WITHDRAWN: Accuracy of Peak Treadmill Exercise Echocardiography to Detect Multivessel Coronary Artery Disease: Comparison with Post-exercise Echocardiography

The publisher regrets that this was an accidental duplication of an article that has already been published in Eur. J. Echocardiogr., 4 (2003) 182-190, . The duplicate article has therefore been withdrawn.

Structural Transformation of Au−Pd Bimetallic Nanoclusters on Thermal Heating and Cooling: A Dynamic Analysis

Classical molecular dynamics simulation is used for structural thermodynamic and dynamic analysis of Au-Pd bimetallic clusters. It is observed that the Pd-core/Au-shell structure is the most stable, and can be formed through annealing of other structures such as Au-core/Pd-shell, eutecticlike, or solid solution. Depending on the starting temperature and initial composition, three-layer icosahedral nanorod, face-centered cubic (fcc) nanorod, and fcc cluster can be obtained on slow cooling. The three-layer icosahedral nanorod structure is not as stable as the Pd-core/Au-shell decahedron; however it is more stable than the solid-solution decahedron structure up to 400 K. Our findings provide valuable insight into catalysis using Au-Pd and other similar bimetallic clusters.

Origin and phylogeography of the Chagas disease main vector Triatoma infestans based on nuclear rDNA sequences and genome size

For about half of all Chagas disease cases T. infestans has been the responsible vector. Contributing to its genetic knowledge will increase our understanding of the capacity of geographic expansion and domiciliation of triatomines. Populations of all infestans subcomplex species, T. infestans, T. delpontei, T. platensis and T. melanosoma and the so-called T. infestans "dark morph", from many South American countries were studied. A total of 10 and 7 different ITS-2 and ITS-1 haplotypes, respectively, were found. The total intraspecific ITS-2 nucleotide variability detected in T. infestans is the highest hitherto known in triatomines. ITS-1 minisatellites, detected for the first time in triatomines, proved to be homologous and thus become useful markers. Calculations show that ITS-1 evolves 1.12-2.60 times faster than ITS-2. Despite all species analyzed presenting the same n=22 chromosome number, a large variation of the haploid DNA content was found, including a strikingly high DNA content difference between Andean and non-Andean specimens of T. infestans (mean reduction of 30%, with a maximum of up to 40%) and a correlation between presence/absence of minisatellites and larger/smaller genome size. Population genetics analysis of the eight composite haplotypes of T. infestans and net differences corroborate that there are clear differences between western and eastern populations (60%), and little genetic variation among populations (1.3%) and within populations (40%) within these two groups with migration rates larger than one individual per generation corresponding only to pairs of populations one from each of these groups. These values are indicative either of a large enough gene flow to prevent population differentiation by drift within each geographic area or a very recent spread, the latter hypothesis fitting available data better. Phylogenetic trees support a common ancestor for T. infestans and T. platensis, an origin of T. infestans in Bolivian highlands and two different dispersal lines, one throughout Andean regions of Bolivia and Peru and another in non-Andean lowlands of Chile, Paraguay, Argentina, Uruguay and Brazil.

Therapeutic Cancer Vaccines: At Midway Between Immunology and Pharmacology

The pursuit of active specific immunotherapy of cancer re-emerged vigorously in the 90s. More than 50 vaccines are currently under clinical testing, and more than 400 clinical trials have been conducted. This wave of enthusiasm is rooted in fundamental immunology, as new paradigms, such as the dominant tolerance through T-regulatory cells and the instructive role of the innate immune system on the adaptive immune system, opened the possibility that an efficient cancer vaccination could be achieved even without the need of cancer neoantigens, provided that antigen presentation could be increased, and that regulatory circuits could be controlled. However, recent failures in some large trials have brought disappointment and have highlighted the differences between experiments in young, healthy mice with small transplanted tumours, and clinical testing in aged, ill patients with advanced spontaneous tumours, driving the attention to issues such as tumour editing, tumour-induced immunosuppression, and immunosenescence. The molecular basis of these phenomena is only partially known. Additionally, the inherent complexity of the immune system as a network of multiple interactions and redundant control loops among a huge diversity of components sets another barrier to the translation of in vitro reductionist knowledge into rationally designed clinical trials. All this calls for a new therapeutic paradigm in cancer vaccines, moving beyond the analogy with the classic drug-target approach, and targeting the immune system regulation as a whole, and its interaction with the tumour, in all its complexity. Early mathematical modelling of cancer immunotherapy has suggested how to go about it. This re-evaluation of the cancer vaccine landscape, suggests that future successful cancer immunotherapy will be combined immunotherapy, will be exquisitely schedule-dependent and will need new experimental models allowing for the exploration of the mechanisms of resistance and tumour escape, such as tumour editing and tumour induced immunosuppression, in the context of the physiology of the immune system of the elderly. These shifts will put cancer vaccines closer to pharmacology than to conventional preventive vaccinology, or at least at the midway. A change in the design and the ultimate goals of the clinical trials will also be needed, identifying long term stabilization of the disease and quality of life as main endpoints, again closer to the clinical management of most chronic noncommunicable diseases.

Recommendations for postmarketing surveillance studies in haemophilia and other bleeding disorders

Prospective surveillance studies to monitor drug safety in the postapproval period are rarely employed systematically, although they are of greatest value for caregivers, drug users and regulatory authorities. Safety issues have affected not only conventional pharmaceuticals, but also especially coagulation factors in haemophilia treatment. The reputation of postmarketing surveillance (PMS) studies has been questionable, mainly due to their misuse to solicit prescriptions. Other weaknesses include inappropriate design, lack of standardized observation, limited follow-up periods, absence of rigour in identifying potential adverse drug effects, and infrequent publication. Although well-designed clinical trials represent the gold standard for generating sound clinical evidence, a number of aspects would make PMS studies valuable, if properly conducted. One of their main advantages is broader inclusion, and absence of an 'experimental' design. Lack of proper guidelines, and standardization may constitute a reason for the generally low quality of PMS studies. This paper proposes guidelines for haemophilia-specific PMS studies, in order to improve the acceptance of a basically valuable tool. In the absence of consistent regulatory guidance it will be especially important that the design and supervision of PMS studies involves physicians from the beginning. This will not only make such studies more scientifically relevant, but also help to implement them into daily clinical practice. Specifically in haemophilia, PMS studies may provide valuable data on clinical outcomes, or Quality of Life, which is of great importance when considering adequate standards of care in haemophilia patients.

Structure, stability and catalytic activity of chemically synthesized Pt, Au, and Au-Pt nanoparticles

Small (1-5 nm) metallic nanoparticles of Pt, Au, and Au/Pt of different nominal compositions in colloidal form were synthesized by a chemical reduction method using polymer (PVP) as protecting agent. Analytical techniques like HREM and UV-vis spectroscopy have been used to characterize the morphology and structural properties of these small particles. Theoretical simulations based on molecular dynamical have been used to interpret the experimental structural results and analyze the macroscopic properties like stability and catalytic selectivity of these nanoparticles based on the morphology and atomic distribution in the clusters.

Retrosigmoid approach for vestibular neurectomy in Meniere's disease

BACKGROUND

Vestibular nerve section is considered to be the most effective surgical procedure to control intractable symptoms secondary to Meniere's disease (MD). This study was developed to analyze the adequacy of retrosigmoid vestibular neurectomy in terms of vertigo control, hearing preservation and clinical complications of this procedure.

METHODS

A retrospective review was carried out on 14 patients affected by definite unilateral MD who underwent vestibular neurectomy via the retrosigmoid approach.

FINDINGS

One patient was lost from follow-up; another one had only a short postoperative observation. At follow-up performed on 12 cases, no patients reported any crisis of acute vertigo. Four patients were free from any vestibular symptoms, while 8 reported some slight gait disturbances. Hearing function was preserved in 10 patients and improved in 2. 1 year postoperative vestibular function was absent at the side operated on and unchanged on the other side in all the cases.

CONCLUSIONS

Vestibular neurectomy via the retrosigmoid approach can be considered a safe and effective procedure in relieving medically refractory vertigo in Meniere's disease, while preserving hearing.

Mucin dynamics and microbial populations in chicken small intestine are changed by dietary probiotic and antibiotic growth promoter supplementation

The mucous layer that covers the intestinal absorptive surface acts as a barrier against bacterial translocation. The chicken gut contains a diverse bacterial population which interacts with the mucous layer. In this report, we studied the effect of changing the intestinal microbial populations on mucin dynamics by feeding 1-d-old chicks a control diet or that diet containing either antibiotic growth promoter (AGP) or a probiotic product for 14 d. Dietary AGP increased the proportions of Bifidobacterium species in the duodenum compared with the other groups. In AGP-fed chicks, the villous surface area was increased in the jejunum, goblet cell density was greater in the jejunum and ileum, and mucin glycoprotein levels in the duodenum were lower than in the other groups (P < 0.05). Feeding AGP increased the expression of mucin mRNA in the jejunum and ileum compared with controls. The dietary probiotic increased the proportion of Lactobacillus species in the ileum compared with the controls (P < 0.05) and significantly enlarged the goblet cell "cup" area throughout the small intestine compared with the other groups. Expression of mucin mRNA and the levels of mucin glycoprotein were greater in the jejunum of the probiotic-fed chicks compared with controls (P < 0.05). Neither the probiotic nor AGP treatments affected the thickness of the mucous adherent layer. These results indicate that both probiotic and AGP altered processes of mucin biosynthesis and/or degradation mediated via changes in the intestinal bacterial populations. These modifications in mucin dynamics influence gut function and health and may change nutrient uptake.

Accuracy of peak treadmill exercise echocardiography to detect multivessel coronary artery disease: comparison with post-exercise echocardiography

AIMS

Although peak exercise echocardiography has been reported for both bicycle and treadmill exercise and has shown higher sensitivity than post-exercise imaging, little is known about its utility for identifying multivessel involvement. We sought to compare feasibility and accuracy of peak treadmill exercise echocardiography vs post-exercise echocardiography for identification of multivessel coronary artery disease and to assess its incremental value when combined with clinical and exercise test variables.

METHODS AND RESULTS

The study group included 335 patients (228 men; mean (+/- SD) age 60 +/- 11 years). Two hundred and seventy-nine patients were included on the basis of having had an exercise echocardiography and a coronary angiography within 4 months of the exercise test. To avoid bias to coronary angiography, a subgroup of 56 consecutive non-diabetic patients referred for exercise echocardiography with pretest probability of coronary artery disease <10% and had atypical chest pain or were asymptomatic were also included and considered as having no coronary artery disease. Multivessel coronary artery disease (> or = 50% diameter stenosis in >1 vessel) was confirmed in 170 patients, whereas 165 patients were considered to have one-vessel coronary artery disease or no coronary lesions. Positive exercise echocardiography was defined as ischaemia or necrosis in at least two coronary territories. Post-exercise images were acquired within 125 s after exercise (49 +/- 15). Mean heart rate (bpm) was 139 +/- 19 at peak vs 117 +/- 22 at post-exercise imaging (P<0.001). Interpretable peak and post-exercise images were obtained for all patients. Sensitivity for predicting multivessel disease was higher with peak than with post-exercise imaging (79 vs 55%, P<0.001), with lower specificity (79 vs 88%, P<0.05). Predictive positive value was similar (80 vs 83%). Negative predictive value was again higher with peak imaging (78 vs 66%, P<0.01). Total accuracy was not different (79 vs 72%). A stepwise logistic regression analysis identified peak exercise echocardiography positivity for multivessel coronary artery disease as the strongest independent predictor of multivessel disease (odds ratio (OR): 7.36); also significant were male gender (OR: 4.22), diabetes mellitus (OR: 4.28), previous myocardial infarction (OR: 3.12) and increment of product heart rate x blood pressure (OR: 1.00).

CONCLUSIONS

Peak treadmill exercise echocardiography is technically feasible and has higher sensitivity and negative predictive value for predicting multivessel disease than post-treadmill exercise echocardiography. This method adds independent and incremental values to clinical and exercise variables for the diagnosis of multivessel coronary artery disease. Therefore, in the clinical setting, peak exercise echocardiography should be performed to diagnose multivessel coronary artery disease.

Epidermal growth factor-based cancer vaccine for non-small-cell lung cancer therapy

BACKGROUND

The role that growth factors and their receptors play in human cancer growth and progression makes them interesting targets for novel treatment modalities. Our approach consisted of active immunotherapy with the epidermal growth factor (EGF). Two pilot clinical trials were conducted to examine the safety and immunogenicity of a five-dose immunization protocol and to compare different adjuvants and treatment designs.

PATIENTS AND METHODS

Forty patients with advanced non-small-cell lung cancer were enrolled in both trials. They were randomized to be treated with aluminum hydroxide or montanide ISA 51 as adjuvants in the EGF vaccine preparation. The use of cyclophosphamide prevaccination treatment was evaluated in the second trial.

RESULTS

Pooled data from both trials showed that the use of montanide as adjuvant increased the percentage of good antibody responders (GAR). Cyclophosphamide prevaccination treatment did not provoke improvements in antibody response. GAR had a significant increase in survival as compared with poor antibody responders. Response duration was also related to a significant improvement in survival rates.

CONCLUSIONS

Vaccination with five doses of EGF vaccine is safe and immunogenic. Montanide ISA 51 increased the percentage of GAR. There is a direct relationship between anti-EGF antibody titers and immune response duration with survival time.

The neonate has a temporary conductive hearing loss due to fluid in the middle ear

Postnatal functional changes in the activity of the ear and auditory pathway in neonatal guinea pigs [from day of birth (postnatal day, PND = 0), PNDs 1-4, 7 and then weekly up to 7 weeks] were studied as a model of maturation of hearing in human neonates. On the day of birth there were signs of a conductive hearing loss: negative middle ear pressure, auditory nerve brainstem evoked response (ABR) threshold elevation, ABR wave 1 latency prolongation and low amplitude otoacoustic emissions. The conductive hearing loss is probably a result of the (amniotic) fluid found in the neonatal middle-ear cavity. Over the next PNDs, this conductive hearing loss was resolved. In order to confirm this neonatal conductive hearing loss and its resolution, saline was instilled into the middle ear of guinea pigs. This induced signs of a conductive hearing loss similar to those seen in the neonatal guinea pigs which disappeared with clearance of this fluid. Therefore it may be concluded that most of the changes in auditory function seen over the first PNDs are due to absorption of amniotic fluid from the middle-ear cavity.