sequences). Results show the need of this type of studies to enhance our knowledge of the microbiology of table olive fermentations. It is also necessary to determine the role played by these species not previously detected in table olives on the quality and safety of this fermented vegetable.

Heterogeneity of elemental composition and natural abundance of stables isotopes of C and N in soils and leaves of mangroves at their southernmost West Atlantic range

Mangrove communities were selected in the state of Santa Catarina, Brazil, near their southernmost limit of distribution, to study mineral nutrient relation in soils and plants. Communities included three true mangrove species, Rhizophora mangle, Laguncularia racemosa and Avicennia germinans, and two associated species, the fern Acrostichum danaeifolium, and the grass Spartina densiflora. The sites included communities in the lower Río Tavares near Florianopolis city, Sonho beach near Palhoça city, and the Santo Antonio lagoon. These sites included a full range of mangroves under humid climate where winter temperatures, instead of salinity, may be the main factor regulating their productive capacity and species composition. Soil salinity was determined by the concentration of soluble Na, and soil C and N were linearly correlated indicating their association in organic matter. Tavares site showed higher specific conductivity, and concentrations of Na and Mg in the soil layer below 40 cm depth, indicating larger influence of marine water. Isotopic signature of C increased with soil depth suggesting that microorganisms decomposing organic matter are releasing 13C depleted CO2. Nitrogen isotopic signature decreased with soil depth, indicating enrichment in 15N possibly as a result of denitrification in the upper soil layers. Mineral elements in leaf tissues showed A. schaueriana with higher concentrations of N, P, Na, K, Cu, Zn, and Na/Ca ratio. Spartina densiflora was characterized by the lowest N and K concentrations, and the highest concentrations of Al and Fe. Rhizophora mangle and L. racemosa had the highest Ca concentrations. Carbon isotopic signatures identified S. densiflora as a C4 plant, and A. schaueriana as the mangrove species occupying comparatively more water stressed microsites than the rest. Leaf nitrogen isotopic signatures were positive, in correspondence with the soil values. The results support the hypothesis that sites sampled were comparatively fertile, because sediment transport through fresh water run-off is predominant in humid coasts, and therefore plants were not limited by nutrient supply, nor particularly stressed by soil salinity.

Staphylococcus aureus develops increased resistance to antibiotics by forming dynamic small colony variants during chronic osteomyelitis

OBJECTIVES

Staphylococcus aureus osteomyelitis often develops to chronicity despite antimicrobial treatments that have been found to be susceptible in in vitro tests. The complex infection strategies of S. aureus, including host cell invasion and intracellular persistence via the formation of dynamic small colony variant (SCV) phenotypes, could be responsible for therapy-refractory infection courses.

METHODS

To analyse the efficacy of antibiotics in the acute and chronic stage of bone infections, we established long-term in vitro and in vivo osteomyelitis models. Antibiotics that were tested include β-lactams, fluoroquinolones, vancomycin, linezolid, daptomycin, fosfomycin, gentamicin, rifampicin and clindamycin.

RESULTS

Cell culture infection experiments revealed that all tested antibiotics reduced bacterial numbers within infected osteoblasts when treatment was started immediately, whereas some antibiotics lost their activity against intracellular persisting bacteria. Only rifampicin almost cleared infected osteoblasts in the acute and chronic stages. Furthermore, we detected that low concentrations of gentamicin, moxifloxacin and clindamycin enhanced the formation of SCVs, and these could promote chronic infections. Next, we treated a murine osteomyelitis model in the acute and chronic stages. Only rifampicin significantly reduced the bacterial load of bones in the acute phase, whereas cefuroxime and gentamicin were less effective and gentamicin strongly induced SCV formation. During chronicity none of the antimicrobial compounds tested showed a beneficial effect on bone deformation or reduced the numbers of persisting bacteria.

CONCLUSIONS

In all infection models rifampicin was most effective at reducing bacterial loads. In the chronic stage, particularly in the in vivo model, many tested compounds lost activity against persisting bacteria and some antibiotics even induced SCV formation.

Characterization of the microbial diversity in yacon spontaneous fermentation at 20 °C

The prebiotic fructooligosaccharide content of yacon makes this root an attractive alternative for the supplementation of a variety of food products. The preservation of yacon by fermentation has been proposed as an alternative to increase the probiotic content of the root concomitantly with its shelf life. Thus the fermented yacon could have significant functional content. The objective of this research was to characterize the biochemistry and microbiology of spontaneous yacon fermentation with 2% NaCl and define the viability of the proposed process. The biochemical analysis of spontaneous heterolactic fermentation of yacon showed a progressive drop in pH with increased lactic and acetic acids, and the production of mannitol during fermentation. The microbial ecology of yacon fermentation was investigated using culture-dependent and culture-independent methods. Bacterial cell counts revealed a dominance of lactic acid bacteria (LAB) over yeasts, which were also present during the first 2 days of the fermentation. Results showed that the heterofermentative LAB were primarily Leuconostoc species, thus it presents a viable method to achieve long term preservation of this root.

The complete picture of changing pediatric inflammatory bowel disease incidence in Spain in 25 years (1985-2009): the EXPERIENCE registry

OBJECTIVES

A growing incidence of pediatric IBD (PIBD) in southern Europe has been recently reported. The SPIRIT registry (1996-2009) confirmed these tendencies in Spain. Our aim is to obtain data from 1985 to 1995 and describe the complete picture of PIBD presentation changes in Spain in the last 25years.

METHODS

A retrospective survey of incident PIBD in the period 1985-1995 was performed. Patients' data were obtained from the hospitals' databases and compared with the published data from the 1996 to 2009 period. Seventy-eight IBD reference centers took part in this survey.

RESULTS

Data from 495 patients were obtained: 278 CD (56.2%), 198 UC (40%), and 19 IBDU (3.8%); 51.7% were female, with higher predominance both in UC (58.6%) and in IBDU (57.9%), but not in CD (46.4%). Median (IQR) age at diagnosis was 12.9 (10.0-15.7) years, with significant differences among IBD subtypes: CD: 13.1 (10.8-16.0) vs UC: 12.4 (9.4-15.1) vs IBDU: 7.5 (3.0-13.0) (p≤0.001). These results are significantly different to the ones in the SPIRIT registry, with a higher proportion of IBDU, younger age and male predominance. The data from both periods taken together give a complete picture of a 25-year period. An annual increase of incident patients was observed, with a ten-fold increase over this period.

CONCLUSION

These data extend the epidemiological trends to a full 25-year period (1985-2009). PIBD incidence in Spain has experienced a sixteen-fold increase. The IBD subtype, localization of the affected segment, age- and sex distribution observed are in accordance with our previously published ones of 1996-2009.

First Report of Phytophthora infestans Causing Late Blight on Solanum viarum in Colombia

Solanum viarum Dunal (tropical soda apple) belongs to the section Acanthophora in the genus Solanum, which includes nearly 20 neotropical species of herbs and small shrubs (2). The species in this section are sometimes called the 'spiny Solanums' (2) and are adapted mainly to highly disturbed habitats and open secondary forests. The center of diversity is eastern Brazil (3). Since the early 1990s, S. viarum has been a problematic weed in Florida where it was listed as a noxious weed in 1993, followed in 1994 by its addition to the Federal Noxious Weed List of the USDA. On 17 April 2010, 12 plants of S. viarum located close to a S. betaceum crop (tree tomato) in the province of Caldas (Department of Antioquia, central northwestern Colombia) were found with symptoms similar to late blight caused by Phytophthora infestans on S. tuberosum (potato). Fifteen leaves from 12 plants with blackish, water-soaked lesions showing a white sporulation on the abaxial side were collected and processed within 3 days. The leaves were placed in a humid chamber and incubated in darkness at room temperature (18°C mean temperature) until sporulation was observed. Microscopic characteristics were consistent with Phytophthora spp. Only one axenic culture was obtained by successive subcultures in rye B agar plates. After an incubation period of 8 days, plates were washed with distilled water and ovoid, semipapillate caduceus sporangia ranging from 38 to 41 μm long (average 39; N = 86) and 23 to 29 μm wide (average 26; N = 86) were observed. To fulfill Koch's postulates and test the isolate for the ability to infect potato as well as Solanum spp. associated with potato crops in Colombia, triplicate pathogenicity tests were carried out on three detached leaves of S. viarum, S. tuberosum, and S. americanum (American nightshade). A 1 × 10⁴ sporangia/ml suspension of the Phytophthora isolate, estimated using a haemocytometer, was obtained from 8-day-old cultures grown on rye B agar. The suspension was incubated at 4°C for 2 h to induce zoospore release. The leaves were then inoculated by spraying them until runoff. After an incubation period of 5 days at 18°C in a humidity chamber, mycelia, sporangia, and brownish lesions, similar to those described above, were observed in the leaves of all three hosts, indicating pathogenicity. DNA extraction was performed from the P. infestans isolate (4). Four nuclear loci, ITS, β-tubulin, Ras, and Avr3a, as well as one mitochondrial gene, cytochrome c oxidase 1 (Cox1), were amplified and sequenced. Sequences were compared with GenBank databases using Blastn. In all cases, the best hits corresponded to P. infestans (GenBank Accession No. HQ639930 for Avr3A, HQ639931 for β-tubulin, HQ639932 for Cox1, HQ639933 for iRas, HQ639934 for Ras, and JF419363 for ITS). Reports of P. infestans causing typical late blight symptoms on wild solanaceous plants are becoming more frequent and have been made from other countries such as Peru (1). To our knowledge, this is the first time that P. infestans has been observed and isolated from S. viarum in Colombia, introducing the possibility of this wild solanaceous weed as another late blight host. References: (1) G. Garry et al. Eur. J. Plant Pathol. 113:71, 2005. (2) R. Levin et al. Am. J. Bot. 92:603, 2005. (3) M. Nee. A Revision of Solanum Section Acanthophora. Ph.D. diss. University of Wisconsin, Madison, 1979. (4) A. M. Vargas et al. Phytopathology 99:82, 2009.

Bipolar disorder therapy in daily clinical practice: Analysis of retrospective data from a large multinational longitudinal study (WAVE-BD)

Introduction

The Wide AmbispectiVE study of clinical management and burden of bipolar disorder (BD) (WAVE-bd; NCT01062607) is ongoing to address limitations of longitudinal BD studies to-date focused on single disease phases or treatment.

Aim/Objective

To understand current treatment approaches for patients with BD in daily clinical practice.

Methods

Multinational, multicentre, non-interventional, longitudinal study of patients diagnosed with BD-I or BD-II with ≥1 mood event in the preceding 12 months, followed-up for 12-27 months (including retrospective and prospective phases). Site and patient selection provided a sample representative of bipolar populations. The study includes descriptive analyses of demographics, diagnosis, medical history and clinical management. Medication use during the retrospective phase will be presented.

Results

Preliminary results (based on data availability at time of submission) are presented from 2829 patients recruited March-September 2010. During the retrospective period, 94.3% (94.2% BD-I, 94.6% BD-II) of patients received BD therapy. Among BD-I and BD-II patients, respectively, the most common number of prescribed drugs was two (29.5%, 31.5%); 17.6% and 18.1% were prescribed one drug, and 11.5% and 9.8% were prescribed five or more. Drug classes most commonly used (BD-I, BD-II, respectively) were atypical antipsychotics (64.5%, 48.9%) anticonvulsants (58.0%, 54.3%), antidepressants (39.6%, 66.7%) and lithium (31.2%, 17.3%). Electroconvulsive therapy was used in 12 (0.4%) patients (9 BD-I, 3 BD-II). Average treatment duration with atypical antipsychotics, anticonvulsants and antidepressants was 165.0, 199.7 and 169.7 days, respectively.

Conclusions

This ongoing study provides a multinational perspective on BD patient management practices in a large sample population. Financial support: AstraZeneca

Patterns of disease and severity in bipolar disorder: Retrospective data from a large multinational longitudinal study (WAVE-bd)

Introduction

The Wide AmbispectiVE study of the clinical management and burden of bipolar disorder (BD) (WAVE-bd; NCT01062607) is ongoing to address limitations of longitudinal BD studies to-date focused on single disease phases or treatment.

Aim/Objective

To describe baseline bipolar mood state and severity in a cohort of patients with BD.

Methods

Multinational, multicentre, non-interventional, longitudinal study of patients diagnosed with BD-I or BD-II with ≥1 mood event in the preceding 12 months (retrospective data collection from index mood event to enrolment, followed by 9-14 months’ prospective follow-up). Site and patient selection provided a sample representative of bipolar populations. The study includes descriptive analyses of demographics, diagnosis and medical history.

Results

2880 patients (mean age 46.5 years [SD: 13.3]; 62.0% female) were recruited March to September 2010: 1989 (69.1%) BD-I and 891 (30.9%) BD-II. Time (years) from first symptoms to diagnosis was 2.9 [SD: 6.6] (BD-I) and 4.4 [SD: 8.0] (BD-II). Of the total population, 20.8% lived alone (13.9% BD-I, 6.9% BD-II), 36.7% were employed (24.0% BD-I, 12.7% BD-II) and 13.3% unemployed (9.5% BD-I, 3.8% BD-II). Disease status at inclusion (BD-I, BD-II, respectively [mild, moderate, severe]) included hypomania (7.9% [67.7%, 31.0%, 1.3%], 6.5% [70.7%, 29.3%, 0%]), mania (7.1% [26.1%, 47.2%, 26.8%], 0%), euthymia (58.6%, 60.3%), depression (19.7% [38.8%, 47.7%, 13.5%], 31.1% [41.2%, 46.9%, 11.9%]) and mixed (5.7% [30.1%, 46.9%, 23.0%], 0%).

Conclusions

This ongoing study provides detailed insight into a large BD population, showing the majority with euthymia and an important proportion with depression both in BD-I and BD-II patients.

Spent mushroom substrates as component of growing media for germination and growth of horticultural plants

This research work was conducted in order to investigate the possibility of using spent mushroom substrate (SMS) in the production of horticultural seedlings replacing part of the peat in the growing media. Three vegetable species with different salt sensitivities, the less sensitive being tomato (Lycopersicon esculentum var. Muchamiel), the moderately salt-sensitive being courgette (Cucurbita pepo L. var. Afrodite F1) and the most salt-sensitive being pepper (Capsicum annum L. var. Lamuyo F1) were grown in 12 media containing SMS of two types of mushroom (Agaricus bisporus (SMS-AB) and Pleurotus ostreatus (SMS-PO)) or a mixture of both 50% (v/v) (SMS-50), as well as peat in various ratios. The proportions of each residue in the mixtures elaborated with peat were 25%, 50%, 75% and 100% v/v residue. A substrate of 100% peat was used as control. The experiment was arranged in a completely-randomised design with two replicates per treatment under greenhouse conditions. Prior to sowing, some physical, physico-chemical and chemical properties of the growing media were determined and seed germination and fresh weight of seedling were also measured. In most of the cases, the addition of SMS to the growing media produced an increase in the pH values, salt contents, macro and micronutrient concentrations and a decrease in the water holding capacity contents in comparison to peat, whereas great differences were found in the air capacity values between SMS-based substrates and peat. Up to 75% SMS can be used in mixtures with peat for seed germination of the plant species studied. Regarding the most suitable SMS-based substrates for plant growth, any substrate could be used for tomato seedling production. However, all SMS-AB-based substrates and the media containing low dose of SMS-PO and SMS-50 were adequate for growth of courgette and pepper.

Effect of sunitinib on TRAIL-induced apoptosis in preclinical colon cancer models

e14633

Background: Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) is a potent inducer of apoptosis, however not all cancers respond to TRAIL, which may be due to activation of survival signals. Sunitinib is a potent inhibitor of multiple receptor tyrosine kinases, including vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR). These receptors and their signaling cascades promote cell survival and drug resistance. Inhibition of these pathways with sunitinib may augment TRAIL-mediated apoptosis. Aims: 1) Determine sensitivity of colon cancer cell lines to the combination of TRAIL and sunitinib, 2) identify mechanism by which sunitinib enhances TRAIL-mediated apoptosis, and 3) investigate the anticancer activity of this drug combination in xenograft models. Methods & Results: Sunitinib enhanced the anticancer activity of TRAIL in HCT116 and HCT15 colon cancer cell lines, with increased caspase cleavage and DNA fragmentation using western blot analysis and propidium iodide staining, respectively. Overexpression of Bcl-2 in HCT116 cells reduced TRAIL+sunitinib-mediated apoptosis, suggesting that sunitinib enhances TRAIL-induced apoptosis via activation of the mitochondrial apoptotic pathway. Sunitinib enhanced TRAIL-induced JNK activation, which may play a role in TRAIL+sunitinib-mediated apoptosis. Xenograft models of HCT116 and HCT15 were established in nude mice and treated with TRAIL, sunitinib, or the combination. The TRAIL+sunitinib combination significantly reduced tumor burden in both xenograft models compared to either treatment alone. The reduction in tumor volume correlated with increased apoptosis and decreased tumor proliferation and angiogenesis as determined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and immunohistochemistry for Proliferating Cell Nuclear Antigen and VEGF. Conclusion: These results are the first to demonstrate that simultaneous treatment with TRAIL and sunitinib reduced cell viability, induced apoptosis, inhibited tumor proliferation and angiogenesis in both in vitro and in vivo models of colon cancer, and warrants further investigation.

No significant financial relationships to disclose.

Endoscopic pneumatic balloon dilation in primary achalasia: predictive factors, complications, and long-term follow-up

Pneumatic dilation (PD) has been widely used in the treatment of idiopathic achalasia with a 70-90% response. The aim of this study was to evaluate the effectiveness of PD and its predictive factors by means of clinical assessment. In addition, we evaluated its safety and the need for subsequent surgical intervention. Fifty-six patients were treated with a Witzel dilator. The response was evaluated at medium (1-5 years) and long term (>5 years). Diverse possible predictive factors to response were analyzed. After the first PD, 85.7% of the 56 patients improved and passed from clinical stage II-III to clinical stage 0-I (P < 0.005). After the second dilation, 84.6% of the patients (13) passed to clinical stage 0-I (P < 0.05). Only patients who were not young (>40 years) avoided a second dilation and/or surgery (P < 0.001). During the first 5 years of follow-up, 80% of patients maintained their response; this percentage decreased to 58% after 10 years. PD therapy of achalasia is a safe technique, with few adverse effects (4% perforations and 10% gastroesophageal reflux). It offers a medium-term response of 80% and long-term response of around 60%. Age was the only predictive response factor.

Multiple Factor Analysis of the Autonomous Nervous System during PTCA

This study describes the Autonomic Nervous System (ANS) response before, during and after a percutaneous transluminal coronary angioplasty (PTCA). The study population consisted of 37 patients undergoing PTCA from Staff-3 Database. Classical Heart rate variability (HRV) parameters: RR mean, SD, rMSSD, LF, HF, LF/HF and LF/(HF+LF) were extracted and a multiple factorial analysis (MFA) was carried out. Preliminary results show that sympathetic activity increases during and after PTCA, and global HRV decreases during PTCA and increases after PTCA. These findings suggest that MFA provides a powerful tool allowing assessment of ANS's response during PTCA.

[Complications of endoscopic retrograde cholangiopancreatography in patients aged more than 90 years old]

INTRODUCTION

To evaluate the effectiveness of endoscopic retrograde cholangiopancreatography (ERCP) and the complication rates of this procedure in patients aged 90 years and older.

PATIENTS AND METHOD

A descriptive, prospective study including 42 endoscopic procedures performed from first January 2001 until first June 2004 in 36 patients (7 males and 29 females) was performed. The mean age was 91 years (range 90-96 years). All patients underwent the following: a) clinical evaluation before and after endoscopic exploration; b) evaluation of the success or failure of the endoscopic procedure and c) assessment of complications (perforation, hemorrhage, pancreatitis and infection). Concurrent associated illnesses, as well as the existence of anatomical alterations in Vaters papilla (duodenal diverticula), were also evaluated.

RESULTS

ERCP was successful in 85.7% of all explorations performed. Twenty-three patients (63.8%) had one or more major associated diseases. In 15 patients (33.3%) Vaters papilla was associated with duodenal diverticula. The complication rates were as follows: 1) acute pancreatitis in 2 explorations (4.7%), one mild (2.35%) and the other moderate (2.35%); 2) hemorrhage after endoscopic sphincterotomy in 2.8% of patients (1/35); 3) bacteriemia in one patient (2.3%) and cholangitis in one patient (2.3%), with no cases of secondary cholecystitis; 4) hypoxemia in one patient. There were no perforations or deaths related to the procedure.

CONCLUSION

ERCP is a safe and effective technique with a low complication rate in patients aged 90 years or older.

Quilotórax bilateral masivo en postoperatorio de gastrectomía subtotal

Chylothorax is a lymphatic effusion of chylous in the pleural space due to thoracic duct obstruction or injury. The most frequent aetiology is cancer; it is also related to chest trauma and iatrogenic. We describe the case of bilateral chylothorax in a 76-year-old woman, right predominant, during the post-operational phase of gastric surgery. This presented itself with respiratory insufficiency and tachycardia without initial haemodynamic compromise. It presented a favourable evolution after conservative treatment, cessation of oral intake and TPN and chest tube during 10 to 14 days.

Intranasal vaccination with streptococcal fibronectin binding protein Sfb1 fails to prevent growth and dissemination of Streptococcus pyogenes in a murine skin infection model

Fibronectin binding protein F1 (Sfb1) of Streptococcus pyogenes (group A streptococcus [GAS]) is a well-characterized adhesin that has been shown to induce protection in mice against a lethal intranasal GAS challenge after intranasal immunization with cholera toxin B subunit (CTB) as adjuvant. With a murine skin infection model, we have shown that Sfb1/CTB vaccination neither elicits opsonizing antibodies nor prevents systemic bacterial growth and dissemination to internal organs after a subcutaneous GAS challenge. These results indicate that an Sfb1-based vaccine should be complemented with additional protective antigens in order to be used in areas such as the tropical north of Australia, where the skin is the primary route of entry for invasive streptococcal diseases.

Ionic shell and subshell structures in aluminum and gold nanocontacts

Conductance histograms of aluminum and gold nanocontact rupture are studied experimentally and simulated using embedded atom potentials to assess the interplay between electronic and structural properties at room temperature. Our results reveal a crossover from quantized conductance structures to crystalline faceting or geometric shell/subshell structures at 300 K. The absence of electronic shell structure in gold and aluminum is in stark contrast with the behavior of alkaline metal nanowires which emulate their cluster counterparts. Semiclassical arguments suggest why rapid dominance of ionic structures takes place, and possible nanowire architectures are proposed in consistency with both the experimental and simulated nanocontact data.

[Trihalomethanes in the drinking water of Carabobo State, Venezuela]

OBJECTIVE

Disinfection of water with chlorine in water treatment plants leads to the formation of trihalomethanes (THMs). These compounds are associated with adverse health effects. The aim of this study was to analyze THM concentrations in the water provided for human consumption in the two main water treatment systems of Carabobo State: the Alejo Zuloaga plant and the Pao-Cachinche reservoir, which form the Central Regional System I (CRS I), and the Lucio Baldo Soules plant and the Pao-La Balsa reservoir, which form the Central Regional System II (CRS II).

METHODS

We analyzed 144 water samples collected in 6 samplings carried out in 2000 and 2001. THM concentrations were determined by gas chromatography using the headspace technique. The concentrations of the following THMs were measured: chloroform (CHCl3), bromoform (CHBr3), chlorodibromomethane (CHBr2Cl) and bromodichloromethane (CHCl2Br).

RESULTS

The concentration of total THMs was between 47.84 g/l and 94.23 g/l. CHCl3 was the most commonly formed compound representing 83% of all THMs in the CRS I and 82% in the CRS II. The concentrations of total THMs in the CRS I, specifically in the Baja and San Diego networks, were significantly higher (p < 0.05) than permissible levels set by the American Environmental Protection Agency (80 g/l) for the sum of all four THMs.

CONCLUSIONS

The results show that in the area studied there is a risk of adverse health effects due to THMs in drinking water, especially in the Baja and San Diego networks.

Prospective evaluation of magnetic resonance cholangiopancreatography in patients with biliary disease: comparative study with conventional ultrasonography and endoscopic retrograde cholangiopancreatography diagnostic algorithm

BACKGROUND

Magnetic resonance cholangiopancreatography is an accurate technique that can replace invasive diagnostic methods of the biliary and pancreatic duct.

AIMS

Our aim was to assess sensitivity and specificity of magnetic resonance cholangiopancreatography and ultrasonography using the results of endoscopic retrograde cholangiopancreatography as reference, and to establish a diagnostic algorithm under which circumstances magnetic resonance cholangiopancreatography can replace endoscopic retrograde cholangiopancreatography.

PATIENTS

Eighty-three patients with suspicion of biliary disease based on clinical, biochemical and ultrasonography findings were studied.

METHODS

Ultrasonography, magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography were performed, comparing the results of the techniques for the determination of their sensitivity and specificity.

RESULTS

Sensitivity and specificity results obtained by magnetic resonance cholangiopancreatography were: 100 and 92.8% when dilated ducts were detected (n=61); 97.4 and 97.2% in the diagnosis of choledocholithiasis (n=38); 100 and 96.7% in malignant lesions (n=14) and 81.8 and 98.4% when biliary ducts were normal. The percentage of images of diagnostic quality was 97.6%. Sensitivity and specificity achieved by ultrasonography was: 100 and 57.1% in detection of dilatation, 71 and 97.2% in choledocholithiasis, 92.8 and 96.7% in malignancy and 66.6 and 96.8% in normal ducts.

CONCLUSIONS

Magnetic resonance cholangiopancreatography is a technique with high sensitivity and specificity in the evaluation of biliary ducts. Thus, magnetic resonance cholangiopancreatography may replace diagnostic endoscopic retrograde cholangiopancreatography for purely diagnostic purposes, following an initial clinical and ultrasonographic exam.

Identificación de las variables de influencia en los tiempos de espera en atención especializada

OBJECTIVE

To identify the variables influencing waiting time for specialized care (waiting lists) through multiple regression analysis and to analyze the health districts with long waiting times according to these variables.

DESIGN

Descriptive, cross sectional and retrospective study of waiting times for access to specialized care between 1997 and 1998.

SETTING

Area 20 of the Health Department of the Autonomous Community of Valencia (Spain) consisting of 12 health districts with 204,424 inhabitants.

INTERVENTIONS

The following variables were gathered: variables influencing demand: type of municipality, aging and indexes of dependent population, and percentage of pensioners; variables influencing supply: age, sex, training and professional stability of the doctor, and size of the patient list; variables influencing resource consumption: percentage of referrals to specialized care per thousand inhabitants, mean WT for access to specialized care (in natural days) by district and year, number of consultations, and workload. A multiple regression model was constructed through (backward) elimination, taking the mean WT as the dependent variable and the remaining variables as independent variables. The resulting equation enabled calculation of the expected WT per health district and the deviation of the real WT from the expected WT. A district was considered to have a high WT when its deviation was above the mean plus one standard deviation of the distribution.

RESULTS

The mean WT for access to specialized care was 37 days in 1997 and 34 days in 1998. A significant correlation (p < 0.005) was found between WT and the percentage of the population aged less than 14 years (r = 0.693), the percentage of the population aged between 14-65 years (r = 0.517), the number of consultations (r = 0.689), and coastal population (r = 0.470). Our final model included: percentage of the population aged less than 14 years, number of consultations, and coastal population (F = 41.803; p < 0.000; r = 0.945; r2 = 0.893). Three districts (37.5%) with high WTs were identified.

CONCLUSIONS

The number of consultations, the percentage of the pediatric population, and proximity to the coast were closely correlated with WT for specialized care, with a consequent influence on waiting lists.

Viscosity minimum in bimodal concentrated suspensions under shear

We study a model of concentrated suspensions under shear in two dimensions. Interactions between suspended particles are dominated by direct-contact viscoelastic forces and the particles are neutrally bouyant. The bimodal suspensions consist of a variable proportion between large and small droplets, with a fixed global suspended fraction. Going beyond the assumptions of the classical theory of Farris (R.J. Farris, Trans. Soc. Rheol. 12, 281 (1968)), we discuss a shear viscosity minimum, as a function of the small-to-large-particle ratio, in shear geometries imposed by external body forces and boundaries. Within a linear-response scheme, we find the dependence of the viscosity minimum on the imposed shear and the microscopic drop friction parameters. We also discuss the viscosity minimum under dynamically imposed shear applied by boundaries. We find a reduction of macroscopic viscosity with the increase of the microscopic friction parameters that is understood using a simple two-drop model. Our simulation results are qualitatively consistent with recent experiments in concentrated bimodal emulsions with a highly viscous or rigid suspended component.