Multiscale modeling of composite materials: a roadmap towards virtual testing

A bottom-up, multiscale modeling approach is presented to carry out high-fidelity virtual mechanical tests of composite materials and structures. The strategy begins with the in situ measurement of the matrix and interface mechanical properties at the nanometer-micrometer range to build up a ladder of the numerical simulations, which take into account the relevant deformation and failure mechanisms at different length scales relevant to individual plies, laminates and components. The main features of each simulation step and the information transferred between length scales are described in detail as well as the current limitations and the areas for further development. Finally, the roadmap for the extension of the current strategy to include functional properties and processing into the simulation scheme is delineated.

Occupational exposures and risk of stomach cancer by histological type

OBJECTIVE

To explore the relationship between stomach cancer (SC), by histological type, and occupations and occupational exposures.

METHODS

The authors conducted a hospital-based case-control study in south-east Spain. Subjects were 399 incident histological confirmed SC cases (241 intestinal and 109 diffuse adenocarcinomas) and 455 controls frequency matched by sex, age and province of residence. Occupation was coded according to the Spanish National Classification of Occupations 1994. Occupational exposures were assessed by the FINJEM Job Exposure Matrix. ORs were estimated by unconditional logistic regression adjusting for matching variables and education, smoking, alcohol and diet.

RESULTS

In men, statistically significant increased risk of the diffuse subtype was found for 'cooks' (OR 8.02), 'wood-processing-plant operators' (OR 8.13) and 'food and related products machine operators' (OR 5.40); for the intestinal subtype, a borderline association was found for 'miners and quarry workers' (OR men 4.22, 95% CI 0.80 to 22.14). Significant increased risk was observed between the diffuse subtype of SC and the highest level of exposure to 'pesticides' (OR(H) both sexes 10.39, 95% CI 2.51 to 43.02, p(trend)=0.02) and between the intestinal subtype and asbestos (OR(H) men 3.71, 95% CI 1.40 to 9.83, p(trend)=0.07). Restricted analyses of exposures of 15 years and longer showed significant associations between the diffuse subtype and the exposure to 'wood dust' (OR men 3.05).

CONCLUSIONS

This study supports the relationship previously suggested between SC and occupational exposure to dusty and high temperature environments. Several occupations may also increase the risk of diffuse SC but not the intestinal subtype.

Occupational exposures and risk of stomach cancer by histological type

OBJECTIVE

To explore the relationship between stomach cancer (SC), by histological type, and occupations and occupational exposures.

METHODS

The authors conducted a hospital-based case-control study in south-east Spain. Subjects were 399 incident histological confirmed SC cases (241 intestinal and 109 diffuse adenocarcinomas) and 455 controls frequency matched by sex, age and province of residence. Occupation was coded according to the Spanish National Classification of Occupations 1994. Occupational exposures were assessed by the FINJEM Job Exposure Matrix. ORs were estimated by unconditional logistic regression adjusting for matching variables and education, smoking, alcohol and diet.

RESULTS

In men, statistically significant increased risk of the diffuse subtype was found for 'cooks' (OR 8.02), 'wood-processing-plant operators' (OR 8.13) and 'food and related products machine operators' (OR 5.40); for the intestinal subtype, a borderline association was found for 'miners and quarry workers' (OR men 4.22, 95% CI 0.80 to 22.14). Significant increased risk was observed between the diffuse subtype of SC and the highest level of exposure to 'pesticides' (OR(H) both sexes 10.39, 95% CI 2.51 to 43.02, p(trend)=0.02) and between the intestinal subtype and asbestos (OR(H) men 3.71, 95% CI 1.40 to 9.83, p(trend)=0.07). Restricted analyses of exposures of 15 years and longer showed significant associations between the diffuse subtype and the exposure to 'wood dust' (OR men 3.05).

CONCLUSIONS

This study supports the relationship previously suggested between SC and occupational exposure to dusty and high temperature environments. Several occupations may also increase the risk of diffuse SC but not the intestinal subtype.

[Fucus vesiculosus induced hyperthyroidism in a patient undergoing concomitant treatment with lithium]

INTRODUCTION

Fucus vesiculosus is a marine alga rich in iodine, which is being used in alternative medicine as a laxative, diuretic, and as a complement for weight loss diets.

CASE REPORT

We report the case of a 60-year old male patient, diagnosed with bipolar disorder and under treatment with lithium concomitantly with a herbal preparation, including Fucus vesiculosus, as a laxative. He developed hyperthyroidism that remitted once the herbal preparation was withdrawn.

CONCLUSION

Fucus vesiculosus may cause hyperthyroidism given its high iodine content. Herbal preparations should be taken in account when treating a patient due to the possibility of adverse effects and interactions with other drugs.

Adherence to highly active antiretroviral therapy (HAART): a meta-analysis

This meta-analysis synthesizes eighty-four observational studies, conducted across twenty countries, to determine the mean proportion of people who reported ≥90% adherence to prescribed highly active antiretroviral therapy (HAART) and to identify the factors associated with high levels of adherence. Eight electronic databases were searched to locate all relevant studies available by January 2010, which were then coded for sample characteristics and adherence levels. The average rate of reporting ≥90% adherent HAART adherence is 62%. However, this proportion varies greatly across studies. In particular, a greater proportion of individuals maintaining ≥90% adherence to HAART is more likely in studies with higher proportions of men who have sex with men (MSM) and lower proportions of injection drug users (IDU), with participants in an earlier stage of infection, and in studies conducted in countries characterized by lower Human Development Index (HDI) scores.

Antimicrobial susceptibility of Helicobacter pylori to six antibiotics currently used in Spain

BACKGROUND

Antibiotic resistance is directly related to the loss of efficacy of currently accepted Helicobacter pylori therapies. Knowledge of the antibiotic susceptibility in a local area can contribute to the design of specific 'à la carte' treatments. The aim of this study was to analyse the susceptibility of H. pylori isolates to six conventional antibiotics currently used in a northern region of Spain.

METHODS

Seventy-one isolates were obtained from gastric biopsies of 76 consecutive adult patients suffering from peptic ulcer disease, dyspepsia or familial gastric cancer and known to be infected with H. pylori by conventional methods. Susceptibility testing was performed for amoxicillin, ciprofloxacin, levofloxacin, clarithromycin, metronidazole and tetracycline using the Etest method.

RESULTS

The prevalence rates of resistance were as follows: amoxicillin, 1.4% [95% confidence interval (CI) 0.0-7.6]; clarithromycin, 14.7% (95% CI 7.3-25.4); ciprofloxacin, 14.3% (95% CI 7.1-24.7); levofloxacin, 14.5% (95% CI 7.2-25.0); metronidazole, 45.1% (95% CI 33.2-57.3); and tetracycline, 0% (95% CI 0.0-5.1).

CONCLUSIONS

Our study confirms an increasing rate of resistance to levofloxacin that equals that of clarithromycin in our healthcare area. This fact may reflect a wide and indiscriminate use of the former antibiotic and could account for a loss of clinical effectiveness of levofloxacin-containing regimens. Moreover, clarithromycin resistance rates remain stable, which could allow us to maintain its use in our area.

Systemic lupus erythematosus in northwestern Spain: a 20-year epidemiologic study

To further investigate the epidemiology of systemic lupus erythematosus (SLE) in southern Europe, we assessed the incidence, prevalence, clinical spectrum of the disease, flares, and survival of patients diagnosed with SLE in the Lugo region of northwestern Spain. Between January 1987 and December 2006, 150 Lugo residents were diagnosed as having SLE according to the 1982 American College of Rheumatology criteria for the classification of SLE. Women outnumbered men (127 [84.7%] vs. 23 [15.3%]). The mean age at the time of disease diagnosis was 46.1 ± 19.6 years. The mean follow-up from the time of disease diagnosis was 7.8 ± 4.5 years. The age- and sex-adjusted annual incidence rate over the 20-year study period was 3.6 (95% confidence interval [CI], 3.0-4.2) per 100,000 population aged 15 years and older. The overall annual incidence rate over the 20-year study period in women (5.9/100,000 population aged ≥ 15 yr; 95% CI, 4.9-7.0) was higher than in men (1.1/100,000 population aged ≥ 15 yr; 95% CI, 0.7-1.7) (p < 0.001). By December 31, 2006, the overall age-adjusted SLE prevalence in the Lugo region for patients who fulfilled at least 4 of 1982 American College of Rheumatology criteria was 17.5 per 100,000 population aged 15 years and older (95% CI, 12.6-24.1). Prevalence in women (29.2/100,000 population aged ≥ 15 yr; 95% CI, 20.0-40.7) was higher than in men (5.8/100,000 population aged ≥ 15 yr; 95% CI, 2.0-12.0). The most frequent clinical manifestation was arthritis. As reported in population-based studies on SLE patients of European descent, renal disease was observed in only 27.3% of the patients. The rate of flares was 0.084/year. A younger age and the presence of nephritis at the time of disease diagnosis were associated with the development of flares during the follow-up of Lugo patients. Compared with the general population the probability of survival in patients with SLE was significantly reduced (p = 0.04). In conclusion, the present study establishes a baseline estimate of the incidence and clinical spectrum of SLE in northwestern Spain. According to our results, the incidence of SLE in northwestern Spain is slightly higher than that reported in most European regions. Patients with SLE from northwestern Spain have a later average age onset and a lower frequency of nephritis than in the African-American population. However, our data show a reduced probability of survival in Spanish patients with SLE.

CCR5Δ32 variant and cardiovascular disease in patients with rheumatoid arthritis: a cohort study

Introduction

The aim of our study was to analyze the influence of the CCR5Δ32 polymorphism in the risk of cardiovascular (CV) events and subclinical atherosclerosis among patients with rheumatoid arthritis (RA).

Methods

A total of 645 patients fulfilling the American Rheumatism Association 1987 revised classification criteria for RA were studied. Patients were genotyped for the CCR5 rs333 polymorphism using predesigned TaqMan assays. Also, HLA DRB1 genotyping was performed using molecular-based methods. Carotid intima-media thickness, flow-mediated endothelium-dependent dilatation (FMD) and endothelium-independent vasodilatation, which were used as surrogate markers of subclinical atherosclerosis, were measured in a subgroup of patients with no clinical CV disease.

Results

A lower frequency of carriers of the CCR5Δ32 allele among patients with CV events (3.4% versus 11.3%, P = 0.025, odds ratio 0.28, 95% confidence interval (95% CI) 0.06 to 0.89) was observed. However, after adjusting for gender, age at time of RA diagnosis, and the presence of shared epitope, rheumatoid factor and classic CV risk factors in the Cox regression analysis, this reduction of CV events in CCR5Δ32 allele carriers was slightly outside the range of significance (P = 0.097; hazard ratio 0.37 (95% CI 0.12 to 1.19)). Carriers of the CCR5Δ32 deletion also showed higher FMD values than the remaining patients (CCR5/CCR5Δ32 patients: 7.03% ± 6.61% versus CCR5/CCR5 patients: 5.51% ± 4.66%). This difference was statistically significant when analysis of covariance was performed (P = 0.024).

Conclusions

Our results show a potential influence of the CCR5Δ32 deletion on the risk of CV disease among patients with RA. This may be due to a protective effect of this allelic variant against the development of vascular endothelial dysfunction.

[Utility of the dead space fraction (Vd/Vt) as a predictor of extubation success]

PURPOSE

To determine the value of Vd/Vt as a predictor of extubation failure in patients with mechanical ventilation admitted to the intensive care units.

DESIGN

A prospective, observational cohort study conducted from 1 September 2010 to 1 March 2011.

SETTING

General intensive care unit (G-ICU) of a third level university hospital.

PATIENTS OR PARTICIPANTS

The study included patients on mechanical ventilation (MV) for over 12 hours, and who in the process of weaning were subjected to low-level pressure support. Exclusion criteria were age under 18 years, ventilation via tracheotomy and patients failing to cooperate for different reasons. During the study, 392 patients were admitted to the G-ICU; of these, 214 required MV. The weaning process was started in 154 cases. Fifty-four patients were excluded from the study, and 24 were not extubated from MV. A total of 76 patients were finally extubated and analyzed.

VARIABLES OF INTEREST

Vd/Vt was calculated as the ratio (PaCO(2)-Pє CO(2))/PaCO(2), with the recorded parameters.

RESULTS

Logistic regression analysis showed a significant association between the Vd/Vt and extubation failure, with OR=1.52 (95%CI 1.11 to 2.09, p=0.008). The area under the ROC curve with respect to the prediction of extubation failure according to the Vd/Vt value was 0.94 (95%CI 0.86 to 0.98, p<0.0001).

CONCLUSIONS

Vd/Vt is a powerful predictor of extubation failure in patients on MV.

Association of acid phosphatase locus 1*C allele with the risk of cardiovascular events in rheumatoid arthritis patients

Introduction

Acid phosphatase locus 1 (ACP1) encodes a low molecular weight phosphotyrosine phosphatase implicated in a number of different biological functions in the cell. The aim of this study was to determine the contribution of ACP1 polymorphisms to susceptibility to rheumatoid arthritis (RA), as well as the potential contribution of these polymorphisms to the increased risk of cardiovascular disease (CV) observed in RA patients.

Methods

A set of 1,603 Spanish RA patients and 1,877 healthy controls were included in the study. Information related to the presence/absence of CV events was obtained from 1,284 of these participants. All individuals were genotyped for four ACP1 single-nucleotide polymorphisms (SNPs), rs10167992, rs11553742, rs7576247, and rs3828329, using a predesigned TaqMan SNP genotyping assay. Classical ACP1 alleles (*A, *B and *C) were imputed with SNP data.

Results

No association between ACP1 gene polymorphisms and susceptibility to RA was observed. However, when RA patients were stratified according to the presence or absence of CV events, an association between rs11553742*T and CV events was found (P = 0.012, odds ratio (OR) = 2.62 (1.24 to 5.53)). Likewise, the ACP1*C allele showed evidence of association with CV events in patients with RA (P = 0.024, OR = 2.43).

Conclusions

Our data show that the ACP1*C allele influences the risk of CV events in patients with RA.

Lack of association of NAMPT rs9770242 and rs59744560 polymorphisms with disease susceptibility and cardiovascular risk in patients with rheumatoid arthritis

OBJECTIVES

Visfatin is an adipokine encoded by the NAMPT (PBEF1) gene. In this study we assessed the potential association of two NAMPT gene polymorphisms with disease susceptibility and cardiovascular (CV) risk in patients with rheumatoid arthritis (RA).

METHODS

A total of 1,395 patients fulfilling the 1987 ACR classification criteria for RA and 1,230 matched controls, were genotyped for the NAMPT rs9770242 and rs59744560 gene polymorphisms, located within the proximal promoter, using predesigned TaqMan single nucleotide polymorphism genotyping assay. Also, HLA-DRB1 genotyping was performed using molecular based methods. In a second step, 1,196 patients in whom full information was available were assessed to determine the influence of NAMPT rs9770242 and rs59744560 polymorphisms in the development of CV events. Also, the potential influence of these polymorphisms in the development of subclinical atherosclerosis was assessed in a subgroup of patients with no history of CV events by brachial artery reactivity to determine flow-mediated endothelium-dependent and endothelium-independent vasodilatation (n=125) and by B-mode ultrasonography to determine the carotid artery intima-media thickness (n=105).

RESULTS

No statistically significant differences in the allele or genotype frequencies for the NAMPT gene polymorphisms between RA patients and controls were found. A modest non significant lower frequency of the minor allele G of rs9770242 polymorphism was observed among patients with CV disease (20.62%) compared to those without CV disease (22.83%) (p=0.39). Also, a slight nonsignificant lower frequency of the minor allele T of rs59744560 polymorphism in patients with CV events (9.81%) compared with those RA patients who did not experience CV disease (13.07%) (p=0.11) was observed. Likewise, no significant association between the NAMPT polymorphisms with surrogate markers of subclinical atherosclerosis was found in patients with RA.

CONCLUSIONS

NAMPT rs9770242 and rs59744560 polymorphisms are not markers of disease susceptibility and CV disease in RA.

Correlation between endothelial function and carotid atherosclerosis in rheumatoid arthritis patients with long-standing disease

Introduction

In this study, we aimed to determine the relationship between flow-mediated endothelium-dependent vasodilatation (FMD) and carotid artery intima-media wall thickness (IMT), two surrogate markers of atherosclerosis, in a series of Spanish patients with rheumatoid arthritis (RA) without clinically evident cardiovascular (CV) disease.

Methods

One hundred eighteen patients who fulfilled the 1987 American College of Rheumatology classification criteria for RA, had no history of CV disease and had at least one year of follow-up after disease diagnosis were randomly selected. Brachial and carotid ultrasonography were performed to determine FMD and carotid IMT, respectively.

Results

Carotid IMT values were higher and FMD percentages derived by performing ultrasonography were lower in individuals with a long duration from the time of disease diagnosis. Patients with a disease duration ≤ 7 years had significantly lower carotid IMT (mean ± SD) 0.69 ± 0.17 mm than those with long disease duration (0.81 ± 0.12 mm in patients with ≥ 20 years of follow-up). Also, patients with a long disease duration had severe endothelial dysfunction (FMD 4.0 ± 4.0% in patients with disease duration from 14.5 to 19.7 years) compared with those with shorter disease duration (FMD 7.4 ± 3.8% in patients with disease duration ≤ 7 years). Linear regression analysis revealed that carotid IMT was unrelated to FMD in the whole sample of 118 patients. However, carotid IMT was negatively associated with FMD when the time from disease diagnosis ranged from 7.5 to 19.7 years (P = 0.02).

Conclusions

In patients with RA without CV disease, endothelial dysfunction and carotid IMT increased with the duration of RA. The association between FMD and carotid IMT values was observed only in patients with long disease duration.

Assessment of cardiovascular risk in rheumatoid arthritis: impact of the new EULAR recommendations on the score cardiovascular risk index

To assess the impact of the application of the European League against Rheumatism (EULAR) task force recommendations in the cardiovascular (CV) risk of a series of Spanish patients diagnosed with rheumatoid arthritis (RA). Two hundred consecutive RA patients seen at the rheumatology outpatient clinics of Bellvitge Hospital, Barcelona, were studied. Information on clinical features of the disease, classic CV risk factors, and history of CV events was assessed. Both the systematic coronary risk evaluation (SCORE) CV risk index and the modified SCORE (mSCORE) according to the last EULAR recommendations were calculated. Based on the classic CV risk factors, the mean ± standard deviation SCORE was 2.1 ± 2.3% (median, 2; interquartile range [IQR], 1-3). Twenty-three (11%) patients were above the threshold of high CV risk for the Spanish population (≥5%). Following the EULAR recommendations, a change in the score was required in 119 (59%) patients. Therefore, the mean mSCORE was 2.7 ± 2.9% (median, 2; IQR, 1-3) and, due to this, 28 (14%) patients were above the threshold of high CV risk. Nine (5%) had at least one ischemic CV event. Patients with CV events were older and had more CV risk factors and higher SCORE and mSCORE than those without CV events. Although a large proportion of patients from this series fulfilled the criteria for the application of the EULAR recommendations, the final impact on the calculated CV risk was low and clinically significant in only a few patients. However, an association between the mSCORE and the presence of ischemic CV events was observed.

Relapses and recurrences in giant cell arteritis: a population-based study of patients with biopsy-proven disease from northwestern Spain

We conducted the present study to determine the incidence of disease flares (relapses and recurrences) in a series of patients with biopsy-proven giant cell arteritis (GCA). We assessed a series of 174 patients who were diagnosed with biopsy-proven GCA, uniformly treated, and followed at the rheumatology division of Hospital Xeral-Calde (Lugo, Spain), the single rheumatology division for a well-defined population. All of them were followed for at least 1 year after the disease diagnosis. Seventy-one (40.8%) experienced relapses or recurrences of the disease. Patients who had relapses or recurrences did not show clinical differences when compared with the remaining biopsy-proven GCA patients. However, the total duration of corticosteroid therapy was significantly longer in those patients who had relapses or recurrences of the disease. The median dose of prednisone and the median duration of corticosteroid treatment at the time of the first relapse were 5 mg/d and 16 months, respectively. Headache (52%) was the most common feature at the time of the first relapse. Polymyalgia rheumatica manifestations occurred in 30% of the patients at that time. However, none of them developed visual loss. Thirty-two patients experienced recurrences of the disease when prednisone dose had been discontinued. The median time from the disease diagnosis to the time of the recurrence was 23 months. The presence of anemia (hemoglobin <12 g/dL) at the time of disease diagnosis was the best predictor of relapses or recurrences of GCA (odds ratio, 2.17; 95% confidence interval, 1.02-4.62; p = 0.04). The results from the present study confirm that relapses and recurrences are frequent in homogenously treated patients with biopsy-proven GCA. A chronic inflammatory response manifested by anemia at the time of disease diagnosis may predict the development of disease flares.

MYC in chronic myeloid leukemia: induction of aberrant DNA synthesis and association with poor response to imatinib

Untreated chronic myeloid leukemia (CML) progresses from chronic phase to blastic crisis (BC). Increased genomic instability, deregulated proliferation, and loss of differentiation appear associated to BC, but the molecular alterations underlying the progression of CML are poorly characterized. MYC oncogene is frequently deregulated in human cancer, often associated with tumor progression. Genomic instability and induction of aberrant DNA replication are described as effects of MYC. In this report, we studied MYC activities in CML cell lines with conditional MYC expression with and without exposure to imatinib, the front-line drug in CML therapy. In cells with conditional MYC expression, MYC did not rescue the proliferation arrest mediated by imatinib but provoked aberrant DNA synthesis and accumulation of cells with 4C content. We studied MYC mRNA expression in 66 CML patients at different phases of the disease, and we found that MYC expression was higher in CML patients at diagnosis than control bone marrows or in patients responding to imatinib. Further, high MYC levels at diagnosis correlated with a poor response to imatinib. MYC expression did not directly correlate with BCR-ABL levels in patients treated with imatinib. Overall our study suggests that, as in other tumor models, MYC-induced aberrant DNA synthesis in CML cells is consistent with MYC overexpression in untreated CML patients and nonresponding patients and supports a role for MYC in CML progression, possibly through promotion of genomic instability.

Audiovestibular manifestations in patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease of unknown origin affecting up to 1% of the population. Little is known about audiovestibular impairment in patients with AS, especially the presence of cochleovestibular dysfunction in these patients. To investigate audiovestibular manifestations in AS, we studied a series of 50 consecutive patients who fulfilled the modified New York diagnostic criteria for AS and 44 matched controls. Individuals with history of cardiovascular disease, cerebrovascular complications, peripheral artery disease, renal insufficiency, syphilis, Meniere and other vestibular syndromes, infections involving the inner ear, barotrauma, or in treatment with ototoxic drugs were excluded. Most patients with AS were men (80%). The mean age at the time of study was 52.5 years, and mean age at the onset of symptoms was 34.4 years. Twenty-nine (58%) patients showed abnormal hearing loss in the audiogram compared to only 8 (18%) controls (p < 0.001). Values of audiometric tests (pure-tone average and speech reception threshold) yielded significant differences between patients and controls (p < 0.001). It is noteworthy that the audiogram shape disclosed a predominant pattern of high-frequency sensorineural hearing loss in AS patients (50%) compared to controls (18%) (p = 0.002). Also, AS patients exhibited abnormal vestibular tests more commonly than controls. AS patients had an increased frequency of head-shaking nystagmus (20%) compared to controls (0%) (p < 0.001). Moreover, patients (26%) showed a significantly increased frequency of abnormal caloric test compared to controls (0%) (p < 0.001). Finally, a significantly increased frequency of abnormal clinical test of sensory integration and balance with a predominant vestibular loss pattern was observed in patients (36%) compared to controls (5%) (p < 0.001). In conclusion, the current study demonstrates strong evidence for inner ear compromise in patients with AS.