Atomic force microscopy and scanning electron microscopy analysis of daily disposable limbal ring contact lenses

BACKGROUND

Limbal ring (also known as 'circle') contact lenses are becoming increasingly popular, especially in Asian markets because of their eye-enhancing effects. The pigment particles that give the eye-enhancing effects of these lenses can be found on the front or back surface of the contact lens or 'enclosed' within the lens matrix. The purpose of this research was to evaluate the pigment location and surface roughness of seven types of 'circle' contact lenses.

METHODS

Scanning electron microscopic (SEM) analysis was performed using a variable pressure Hitachi S3400N instrument to discern the placement of lens pigments. Atomic force microscopy (Dimension Icon AFM from Bruker Nano) was used to determine the surface roughness of the pigmented regions of the contact lenses. Atomic force microscopic analysis was performed in fluid phase under contact mode using a Sharp Nitride Lever probe (SNL-10) with a spring constant of 0.06 N/m. Root mean square (RMS) roughness values were analysed using a generalised linear mixed model with a log-normal distribution. Least square means and their corresponding 95% confidence intervals were estimated for each brand, location and pigment combination.

RESULTS

SEM cross-sectional images at 500× and 2,000× magnification showed pigment on the surface of six of the seven lens types tested. The mean depth of pigment for 1-DAY ACUVUE DEFINE (1DAD) lenses was 8.1 μm below the surface of the lens, while the remaining lens types tested had pigment particles on the front or back surface. Results of the atomic force microscopic analysis indicated that 1DAD lenses had significantly lower root mean square roughness values in the pigmented area of the lens than the other lens types tested.

CONCLUSIONS

SEM and AFM analysis revealed pigment on the surface of the lens for all types tested with the exception of 1DAD. Further research is required to determine if the difference in pigment location influences on-eye performance.

Manual therapy, exercise therapy, or both, in addition to usual care, for osteoarthritis of the hip or knee. 2: economic evaluation alongside a randomized controlled trial

OBJECTIVE

To evaluate the cost effectiveness of manual physiotherapy, exercise physiotherapy, and a combination of these therapies for patients with osteoarthritis of the hip or knee.

METHODS

206 Adults who met the American College of Rheumatology criteria for hip or knee osteoarthritis were included in an economic evaluation from the perspectives of the New Zealand health system and society alongside a randomized controlled trial. Resource use was collected using the Osteoarthritis Costs and Consequences Questionnaire. Quality-adjusted life years (QALYs) were calculated using the Short Form 6D. Willingness-to-pay threshold values were based on one to three times New Zealand's gross domestic product (GDP) per capita of NZ$ 29,149 (in 2009).

RESULTS

All three treatment programmes resulted in incremental QALY gains relative to usual care. From the perspective of the New Zealand health system, exercise therapy was the only treatment to result in an incremental cost utility ratio under one time GDP per capita at NZ$ 26,400 (-$34,081 to $103,899). From the societal perspective manual therapy was cost saving relative to usual care for most scenarios studied. Exercise therapy resulted in incremental cost utility ratios regarded as cost effective but was not cost saving. For most scenarios combined therapy was not as cost effective as the two therapies alone.

CONCLUSIONS

In this study, exercise therapy and manual therapy were more cost effective than usual care at policy relevant values of willingness-to-pay from both the perspective of the health system and society. Trial registration number Australian New Zealand Clinical Trials Registry ACTRN12608000130369.

Genetic polymorphisms and cervical cancer development: ATM G5557A and p53bp1 C1236G

Persistent infections by high-risk types of human papillomavirus (HPV) have been established as the etiological agent of cervical cancer. The integration of the HPV genome into the host genome is a crucial step in cervical carcinogenesis, although, correct activation of DNA damage repair pathways will avoid the development of cancer. Recent data indicate that several polymorphisms of key regulators from the DNA damage repair pathway (i.e. 53BP1 and ATM) are associated with cancer development susceptibility. We have developed a hospital-based retrospective study considering 429 cervical specimens from women with different cervical lesions including invasive carcinoma. This study aimed to evaluate the role of the ATM D1853N (5557G>A) and 53bp1 D353E (1236C>G) polymorphisms in the development of cervical cancer, using TaqMan SNP Genotyping Assays. Statistical analysis revealed that ATM 5557GG homozygous individuals (OR=1.94; p=0.044) are at increased risk of developing LSIL, while for the 53BP1 1236C>G polymorphism no association was found. Nevertheless, we observed a tendency for an increased risk of LSIL in 53BP1 1236C allele carriers (OR=1.63; p=0.069). Logistic regression adjusted for age revealed no significant differences from the non-adjusted analysis. This is the first study to evaluate the role of ATM G5557A and P53BP1 C1236G polymorphisms in cervical cancer susceptibility. This study reveals a possible trend of both polymorphisms for a genetic susceptibility pattern of cervical cancer development. Hence, our results may be of interest for future understanding of the progression of cervical cancer.

[Prevalence and determinants of atypical presentation of acute coronary syndrome]

INTRODUCTION

Knowledge of the characteristics of patients with atypical presentation of acute coronary syndromes may contribute to increased sensitivity in diagnosis in a given population. The purpose of this study is to quantify the prevalence of atypical presentation, to identify its determinants, and to describe the presenting symptoms in cases of acute coronary syndrome at the emergency department of Hospital São João, Porto.

POPULATION AND METHODS

Systematic sample of 288 emergency admissions with a confirmed diagnosis of acute coronary syndrome in 2007. Atypical presentation was defined as absence of chest pain and/or syncope.

RESULTS

The prevalence of atypical presentation was 20.5% [95% confidence interval (CI): 16.0 to 25.5], with no important variation by gender. It increased with age and was more frequent in cases of ST-segment elevation myocardial infarction. In multivariate analysis, atypical presentation was associated with age [>70 versus ≤ 50 years, odds ratio (OR)=3.45; 95%CI: 1.03-11.61] and it was about four times less likely in the presence of history of ischemic heart disease, hypertension, dyslipidemia and smoking. A history of heart failure was independently associated with a higher likelihood of acute coronary syndrome with atypical presentation (OR = 4.15, 95%CI 1.50-11.46). Among the 223 cases who had chest pain or discomfort, a growing, oppressive, prolonged (longer than 30 minutes), recurrent and episodic pain prevailed. Among other symptoms, dyspnea was the most frequently reported, either as the main symptom in cases of atypical presentation or concurrently with typical symptoms.

DISCUSSION

Factors associated with atypical presentation are consistent with those described in other populations. Using routine clinical data allowed access to a large data base on a representative sample of patients admitted to the emergency department of a third-level hospital that serves a large part of the local urban population. In medical records, data are unstandardized and heterogeneous in validity and detail.

CONCLUSIONS

One fifth of the episodes of acute coronary syndrome have atypical presentation, and this proportion is higher in older ages. Previous history of ischemic heart disease or its classical risk factors are associated with typical symptoms, while heart failure is associated with atypical presentation. Presentation in atypical cases is highly variable and does not allow the identification of a pattern that would justify lowering the threshold for suspicion of acute coronary syndrome.

Hemizygous deletions on chromosome 1p21.3 involving the DPYD gene in individuals with autism spectrum disorder

We describe the identification and clinical presentation of four individuals from three unrelated families with hemizygous deletions involving the DPYD gene at chromosome 1p21.3. DPYD encodes dihydropyrimidine dehydrogenase, which is the initial and rate-limiting enzyme in the catabolism of pyrimidine bases. All four individuals described met diagnostic criteria for autism spectrum disorder with severe speech delay. Patient 1's deletion was originally reported in 2008, and more detailed clinical information is provided. Subsequently, this male individual was found to have a missense mutation in the X-linked PTCHD1 autism susceptibility gene, which may also contribute to the phenotype. Patients 2 and 3 are siblings with a novel deletion encompassing the DPYD gene. In their mother, the genomic region deleted from chromosome 1p21.3 was inserted into chromosome 10. A fourth proband had a novel 10-kb intragenic deletion of exon 6 of the DPYD gene detected on a higher resolution microarray. Our study suggests that hemizygous deletions involving the DPYD locus present with variable phenotypes which can include speech delay and autistic features, and may also be influenced by additional mutations in other genes, issues which need to be considered in genetic counseling.

Sensitivity and specificity of the Manchester Triage System for patients with acute coronary syndrome

INTRODUCTION

Monitoring the performance of triage systems is essential to optimize their usefulness in each hospital. The objective of this study was to assess the sensitivity of the Manchester Triage System in assigning high priority to patients with acute coronary syndrome, and the sensitivity and specificity of the combinations of flowcharts and discriminators routinely used for triage in the Emergency Department of Hospital de S. João, Porto.

METHODS

We analyzed a systematic sample of one third of emergency department episodes in 2007, corresponding to 53,039 episodes, of which 307 were cases of acute coronary syndrome. For each episode, we considered the final diagnosis by the Emergency Department attending physician, which was confirmed in 95% of cases. The combinations of flowchart and discriminators suggestive of acute coronary syndrome were defined, based on typical symptoms, including precordial chest pain with or without radiation and/or syncope.

RESULTS

The sensitivity of the Manchester Triage System in assigning high priority (immediate--red, or very urgent--orange) to patients with acute coronary syndrome was 87.3% (95% confidence interval [CI]: 83.1-90.6). The proportion of false negatives was higher in extreme age-groups. The sensitivity of combinations of flowchart and discriminators suggestive of acute coronary syndrome was 74.3% (95% CI: 69.1-78.8), lower in women (67.3% vs. 77.7%), and the specificity was 97.4% (95% CI: 97.2-97.5). The likelihood ratio of combinations of flowchart and discriminators suggestive of acute coronary syndrome was 28.3 (95% CI: 26.0-30.8) and that of other combinations was 0.26 (95% CI: 0.22-0.32), less informative in ruling out acute coronary syndrome in women (0.33 vs. 0.23).

DISCUSSION

The main limitations of this study derive from the impossibility of including only patients who came directly to this Emergency Department and of testing the validity of the final diagnosis when acute coronary syndrome was not identified in the Emergency Department. However, using electronic data records completed as a matter of routine enabled analysis of a large database, which reflects the practical value of the Manchester Triage System in this context, and most cases identified as acute coronary syndrome were confirmed.

CONCLUSIONS

The Manchester Triage System has a high sensitivity in assigning high priority (immediate/very urgent) to patients with acute coronary syndrome. The combinations of flowchart and discriminators defined as suggestive of acute coronary syndrome have very high specificity and moderate sensitivity, but the system has the potential to become more sensitive with no loss in specificity.