Alzheimer's amyloid β heterogeneous species differentially affect brain endothelial cell viability, blood-brain barrier integrity, and angiogenesis

Impaired clearance in the Alzheimer's Disease (AD) brain is key in the formation of Aβ parenchymal plaques and cerebrovascular deposits known as cerebral amyloid angiopathy (CAA), present in >80% of AD patients and ~50% of non-AD elderly subjects. Aβ deposits are highly heterogeneous, containing multiple fragments mostly derived from catabolism of Aβ40/Aβ42, which exhibit dissimilar aggregation properties. Remarkably, the role of these physiologically relevant Aβ species in cerebrovascular injury and their impact in vascular pathology is unknown. We sought to understand how heterogeneous Aβ species affect cerebral endothelial health and assess whether their diverse effects are associated with the peptides aggregation propensities. We analyzed cerebral microvascular endothelial cell (CMEC) viability, blood-brain barrier (BBB) permeability, and angiogenesis, all relevant aspects of brain microvascular dysfunction. We found that Aβ peptides and fragments exerted differential effects on cerebrovascular pathology. Peptides forming mostly oligomeric structures induced CMEC apoptosis, whereas fibrillar aggregates increased BBB permeability without apoptotic effects. Interestingly, all Aβ species tested inhibited angiogenesis in vitro. These data link the biological effects of the heterogeneous Aβ peptides to their primary structure and aggregation, strongly suggesting that the composition of amyloid deposits influences clinical aspects of the AD vascular pathology. As the presence of predominant oligomeric structures in proximity of the vessel walls may lead to CMEC death and induction of microhemorrhages, fibrillar amyloid is likely responsible for increased BBB permeability and associated neurovascular dysfunction. These results have the potential to unveil more specific therapeutic targets and clarify the multifactorial nature of AD.

Lactating dairy cows managed for second and greater artificial insemination services with the Short-Resynch or Day 25 Resynch program had similar reproductive performance

The objective of this randomized controlled experiment was to evaluate reproductive performance and reproductive physiological outcomes of lactating Holstein cows managed for second and greater artificial insemination (AI) services with the Short-Resynch or Day 25 Resynch program. Cows from 2 commercial farms were randomly assigned after first service to the Short-Resynch (SR; n = 870) or Day 25 Resynch (D25R; n = 917) program in which they remained until 210 d after first service or left the herd. Cows in D25R received GnRH 25 ± 3 d after AI, whereas cows in SR did not. Cows not reinseminated at detected estrus (AIE) by 32 ± 3 d after AI underwent nonpregnancy diagnosis (NPD) through transrectal ultrasonography (TUS). Nonpregnant cows from both treatments with a corpus luteum (CL) ≥15 mm and an ovarian follicle ≥10 mm (hereafter, CL cows) received 2 PGF_2α treatments 24 h apart, GnRH 32 h after the second PGF_2α, and timed AI 16 to 18 h later. Cows that did not meet the criteria to be included in the CL group (NoCL cows) received a modified Ovsynch protocol with progesterone (P4) supplementation [P4-Ovsynch; GnRH and controlled internal drug-release device (CIDR) in, 7 d later CIDR removal and PGF_2α, 24 h later PGF_2α, 32 h later GnRH, and 16 to 18 h later timed AI]. In a subgroup of cows, blood samples were collected and TUS conducted at each treatment to evaluate ovarian responses to resynchronization. Binary data were analyzed with logistic regression, continuous data by ANOVA, and time-to-event data by Cox's proportional hazard regression. A greater proportion (mean; 95% CI) of cows were AIE before NPD in the SR (60.5%; 57.0-63.8; n = 3,416) than the D25R (50.1%; 46.5-53.7; n = 3,177) treatment, whereas pregnancy per AI (P/AI) at 32 d for AIE services before NPD was greater for the D25R (41.3%; 38.8-43.8; n = 1,560) than the SR (37.6%; 35.5-39.8; n = 1,961) treatment. At NPD, a greater proportion of cows in the D25R (84.3%; 82.2-86.2) than the SR (77.0%; 74.4-79.4) treatment were considered CL cows. Pregnancy per AI at 32 d was greater for the D25R than the SR treatment for all timed AI services (D25R = 43.0%; 40.2-45.9 vs. SR = 36.8%; 33.8-39.8) and for CL cows (D25R = 42.8%; 39.7-45.9 vs. SR = 33.8%; 30.6-37.2) but did not differ for NoCL cows (D25R = 39.4%; 32.1-47.3 vs. SR = 44.0%; 36.8-51.4). The hazard ratio for time to pregnancy (1.03; 0.93-1.14) and the proportion of cows not pregnant at the end of the observation period (D25R = 5.9%; 4.4-7.8 vs. SR = 6.7%; 5.0-8.7) did not differ between SR and D25R treatments. The GnRH treatment 25 d after AI resulted in more cows with P4 >1 ng/mL (D25R = 80.5%; 75.3-84.9 vs. SR = 63.6%; 57.3-69.4) and smaller follicle diameter at NPD 32 ± 3 d after AI for D25R (16.2 ± 0.4 mm) than for SR (17.5 ± 0.4 mm); however, it did not affect follicle diameter and luteal regression risk (CL cows only) before TAI. We concluded that the use of reproductive management programs including SR and D25R for CL cows and the P4-Ovsynch protocol for NoCL cows resulted in similar hazard of pregnancy and proportion of nonpregnant cows for up to 210 d after first service.

Correction: DUB3 and USP7 de-ubiquitinating enzymes control replication inhibitor Geminin: molecular characterization and associations with breast cancer

The final sentence of the Acknowledgements should be as follows: This work was supported by grants from Instituto de Salud Carlos III (BA15/00092), Spanish Ministry of Economy and Competitiveness/EU-ERDF (SAF2016-80626-R, SAF2013-49149-R, BFU2014-51672-REDC), Fundación CajaCanarias (AP2015/008) to RF, and the Australian National Health and Medical Research (NHMRC program grant to SRL and KKK (APP1017028).

First assessment of persistent organic pollutant contamination in blubber of Chilean blue whales from Isla de Chiloé, southern Chile

Persistent organic pollutants (POPs) were assessed for the first time in blue whales from the South Pacific Ocean. Concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB) and dichlorodiphenyltrichloroethane and its main metabolites (DDTs), were determined in 40 blubber samples from 36 free-ranging individuals and one stranded, dead animal along the coast of southern Chile between 2011 and 2013. PCBs were the most abundant pollutants (2.97-975 ng/g l.w.), followed by DDTs (3.50-537 ng/g l.w.), HCB (nd-77.5 ng/g l.w.) and PBDEs (nd-33.4 ng/g l.w). There was evidence of differences between sexes, with lower loads in females potentially due to pollutants passing to calves. POP concentrations were higher in specimens sampled in 2013; yet, between-year differences were only statistically significant for HCB and PBDEs. Lower chlorinated (penta > tetra > tri) and brominated (tetra > tri) congeners were the most prevalent among PCBs and PBDEs, respectively, mostly in agreement with findings previously reported in blue and other baleen whales. The present study provides evidence of lower levels of contamination by POPs in eastern South Pacific blue whales in comparison to those reported for the Northern Hemisphere.

DUB3 and USP7 de-ubiquitinating enzymes control replication inhibitor Geminin: molecular characterization and associations with breast cancer

This corrects the article DOI: 10.1038/onc.2017.21.

DUB3 and USP7 de-ubiquitinating enzymes control replication inhibitor Geminin: molecular characterization and associations with breast cancer

Correct control of DNA replication is crucial to maintain genomic stability in dividing cells. Inappropriate re-licensing of replicated origins is associated with chromosomal instability (CIN), a hallmark of cancer progression that at the same time provides potential opportunities for therapeutic intervention. Geminin is a critical inhibitor of the DNA replication licensing factor Cdt1. To properly achieve its functions, Geminin levels are tightly regulated through the cell cycle by ubiquitin-dependent proteasomal degradation, but the de-ubiquitinating enzymes (DUBs) involved had not been identified. Here we report that DUB3 and USP7 control human Geminin. Overexpression of either DUB3 or USP7 increases Geminin levels through reduced ubiquitination. Conversely, depletion of DUB3 or USP7 reduces Geminin levels, and DUB3 knockdown increases re-replication events, analogous to the effect of Geminin depletion. In exploring potential clinical implications, we found that USP7 and Geminin are strongly correlated in a cohort of invasive breast cancers (P<1.01E-08). As expected, Geminin expression is highly prognostic. Interestingly, we found a non-monotonic relationship between USP7 and breast cancer-specific survival, with both very low or high levels of USP7 associated with poor outcome, independent of estrogen receptor status. Altogether, our data identify DUB3 and USP7 as factors that regulate DNA replication by controlling Geminin protein stability, and suggest that USP7 may be involved in Geminin dysregulation during breast cancer progression.

Improving the mix of institutional and community care for older people with dementia: an application of the balance of care approach in eight European countries

OBJECTIVES

To examine whether the mix of community and institutional long-term care (ILTC) for people with dementia (PwD) in Europe could be improved; assess the economic consequences of providing alternative services for particular groups of ILTC entrants and explore the transnational application of the 'Balance of Care' (BoC) approach.

METHOD

A BoC study was undertaken in Estonia, Finland, France, Germany, the Netherlands, Spain, Sweden, and the UK as part of the RightTimePlaceCare project. Drawing on information about 2014 PwD on the margins of ILTC admission, this strategic planning framework identified people whose needs could be met in more than one setting, and compared the relative costs of the possible alternatives.

RESULTS

The findings suggest a noteworthy minority of ILTC entrants could be more appropriately supported in the community if enhanced services were available. This would not necessarily require innovative services, but more standard care (including personal and day care), assuming quality was ensured. Potential cost savings were identified in all countries, but community care was not always cheaper than ILTC and the ability to release resources varied between nations.

CONCLUSIONS

This is believed to be the first transnational application of the BoC approach, and demonstrates its potential to provide a consistent approach to planning across different health and social care systems. Better comparative information is needed on the number of ILTC entrants with dementia, unit costs and outcomes. Nevertheless, the findings offer important evidence on the appropriateness of current provision, and the opportunity to learn from different countries' experience.

Polymerization Shrinkage Influences Microtensile Bond Strength

Shrinkage results from a complex spatial strain network, producing movements within materials. The purpose of this study was to test whether microtensile bond strength (μTBS) of a light-curing resin composite to enamel depends on distance to the center of the curing mass. Labial surfaces of bovine incisors were ground flat, divided into 2 groups (n = 8), acid-etched, and coated with an unfilled resin bond. A resin-based composite was placed in one increment (group A) or separately at gingival, central, and incisal sites (group B), and light-cured. Teeth were sectioned, yielding stick-shaped specimens assigned to one of 9 groups according to distance to incisal edge of restoration (NDistanc). Microtensile bond strength was transformed to percentages of its maximum values within each tooth (PMPa). Comparisons within groups showed (group A) that mean PMPa decreased from central to gingival and from central to incisal (p < 0.01). Comparisons between groups showed that mean PMPa was significantly lower in group A compared with group B, only at gingival and incisal sites. Microtensile bond strength significantly decreased as the distance increased to the center of the curing mass.

RNF168 cooperates with RNF8 to mediate FOXM1 ubiquitination and degradation in breast cancer epirubicin treatment

The forkhead box M1 (FOXM1) transcription factor has a central role in genotoxic agent response in breast cancer. FOXM1 is regulated at the post-translational level upon DNA damage, but the key mechanism involved remained enigmatic. RNF168 is a ubiquitination E3-ligase involved in DNA damage response. Western blot and gene promoter-reporter analyses showed that the expression level and transcriptional activity of FOXM1 reduced upon RNF168 overexpression and increased with RNF168 depletion by siRNA, suggesting that RNF168 negatively regulates FOXM1 expression. Co-immunoprecipitation studies in MCF-7 cells revealed that RNF168 interacted with FOXM1 and that upon epirubicin treatment FOXM1 downregulation was associated with an increase in RNF168 binding and conjugation to the protein degradation-associated K48-linked polyubiquitin chains. Consistently, RNF168 overexpression resulted in an increase in turnover of FOXM1 in MCF-7 cells treated with the protein synthesis inhibitor cycloheximide. Conversely, RNF168, knockdown significantly enhanced the half-life of FOXM1 in both absence and presence of epirubicin. Using a SUMOylation-defective FOXM1-5x(K>R) mutant, we demonstrated that SUMOylation is required for the recruitment of RNF168 to mediate FOXM1 degradation. In addition, clonogenic assays also showed that RNF168 mediates epirubicin action through targeting FOXM1, as RNF168 could synergise with epirubicin to repress clonal formation in wild-type but not in FOXM1-deficient mouse embryo fibroblasts (MEFs). The physiological relevance of RNF168-mediated FOXM1 repression is further emphasized by the significant inverse correlation between FOXM1 and RNF168 expression in breast cancer patient samples. Moreover, we also obtained evidence that RNF8 recruits RNF168 to FOXM1 upon epirubicin treatment and cooperates with RNF168 to catalyse FOXM1 ubiquitination and degradation. Collectively, these data suggest that RNF168 cooperates with RNF8 to mediate the ubiquitination and degradation of SUMOylated FOXM1 in breast cancer genotoxic response.

The carbonic anhydrase inhibitor methazolamide prevents amyloid beta-induced mitochondrial dysfunction and caspase activation protecting neuronal and glial cells in vitro and in the mouse brain

Mitochondrial dysfunction has been recognized as an early event in Alzheimer's disease (AD) pathology, preceding and inducing neurodegeneration and memory loss. The presence of cytochrome c (CytC) released from the mitochondria into the cytoplasm is often detected after acute or chronic neurodegenerative insults, including AD. The carbonic anhydrase inhibitor (CAI) methazolamide (MTZ) was identified among a library of drugs as an inhibitor of CytC release and proved to be neuroprotective in Huntington's disease and stroke models. Here, using neuronal and glial cell cultures, in addition to an acute model of amyloid beta (Aβ) toxicity, which replicates by intra-hippocampal injection the consequences of interstitial and cellular accumulation of Aβ, we analyzed the effects of MTZ on neuronal and glial degeneration induced by the Alzheimer's amyloid. MTZ prevented DNA fragmentation, CytC release and activation of caspase 9 and caspase 3 induced by Aβ in neuronal and glial cells in culture through the inhibition of mitochondrial hydrogen peroxide production. Moreover, intraperitoneal administration of MTZ prevented neurodegeneration induced by intra-hippocampal Aβ injection in the mouse brain and was effective at reducing caspase 3 activation in neurons and microglia in the area surrounding the injection site. Our results, delineating the molecular mechanism of action of MTZ against Aβ-mediated mitochondrial dysfunction and caspase activation, and demonstrating its efficiency in a model of acute amyloid-mediated toxicity, provide the first combined in vitro and in vivo evidence supporting the potential of a new therapy employing FDA-approved CAIs in AD.

Clinical practice models in nursing education: implication for students' mobility

BACKGROUND

In accordance with the process of nursing globalization, issues related to the increasing national and international mobility of student and qualified nurses are currently being debated. Identifying international differences and comparing similarities for mutual understanding, development and better harmonization of clinical training of undergraduate nursing students is recommended.

AIMS

The aim of the study was to describe and compare the nature of the nursing clinical practice education models adopted in different countries.

METHODS

A qualitative approach involving an expert panel of nurses was adopted. The Nominal Group Technique was employed to develop the initial research instrument for data collection. Eleven members of the UDINE-C network, representing institutions engaged in the process of professional nursing education and research (universities, high schools and clinical institutes), participated. Three data collection rounds were implemented. An analysis of the findings was performed, assuring rigour.

RESULTS

Differences and homogeneity are reported and discussed regarding: (a) the clinical learning requirements across countries; (b) the prerequisites and clinical learning process patterns; and (c) the progress and final evaluation of the competencies achieved.

CONCLUSIONS

A wider discussion is needed regarding nursing student exchange and internalization of clinical education in placements across European and non-European countries. A clear strategy for nursing education accreditation and harmonization of patterns of organization of clinical training at placements, as well as strategies of student assessment during this training, are recommended. There is also a need to develop international ethical guidelines for undergraduate nursing students gaining international experience.

Two-Year Clinical Performance of a Low-Shrinkage Composite in Posterior Restorations

Objectives

The aim of this study was to compare the two-year clinical performance of three restorative systems in posterior restorations, which included a low-shrinkage composite and both etch-and-rinse and self-etch adhesive strategies.

Materials and Methods

After signing an informed consent, 25 patients received three Class I (occlusal) or Class II restorations performed with one of three restorative systems: Filtek Silorane Restorative System, Adper Scotchbond 1 XT (a two-step etch-and-rinse adhesive) with Filtek Z250, and Adper Scotchbond SE (a two-step self-etch adhesive) with Filtek Z250. All materials were applied following the manufacturer's instructions. Two blind observers evaluated the restorations at three different moments (baseline; and after one and two years) according to the US Public Health Service modified criteria. Kruskal-Wallis test and Mann-Whitney U-test were used to compare the behavior of the restorative systems, while Friedman and Wilcoxon tests were applied to analyze the intra-system data (p&lt;0.05).

Results

The three restorative systems showed a statistically similar clinical performance at two years. Intra-system comparisons between baseline and two years showed declining marginal adaptation scores in the restorations placed with all systems. In addition, marginal staining and surface roughness scores were lower after two years for the restorations placed with Adper Scotchbond SE + Filtek Z250.

Conclusions

Although the clinical performance of Filtek Silorane was considered acceptable after two years, no advantage of the silorane-based resin over the methacrylate-based composite was found. Teeth restored with Adper Scotchbond SE showed a tendency for marginal staining, which may compromise the final color of the restorations.

Injection Molding of Water Containing Thermoplastic Polyolefin

In this paper, we present a novel injection molding approach using water containing thermoplastic polyolefin (TPO) to reduce the cycle time and to improve the dimensional stability of parts without any equipment or mold modifications. A small amount of water was pressurized into TPO pellets pre-mixed with water carrier particles such as highly porous activated carbon or tubular-shaped nanoclay. Our results showed that the cycle time could be drastically reduced with substantially reduced surface sink mark and part warpage without any adverse effects on mechanical properties. Water evaporation during molding resulted in internal cooling, which led to a large reduction in cycle time. This phenomenon, however, could not be explained by the average water content in TPO alone. It is believed that the accumulation of water in the thickest section of the mold cavity, i.e., the base of the conical shaped sprue in the molds used in the study, during injection molding played a major role. The lower sink mark and part warpage were due to water induced internal cooling and foaming. Complete filling of thin parts could also be achieved at a lower packing pressure in the presence of water, perhaps due to steam (from water evaporation) induced mold cavity heating during filling. This was supported by the measured temperature rise at the mold surface in the early stage of the molding cycle.

Clinical Evaluation of a Low-shrinkage Composite in Posterior Restorations: One-Year Results

Objectives

The aim of this study was to compare the one-year clinical performance of three restorative systems, which included a novel low-shrinkage composite and two bonding strategies.

Materials and Methods

Twenty-five patients received three Class I (occlusal) or Class II restorations performed with one of three restorative systems: Filtek Silorane Restorative System (FS); Adper Scotchbond 1 XT, a two-step etch-and-rinse adhesive, with Filtek Z250 (XT); and Adper Scotchbond SE, a two-step self-etch adhesive, with Filtek Z250 (SE). All materials were applied following the manufacturer's instructions. Two independent observers evaluated the restorations at baseline, after six months, and after one year, according to the United States Public Health System modified criteria. The Kruskal-Wallis test and the Mann-Whitney U-test were computed to compare the behavior of the restorative systems; Friedman and Wilcoxon tests were used to analyze the intrasystem data (α=0.05).

Results

All restorations were evaluated at one year. FS and XT performed statistically similarly at one year, but marginal staining for SE was statistically worse. Intrasystem comparisons between baseline and one year also showed deterioration of marginal staining for SE, while a deterioration of the marginal adaptation was recorded for both SE and FS. XT was the only system for which there was no statistical change of the parameters measured in this study.

Conclusions

Both restorative systems using self-etch adhesives showed a tendency to degradation of marginal adaptation after one year of clinical use, compared to baseline values. Although the clinical performance of FS was deemed acceptable after one year, this study did not find any advantage of the silorane-based composite over the methacrylate-based composite. The low-shrinkage associated with FS may not be a determinant factor for clinical success.

Nine steps towards a better water meter management

The paper provides a comprehensive perspective of the critical aspects to be taken into account when planning the long-term management of water meters in a utility. In order to facilitate their quick understanding and practical implementation, they have been structured into nine steps. Ranging from an initial audit up to the final periodic meter replacement planning, these steps cover three aspects of the problem - field work, laboratory work and management tasks; and each one is developed in detail paying attention to the particular data needed and noting the practical outcome it will yield.

A methodology for the selection of a routine purity test for insoluble beta(1-->3)glucan

Beta(1-->3)glucan isolated from the cell wall of Saccharomyces cerevisiae is a biological response modifier (BRM) stimulating resistance against bacterial, viral, fungal and protozoal diseases. This polysaccharide has a high molecular weight, which makes it very difficult to achieve a purity test. A comparative study of different analytical procedures for beta(1-->3)glucan from S. cerevisiae was conducted in order to establish a reliable routine analytical methodology for quality control of this active ingredient in pharmaceutical products. With this aim, different combinations of the analytical procedure steps were tested, including three alternatives for the acid hydrolysis step, three for neutralization, two for gas-liquid chromatographic derivatization and two internal standards. The glucose yield, precision, time consumption and reagent cost per sample were determined for 10 sample replicates. All gas chromatographic determinations were conducted using packed GLC columns and an FID detector. The selected analytical method showed 83.61 +/- 3.48% glucose yield, the shortest relative time consumption (54.2%) and the lowest cost of reagents (7.4%) and consisted of a combination of 72% sulfuric acid hydrolysis, 25% ammonium hydroxide neutralization and alditol acetate derivatization using xylose as internal standard.

Diels-Alder cycloaddition approach to puupehenone-related metabolites: synthesis of the potent angiogenesis inhibitor 8-epipuupehedione

A new synthetic strategy toward puupehenone-related bioactive metabolites from sclareol oxide, based on a Diels-Alder cycloaddition approach, is described. Utilizing this, marine ent-chromazonarol and the potent angiogenesis inhibitor 8-epipuupehedione have been synthesized.

[Analysis of the Educational Program for Self-Care in the Elderly (PECA) for improving the quality of life of the elderly]

OBJECTIVE

To determine the efficacy over 12 months of the educational programme on self-care of the elderly (PECA), which covers quality of life, nutritional status, and perceived social support of people over 65 living in their own homes.

DESIGN

Pre-test/post-test experimental study with control group.

SETTING

Urban population in the Manso Health District (Example, Barcelona), Spain.

PARTICIPANTS

Persons over 65 living in their own homes, healthy or with chronic illnesses characteristic of their age, who had a normal score in the Pfeiffer test. A total of 70 subjects (35 per group) were selected and 5 of the control group left the study.

INTERVENTION

Programme on self-care of the elderly, including education on physical activity, nutrition, and social support.

MEASUREMENTS

Dependent variables were quality of life, measured by the Nottingham Health Profile; nutritional status, measured by the Mini-Nutritional Assessment (MNA); and social support, measured by the Duke-Unk Functional Social Support Scale.

RESULTS

The study sample had an average age of 70.9 (SD, 3.1); 88.2% had self-perception of good health; and 21% lived alone. We only found statistically significant differences between pre- and post-intervention observations in nutritional status (P=.001).

CONCLUSION

Despite a statistically significant difference in the variable of nutritional status, the difference was not "clinically" relevant. The ineffectiveness of the intervention is due to our starting from a very homogeneous sample, which had good health status and well-established social networks.

First enantiospecific synthesis of the antitumor marine sponge metabolite (-)-15-oxopuupehenol from (-)-sclareol

[reaction: see text] A new route toward puupehenone-related bioactive metabolites from (-)-sclareol, based on the palladium(II)-mediated diastereoselective cyclization of a drimenylphenol, is described. Utilizing this, the first enantiospecific synthesis of the antitumor and antimalarial (-)-15-oxopuupehenol, together with improved syntheses of (+)-puupehenone, (+)-puupehedione, and (+)-15-cyanopuupehenone, were accomplished.

[Vascular access for haemodyalisis. Comparative analysis of the mechanical behaviour of native vessels and prosthesis]

INTRODUCTION

The prosthesis nowadays used in the vascular access for haemodialysis have low patency rates, mainly due to the luminal obstruction, determined by the intimal hyperplasia. Several factors have been related to de development of intimal hyperplasia and graft failure. Among them are the differences in the biomechanical properties between the prosthesis and the native vessels. In the searching for vascular prosthesis that overcomes the limitations of the currently used, the cryopreserved vessels (cryografts) appear as an alternative of growing interest. However, it is unknown if the mechanical differences or mismatch between prosthesis and native vessels are lesser when using cryografts.

OBJECTIVE

To characterize and compare the biomechanical behaviour of native vessels used in vascular access and cryografts. Additionally, segments of expanded polytetrafluoroethylene (ePTFE) were also evaluated, so as to evaluate the potential biomechanical advantages of the cryografts respect to synthetic prosthesis used in vascular access.

METHODS

Segments from human humeral (n = 12), carotid (n = 12) and femoral (n = 12) arteries, and saphenous vein (n = 12), were obtained from 6 multiorgan donors. The humeral arteries were studied in fresh state. The other segments were divided into two groups, and 6 segments from each vessel were studied in fresh state, while the remaining 6 segments were evaluated after 30 days of criopreservation. For the mechanical evaluation the vascular segments and 6 segments of ePTFE were mounted in a circulation mock and submitted to haemodynamic conditions similar to those of the in vivo. Instantaneous pressure (Konigsberg) and diameter (Sonomicrometry) were measured and used to calculate the viscous and elastic indexes, the compliance, distensibility and characteristic impedance. For each mechanical parameter studied, the mismatch between the prosthesis and the native vessel was evaluated.

RESULTS

The ePTFE was the prosthesis with the higher mechanical mismatch (p < 0.05). The venous and arterial cryografts showed the least mismatch with native veins and arteries, respectively. The prosthesis with the least mechanical mismatch was different, depending on the native vessel evaluated, and for a native vessel, on the parameter considered.

CONCLUSION

The mechanical mismatch between the native vessel and the vascular prosthesis used in a vascular access could be reduced using cryografts.

Biodiversity of uptake hydrogenase systems from legume endosymbiotic bacteria

Uptake hydrogenases in legume endosymbiotic bacteria recycle hydrogen produced during the nitrogen fixation process in legume nodules. Despite the described beneficial effect on plant productivity, the hydrogen oxidation capability is not widespread in the Rhizobiaceae family. Characterization of hydrogenase gene clusters in strains belonging to Rhizobium, Bradyrhizobium and Azorhizobium reveals a similar overall genetic organization along with important differences in gene regulation. In addition, phylogenetic analysis of hup genes indicates distinct evolutionary origins for hydrogenase genes in Rhizobia.

[The non Q wave myocardial infarction in conventional valvular surgery. Diagnosis with cardiac troponin I]

INTRODUCTION

Morbidity and mortality in elective valve surgery is still significant. The main cause of death in these patients is cardiogenic shock, of which the most frequent etiology is acute myocardial infarction (AMI) with Q wave in the ECG. However, there are patients with cardiogenic shock without Q wave in the ECG and with rises in CK-MB enzyme that makes us suspect non-Q wave AMI.

OBJECTIVE

To analyze the use of the determination of cardiac troponin-I, a more specific marker of AMI than CK-MB after cardiac surgery, to detect perioperative non-Q wave AMI, and to establish its clinical significance.

METHODS

A total of 147 patients without coronary artery disease scheduled for elective valve surgery were included. We used, based in anterior publications, ECG (presence or not of new Q wave) and cardiac troponin I to define perioperative AMI. Levels of cardiac troponin-I were analysed before surgery and 14 hours after. Non-Q wave AMI was diagnosed when troponin I was superior to 38.85 ng/ml and there was not a phatologic Q wave in ECG.

RESULTS

One hundred twenty-three (83.67%) of patients did not have AMI, 9 (6.12%) suffered perioperative AMI with Q wave, and 15 (10.27%) carried out criteria of non-Q wave perioperative AMI. Morbidity and mortality in this last group was similar to that in the group with Q wave AMI. Morbidity and mortality were minimum in patients without AMI.

CONCLUSIONS

This study suggest the possibility of in vivo identification of non-Q wave perioperative AMI, an entity with important morbidity and mortality in our series, with a simple determination of cardiac troponin I 14 hours after surgery.

[Gemcitabine in the treatment of 4 patients with cholangiocarcinoma]

Cholangiocarcinoma is a biliary tree cancer of unknown etiology, whose symptoms are unspecific and is usually detected in advanced stages. Surgery continues to be the only curative therapy. Median survival in patients with inoperable tumors ranges between 5 and 8 months. There are few studies on the effects of chemotherapy, with a very small response. We report four patients with advanced cholangiocarcinoma, treated with gemcitabine 1000 mg/m2, weekly for 3 weeks every 28 days. There was a stabilization of tumor size and symptoms were alleviated. Toxicity was low and there was a probable prolongation of survival.

[Effect of anti-inflammatory drugs, alone and combined with ofloxacin, on the respiratory burst of human polymorphonuclear leukocytes]

The antibacterial activity of polymorphonuclear leukocytes (PMNs) is based on the production of superoxide anion and H(2)O(2) in the respiratory burst and can be impaired in different ways. The combination of an antibacterial agent and an antiinflammatory drug is quite common in immunodepressed patients whose respiratory burst of PMN could be impaired. In this study we examine in vitro the effect of pretreating (35 degrees C for 30 min) PMNs with the antiinflammatory drugs dexamethasone (0.4, 4 and 40 microgram/ml), methylprednisolone (0.37, 3.7 and 37 microgram/ ml), hydrocortisone (0.048, 0.48 and 4.8 microgram/ml), betamethasone (0.1, 1, 5 and 10 mg/ml), phenylbutazone (1000 microgram/ml) and acetylsalicylic acid (25, 250, 2500 microgram/ml) alone, and combined with 10 mg/ml of ofloxacin on the respiratory burst. Superoxide anion was measured by the cytochrome c reduction microtechnique and H(2)O(2) by phenol red. The antiinflammatory drugs alone decreased the production of H(2)O(2) (except dexamethasone and methylprednisolone) and superoxide anion (except betamethasone) from 15-45%, depending on the antiinflammatory drug and concentration, while ofloxacin increased the production of superoxide anion (20.2 +/- 6.7%). The combination of antiinflammatory drugs with ofloxacin neutralizes the inhibitory effect of the former on the respiratory burst of PMNs. It is therefore important to know the effect of drugs on the respiratory burst in order to choose those that have the same therapeutic effect without interfering with PMN functions.

The role of CNSs in promoting elderly patients' autonomy in long-term institutions: problems and implications for nursing practice and research

Autonomy has become an important focus within healthcare. Elderly patients, however, are often denied the right to independent decision making on grounds of incompetence and incapacity. In long-term institutions there are several ways in which the clinical nurse specialist can promote the autonomy of elderly patients. This article provides an overview of the concept of autonomy and discusses some of the problems in its realization in long-term nursing institutions. It also outlines strategies for supporting autonomy in elderly patients and concludes with a discussion of the implications of autonomy to nursing practice and research.

Natural and synthetic podolactones with potential use as natural herbicide models

A collection of 11 natural and synthetic podolactones have been tested as allelochemicals in a range between 10(-4) and 10(-9) M, and their potential use as natural herbicide models is discussed. Their effects on the germination and growth of the dicots Lactuca sativa (cv. Nigra and cv. Roman), Lepidium sativum, and Lycopersicon esculentum and the monocots Allium cepa, Hordeum vulgare, and Triticum aestivum as standard target species have been studied. An important inhibitory effect on the germination and growth of all tested species (average = 90%) was produced by compounds 9-11 at 10(-4) M. The specific structural requirements related to their activities are studied. On the basis of these results, their use as potential natural herbicide models is proposed.

ESR and optical absorption studies of gamma- and electron-irradiated sugar crystals

Electron spin resonance (ESR) studies of the free radicals induced in gamma- or electron-irradiated sugar crystals were performed. The number of radicals increases linearly, pointing out that this material can be used as a dosimeter. The optical absorption studies show the presence of several distinctive bands in the infrared and UV region, whose intensity changes with the irradiation dose. An interpretation of these results in terms of the formation of free radicals and possible crosslinking along the sugar molecular chains is presented.

[Subcutaneous heparin during the first trimesters of pregnancy in women with prosthetic heart valves]

BACKGROUND

Oral anticoagulation therapy in pregnant women with prosthetic heart valves is associated with a greater risk of abortion, fetal malformations and thromboembolic complications.

AIM

To assess the use of subcutaneous heparin in women with pregnancies of less than 12 weeks as an alternative to oral anticoagulation therapy.

MATERIAL AND METHODS

Pregnant women were admitted to the hospital and coumarinics were replaced with not fractionated subcutaneous heparin in a dose of 10,000 IU every 12 hours, aiming at prolonging partial thromboplastin time, 2 or 2 1/2 times. During the hospitalization period, women were taught about the heparin injection technique. Coumarinics were restarted after week 13 of pregnancy until 10 days prior to the delivery date in which women were again admitted to the hospital and intravenous heparin was used until the delivery.

RESULTS

Between 1991 and 1997, this protocol was used during ten pregnancies in seven women aged 19 to 36 years old. Five had a Starr-Edwards prosthesis, one had a mitral Björk-Shilley prosthesis and one, a double prosthesis (mitral Starr-Machi and aortic St Jude). Subcutaneous heparin was started in the fifth week of pregnancy in 1 case, in the sixth week in seven and in the seventh week in two. There was no maternal mortality and one transient ischemic attack without sequelae. One non compliant patient had a Björk Shilley prosthetic valve dysfunction that required a valve replacement at the twelfth week of pregnancy and she had a spontaneous abortion at week 15. Other patient had a pneumonia at week 37 and gave birth to a stillbirth. There were no fetal malformations.

CONCLUSIONS

This therapeutic protocol can be used among Chilean patients, but must be restricted to compliant women and a strict surveillance must be maintained.

Synthesis of 11,12-epoxydrim-8,12-en-11-ol, 11,12-diacetoxydrimane, and warburganal from (-)-sclareol

The first syntheses are reported for recently isolated drimanes 11, 12-epoxydrim-8,12-en-11-ol (2) and 11,12-diacetoxydrimane (3), from (-)-sclareol (1). Furthermore, two efficient new routes to the potent bioactive warburganal (4) starting also from 1 are described.

Killing of gram-negative bacteria by ciprofloxacin within both healthy human neutrophils and neutrophils with inactivated O2-dependent bactericidal mechanisms

The intraphagocytic killing of Escherichia coli, Serratia marcescens, Pseudomonas aeruginosa, and Salmonella typhi by ciprofloxacin (0.1, 1 and 5 microg/ml) within human neutrophils with intact and impaired (by phenylbutazone treatment) O2-dependent killing mechanisms was studied and compared with the extracellular killing in the same medium of the intraphagocytic killing, but omitting neutrophils. The MIC/MBC of ciprofloxacin in vitro (assays performed according to NCCLS specifications) were: 0.015/0.06 for E. coli, 0.12/32 for S. marcescens, 1/16 for P. aeruginosa, and 0.007/0.06 for S. typhi. Ciprofloxacin showed bactericidal activity both extracellular and within phenylbutazone-treated and untreated neutrophils. The minimum concentration of ciprofloxacin to kill 90% of phagocytosed bacteria within neutrophils with normal O2-dependent killing power after 30 min was: 0.1 microg/ml for E. coli, and S. typhi, 1 microg/ml for P. aeruginosa, and 5 microg/ml for S. marcescens. In contrast, exposure for 60 min was required to reach this percentage within phenylbutazone treated neutrophils. The minimum concentration to kill 90% of extracellular bacteria after 30 min was: 0.1 microg/ml for E. coli, P. aeruginosa and S. typhi, and 5 microg/ml, for S. marcescens. A positive interaction between ciprofloxacin and the O2-dependent mechanisms of phagocytes was found. The reactive oxygen metabolites produced in the respiratory burst did not affect the intraphagocytic activity of ciprofloxacin. Phenylbutazone treatment of phagocytes would be a good experimental model to study the intraphagocytic killing of drugs in situations such as AIDS and chronic granulomatous disease where inefficient oxidative mechanisms of neutrophils exist.

[Effect of antiinflammatory agents on the accumulation of ofloxacin in human polymorphonuclear leukocytes]

The uptake of quinolones is a recently defined pharmacokinetic parameter which is increasing in importance in clinical practice, especially for immunocompromised patients whose polymorphonuclear leukocytes (PMNLs) have their bactericidal systems impaired, or in infections due to bacteria able to survive in the phagocytes. In both situations, antibiotics able to penetrate and be active in the phagocytes are required. The simultaneous administration of an antibiotic and an antiinflammatory drug is frequent, and previous studies have described interactions between the intracellular activity of the quinolones and the presence of phenylbutazone. We studied the effect of the presence of and the pretreatment (37 C for 30 and 60 min) of human PMNLs with the antiinflammatory drugs betamethasone (1 mg/l), hydrocortisone (1 mg/l), phenylbutazone (10 mg/ml), and acetylsalicylic acid (200 mg/l) on the uptake of ofloxacin (10 mg/l) by the PMNLs using a fluorometric method to measure the intra-PMNL concentration of ofloxacin. The presence of betamethasone did not modify the uptake of ofloxacin by PMNLs. Pretreatment of PMNLs with hydrocortisone, phenylbutazone and acetylsalicylic acid produced a significant decrease in the maximum intracellular concentration/extracellular concentration ratios compared with the maximum reached without pretreatment. These results suggest that hydrocortisone, phenylbutazone and acetylsalicylic acid interfere with the uptake of ofloxacin by PMNLs and increase the efflux of ofloxacin from PMNLs.

[Effect of fluconazole and itraconazole on human polymorphonuclear leukocyte oxidative metabolism and phagocytosis]

The effect of pretreatment of human polymorphonuclear leukocites (PMNs), for 30 min with fluconazole (0.1, 1, 5 and 50 microgram/ml) and itraconazole (0.05, 0.5 and 5 microgram/ml) on phagocytosis and generation of free radicals (superoxide anion and hydrogen peroxide) was studied in vitro. Phorbol miristate acetate (200 nM) was used as a stimulant. The mean amount of superoxide anion generated by 2.5 x 10(5) PMNs per hour was 4.39 +/- 1.13 nmol for fluconazole-treated PMNs and 4.56 +/- 1.2 nmol for itraconazole, and that of hydrogen peroxide was 11.19 +/- 2.18 and 11.28 +/- 3.61 nmol, respectively. The phagocytosis percentages were 83.8% for the control group and 88. 7% in antifungal agent- treated PMNs; the phagocytosis index was 3.0 yeasts per PMN for both groups. The differences between the control and treated PMNs were not statistically significant at any of the tested concentrations.

Characterization of transgenic tilapia lines with different ectopic expression of tilapia growth hormone

The transfer of growth hormone (GH) genes has opened new possibilities for the manipulation of growth in economically important fish species. However, the ectopic GH levels to optimize growth acceleration in fish, and specially in tilapia, are not known and must be determined experimentally. The tilapia GH (tiGH) cDNA was used to construct chimeric genes expressing different levels of tiGH in vitro and in vivo. These constructs were used to generate four lines of transgenic tilapia by microinjection into one-cell embryos. Different patterns and levels of ectopic expression of tiGH and IGF were detected in organs of transgenic tilapia by RNA or protein analysis. The two lines with lower ectopic tiGH mRNA levels were the only ones showing growth acceleration, suggesting that the expression of ectopic tiGH promoted growth only at low expression levels. The effect of higher ectopic tiGH levels resembled the physiologic situation of low condition factor and permitted us to postulate a model for growth acceleration in transgenic tilapia expressing ectopic tiGH.

Hydrogenase genes from Rhizobium leguminosarum bv. viciae are controlled by the nitrogen fixation regulatory protein nifA

Rhizobium leguminosarum bv. viciae expresses an uptake hydrogenase in symbiosis with peas (Pisum sativum) but, unlike all other characterized hydrogen-oxidizing bacteria, cannot express it in free-living conditions. The hydrogenase-specific transcriptional activator gene hoxA described in other species was shown to have been inactivated in R. leguminosarum by accumulation of frameshift and deletion mutations. Symbiotic transcription of hydrogenase structural genes hupSL originates from a -24/-12 type promoter (hupSp). A regulatory region located in the -173 to -88 region was essential for promoter activity in R. leguminosarum. Activation of hupSp was observed in Klebsiella pneumoniae and Escherichia coli cells expressing the K. pneumoniae nitrogen fixation regulator NifA, and in E. coli cells expressing R. meliloti NifA. This activation required direct interaction of NifA with the essential -173 to -88 regulatory region. However, no sequences resembling known NifA-binding sites were found in or around this region. NifA-dependent activation was also observed in R. etli bean bacteroids. NifA-dependent hupSp activity in heterologous hosts was also absolutely dependent on the RpoN sigma-factor and on integration host factor. Proteins immunologically related to integration host factor were identified in R. leguminosarum. The data suggest that hupSp is structurally and functionally similar to nitrogen fixation promoters. The requirement to coordinate nitrogenase-dependent H2 production and H2 oxidation in nodules might be the reason for the loss of HoxA in R. leguminosarum and the concomitant NifA control of hup gene expression. This evolutionary acquired control would ensure regulated synthesis of uptake hydrogenase in the most common H2-rich environment for rhizobia, the legume nodule.

[Acute myeloid leukemia MO: clinical and laboratory characteristics]

BACKGROUND

A recent update of FAB classification has included a myeloid leukemia subtype with a minimal degree of differentiation, that has been denominated LMA-MO.

AIM

To report the clinical, morphological and immunophenotypic features of patients with LMA-MO.

PATIENTS AND METHODS

Eight patients, out of 368, with acute myeloid leukemia that were studied in the Hematology Laboratory of a public hospital in Santiago, were classified as LMA-MO.

RESULTS

Blast cell morphology was undifferentiated or of subtype FAB-L2 lymphoblastic leukemia with medium sized blasts, agranular basophilic cytoplasm, reticular nuclear chromatin and a prominent nucleolus. Cytochemical staining was negative for peroxidase and esterases, immunophenotyping showed the expression of one or more myeloid antigens (CD13, CD33) and was negative for lymphoid antigens. Immunocytochemical expression of myeloperoxidase was positive in the three cases where it was performed. Only one patient achieved complete remission and is free of disease after 36 months of follow up. All other patients died without obtaining remission, six shortly after the onset and one 12 months after.

CONCLUSIONS

The diagnosis of LMA-MO is essential considering its dismal prognosis.