Quantitative reflection spectroscopy at the human ocular fundus

A new model of the reflection of the human ocular fundus on the basis of the adding-doubling method, an approximate solution of the radiative transport equation, is described. This model enables the calculation of the concentrations of xanthophyll in the retina, of melanin in the retinal pigment epithelium and the choroid, and of haemoglobin in the choroid from fundus reflection spectra. The concentration values found in 12 healthy subjects are in excellent agreement with published data. In individual cases of pathologic fundus alterations, possible benefits to the ophthalmologic diagnostics are demonstrated.     

In vivo efficacy of bone-marrow-coated polycaprolactone scaffolds for the reconstruction of orbital defects in the pig

Alloplastic materials offer a number of advantages over bone autografts in the reconstruction of craniofacial defects. These include: lack of donor site morbidity, unlimited quantities of available material, and the possibility to conform exactly to the defect. An ideal bioresorbable material would degrade slowly, and have osteoconductive properties to allow replacement and remodeling by osseous tissue. This is seldom observed, the materials instead being replaced by fibrous tissue. Polycaprolactone (PCL), an FDA-approved bioresorbable polymer, has several properties that might make it suitable for reconstruction of craniofacial defects. The technique of fused deposition modeling (FDM) allows for the fabrication of highly reproducible bioresorbable 3D scaffolds. The nature of the fully interconnected pore network might enhance vascular ingrowth and osteoconductive properties. It was hypothesized that coating the scaffolds in bone marrow might enhance bone formation due to the osteoinductive nature of the bone-marrow mesenchymal cells. This study aimed to test these hypotheses in the pig model. Defects measuring 2 x 2 cm were surgically created in each orbit of eight Yorkshire pigs. The orbits were divided into three groups: Group 1 (n=4), no reconstruction (control); Group 2 (n=6), reconstruction with no coated PCL scaffolds; and Group 3 (n=6) reconstruction with bone-marrow-coated PCL scaffolds. The results were evaluated at 3 months by histological and histomorphometric analyses. The defects in Group 1 were covered with fibrous scar tissue. The shape of the reconstructed area was insufficient. The defects in Groups 2 and 3 were reconstructed correctly. In Group 2 the noncoated scaffolds showed 4.5% of new bone formation compared with 14.1% in Group 3, which is statistically significant (p<0.05). The entirely interconnected 3D polycaprolactone scaffold seems to be a promising material. It induces the bone ingrowth required for reconstructing craniofacial and orbital defects. Further long-term evaluations of these PCL scaffolds must be made in order to confirm these conclusions.     

Stabilities of free and complexed human immunodeficiency virus p24 antigens during short- and long-term storage.

By the standard p24 assay there was a 25 to 27% decrease in free p24 antigen in serum after storage at 4 degrees C over 14 days but no loss at -70 degrees C. There was no loss at either temperature by the immune complex dissociation (ICD) procedure. Furthermore, there was no significant loss of detectable p24 in serum by either the ICD or the standard p24 assay after 700 days of storage at -70 degrees C.     

Veridical causal inference using propensity score methods for comparative effectiveness research with medical claims

Health Services and Outcomes Research Methodology - Medical insurance claims are becoming increasingly common data sources to answer a variety of questions in biomedical research. Although...     

Development and Validation of the Sexual and Reproductive Empowerment Scale for Adolescents and Young Adults

PurposeWe developed and validated a measure that assesses the latent construct of sexual and reproductive empowerment among adolescents and young adults. A specific measure for this group is critical because of their unique life stage and circumstances, which often includes frequent changes in sexual partners and involvement from parents in decision-making.MethodsAfter formative qualitative research, a review of the literature, and cognitive interviews, we developed 95 items representing nine dimensions of sexual and reproductive empowerment. Items were then fielded among a national sample of young people aged 15–24 years, and those who identified as sexually active completed a 3-month follow-up survey. We conducted psychometric analysis and scale validation.ResultsExploratory factor analysis on responses from 1,117 participants resulted in the Sexual and Reproductive Empowerment Scale for Adolescents and Young Adults, containing 23 items captured by seven subscales: comfort talking with partner; choice of partners, marriage, and children; parental support; sexual safety; self-love; sense of future; and sexual pleasure. Validation using logistic regression demonstrated that the subscales were consistently associated with sexual and reproductive health information and access to sexual and reproductive health services measured at baseline and moderately associated with the use of desired contraceptive methods at 3-month follow-up.ConclusionsThe Sexual and Reproductive Empowerment Scale for Adolescents and Young Adults is a new measure that assesses young people’s empowerment regarding sexual and reproductive health. It can be used by researchers, public health practitioners, and clinicians to measure sexual and reproductive empowerment among young people.     

A comparison of postoperative respiratory complications associated with the use of desflurane and sevoflurane: a single-centre cohort study

Sevoflurane and desflurane are the most commonly used volatile anaesthetics for maintenance of anaesthesia. In this study, we aimed to evaluate the relationship between choice of volatile anaesthetic and early postoperative respiratory complications, and to address a critical knowledge gap in safety outcomes between these two commonly used agents. We performed a retrospective analysis of adult (non-cardiac surgery) patients who received sevoflurane or desflurane for the maintenance of general anaesthesia at our institution between 2005 and 2018. We evaluated the association between desflurane exposure (when compared with sevoflurane) and the primary outcome of postoperative respiratory complications, defined by early post-extubation desaturation (S_pO₂ < 90%) or re-intubation within 7 days postoperatively. Multivariable regression analyses were performed and adjusted for confounding factors, including patient, anaesthetic and surgical factors. Propensity matched, interaction and sub-group analyses were performed to assess outcomes in high-risk groups: morbidly obese (BMI > 35 kg.m⁻²); elderly (age > 65 years); and high risk of respiratory complications as well as the primary outcome at 24 h. Desflurane was used for 23,830 patients and sevoflurane for 84,608 patients. Patients exposed to desflurane did not demonstrate a reduced risk of postoperative respiratory complications when compared with sevoflurane (adjusted odds ratio 0.99, 95%CI 0.94–1.04, p = 0.598). These findings were consistent across all sub-groups of high-risk patients and in the propensity score matched cohort. In summary, desflurane use was not associated with reduced postoperative respiratory complications when compared with sevoflurane. In the context of environmental and cost concerns with volatile anaesthetic agents, our study provides important data to support organisational decisions regarding the use of desflurane.