Engineering luminescent biosensors for point-of-care SARS-CoV-2 antibody detection.

Current serology tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies mainly take the form of enzyme-linked immunosorbent assays, chemiluminescent microparticle immunoassays or lateral flow assays, which are either laborious, expensive or lacking sufficient sensitivity and scalability. Here we present the development and validation of a rapid, low-cost, solution-based assay to detect antibodies in serum, plasma, whole blood and to a lesser extent saliva, using rationally designed split luciferase antibody biosensors. This new assay, which generates quantitative results in 30 min, substantially reduces the complexity and improves the scalability of coronavirus disease 2019 (COVID-19) antibody tests. This assay is well-suited for point-of-care, broad population testing, and applications in low-resource settings, for monitoring host humoral responses to vaccination or viral infection.

Multimodality imaging of pancreas-kidney transplants.

Simultaneous pancreas-kidney transplant remains a treatment option for patients with insulin-dependent diabetes mellitus type 1, aimed at restoring normoglycemia, alleviating insulin dependency, avoiding diabetic nephropathy, and thereby improving the quality of life. Imaging remains critical in the assessment of these transplant grafts. Ultrasound with Doppler remains the primary imaging modality for establishing baseline assessment of the graft as well as for evaluating vascular, parenchymal, and perigraft complications. Noncontrast MR imaging is preferred over non-contrast CT for evaluation of parenchymal or perigraft complications in patients with decreased renal function, although contrast-enhanced CT/MR imaging may be obtained following multidisciplinary consultation in cases with high clinical and laboratory suspicion for graft dysfunction. Catheter angiography is reserved primarily for therapeutic intervention in suspected or confirmed vascular complications. An understanding of the surgical techniques and imaging appearance of a normal graft is crucial to identify potential complications and direct timely management. This article provides an overview of surgical techniques, normal imaging appearance, as well as the spectrum of imaging findings and potential complications in pancreas-kidney transplants.

Engineering luminescent biosensors for point-of-care SARS-CoV-2 antibody detection.

Current serology tests for SARS-CoV-2 antibodies mainly take the form of enzyme-linked immunosorbent assays or lateral flow assays, with the former being laborious and the latter being expensive and often lacking sufficient sensitivity and scalability. Here we present the development and validation of a rapid, low-cost solution-based assay to detect antibodies in serum, plasma, whole blood, and saliva, using rationally designed split luciferase antibody biosensors (spLUC). This new assay, which generates quantitative results in as short as 5 minutes, substantially reduces the complexity and improves the scalability of COVID-19 antibody tests for point-of-care and broad population testing.

Engineering luminescent biosensors for point-of-care SARS-CoV-2 antibody detection

Current serology tests for SARS-CoV-2 antibodies mainly take the form of enzyme-linked immunosorbent assays or lateral flow assays, with the former being laborious and the latter being expensive and often lacking sufficient sensitivity and scalability. Here we present the development and validation of a rapid, low-cost solution-based assay to detect antibodies in serum, plasma, whole blood, and saliva, using rationally designed split luciferase antibody biosensors (spLUC). This new assay, which generates quantitative results in as short as 5 minutes, substantially reduces the complexity and improves the scalability of COVID-19 antibody tests for point-of-care and broad population testing.

Computational design of a modular protein sense-response system.

Sensing and responding to signals is a fundamental ability of living systems, but despite substantial progress in the computational design of new protein structures, there is no general approach for engineering arbitrary new protein sensors. Here, we describe a generalizable computational strategy for designing sensor-actuator proteins by building binding sites de novo into heterodimeric protein-protein interfaces and coupling ligand sensing to modular actuation through split reporters. Using this approach, we designed protein sensors that respond to farnesyl pyrophosphate, a metabolic intermediate in the production of valuable compounds. The sensors are functional in vitro and in cells, and the crystal structure of the engineered binding site closely matches the design model. Our computational design strategy opens broad avenues to link biological outputs to new signals.

Cytochrome 2C19 and paraoxonase-1 polymorphisms and clopidogrel resistance in ischemic heart disease patients.

Aim: Polymorphisms in cytochrome P450 (CYP) 2C19 and paraoxonase-1 (PON-1) genes are thought to be involved in clopidogrel high on treatment reactivity in ischemic heart disease (IHD) patients. Methods: A total of 240 patients with IHD were screened for CYP2C19 loss-of-function alleles (LOF; *2, *3) and PON-1 Q192R. Patients were classified as responders and nonresponders to clopidogrel based upon platelet aggregation studies. Genotyping of the CYP2C19 and PON-1 allele was carried out by PCR-RFLP. Results: Results showed that 14.3% of the patients were nonresponders, whereas 85.7% were responders to the clopidogrel therapy. CYP2C19*3 allele showed significant association with clopidogrel high on treatment reactivity in IHD patients. Conclusion: Result of our study demonstrate that IHD patients with CYP2C19*3 allele can face the problem of clopidogrel high on treatment reactivity in Punjabi Pakistani population.

Late presentation of ALCAPA syndrome in an elderly Asian lady.

Coronary artery anomalies are often discovered incidentally during cardiac catheterization or computed tomography coronary angiography and may involve the affected coronary artery origin and its course. Coronary artery anomalies are associated with congenital heart disease. The affected coronary arteries may have an unusual high take off origin, origin from contralateral or non-coronary sinus, origin from the pulmonary artery, single coronary system or coronary artery fistula.

Automated detection of glaucoma using structural and non structural features.

Glaucoma is a chronic disease often called "silent thief of sight" as it has no symptoms and if not detected at an early stage it may cause permanent blindness. Glaucoma progression precedes some structural changes in the retina which aid ophthalmologists to detect glaucoma at an early stage and stop its progression. Fundoscopy is among one of the biomedical imaging techniques to analyze the internal structure of retina. Our proposed technique provides a novel algorithm to detect glaucoma from digital fundus image using a hybrid feature set. This paper proposes a novel combination of structural (cup to disc ratio) and non-structural (texture and intensity) features to improve the accuracy of automated diagnosis of glaucoma. The proposed method introduces a suspect class in automated diagnosis in case of any conflict in decision from structural and non-structural features. The evaluation of proposed algorithm is performed using a local database containing fundus images from 100 patients. This system is designed to refer glaucoma cases from rural areas to specialists and the motivation behind introducing suspect class is to ensure high sensitivity of proposed system. The average sensitivity and specificity of proposed system are 100 and 87 % respectively.

Pulmonary function testing and outcomes in subjects with heart failure listed for heart transplantation.

BACKGROUND: Impaired spirometric parameters have been reported in patients with stage C heart failure and portend worse outcomes in these patients. The impact of spirometric parameters on outcomes in patients with stage D heart failure listed for heart transplantation is unknown. METHODS: We collected data on consecutive subjects listed for heart transplantation and examined the association of FEV1, FVC, and FEV1/FVC with (1) death or left ventricular assist device implantation (primary end point) and (2) death, left ventricular assist device implantation, or urgent transplantation (secondary end point). In a secondary analysis, we examined the association of baseline spirometry with post-transplant outcomes. RESULTS: Among 187 subjects (53 ± 10 y old, 17.1% women, 69.5% white subjects, 28.9% black subjects), there were 19 deaths, 28 left ventricular assist device implantations, and 74 urgent transplantations (primary end point of 25.1%, secondary end point of 64.7%) after a median of 5.5 months (interquartile range of 2.3-15.2). For FEV1, the hazard ratios for the primary and secondary end points were 0.93 (95% CI 0.61-1.41, P = .72) and 0.94 (95% CI 0.72-1.21, P = .62) per L, respectively. The hazard ratios of FVC were 0.90 (95% CI 0.65-1.25, P = .52) and 0.92 (95% CI 0.76-1.13, P = .43) per L, respectively. Impairment patterns (obstructive, restrictive, mixed) were not associated with risk for events. There was no interaction of spirometric parameters with smoking or lung disease for outcomes. Baseline spirometry was not associated with perioperative 30-d mortality (1.4%) and 1-y post-transplant survival (97.1%). CONCLUSIONS: In contrast to stage C subjects with heart failure, spirometric parameters were not associated with outcomes in this homogeneous stage D heart failure population.

The entrapped and unravelled coronary wire.

No abstract available.

Motor and sensory neuropathy due to myelin infolding and paranodal damage in a transgenic mouse model of Charcot-Marie-Tooth disease type 1C.

Charcot-Marie-Tooth disease type 1C (CMT1C) is a dominantly inherited motor and sensory neuropathy. Despite human genetic evidence linking missense mutations in SIMPLE to CMT1C, the in vivo role of CMT1C-linked SIMPLE mutations remains undetermined. To investigate the molecular mechanism underlying CMT1C pathogenesis, we generated transgenic mice expressing either wild-type or CMT1C-linked W116G human SIMPLE. Mice expressing mutant, but not wild type, SIMPLE develop a late-onset motor and sensory neuropathy that recapitulates key clinical features of CMT1C disease. SIMPLE mutant mice exhibit motor and sensory behavioral impairments accompanied by decreased motor and sensory nerve conduction velocity and reduced compound muscle action potential amplitude. This neuropathy phenotype is associated with focally infolded myelin loops that protrude into the axons at paranodal regions and near Schmidt-Lanterman incisures of peripheral nerves. We find that myelin infolding is often linked to constricted axons with signs of impaired axonal transport and to paranodal defects and abnormal organization of the node of Ranvier. Our findings support that SIMPLE mutation disrupts myelin homeostasis and causes peripheral neuropathy via a combination of toxic gain-of-function and dominant-negative mechanisms. The results from this study suggest that myelin infolding and paranodal damage may represent pathogenic precursors preceding demyelination and axonal degeneration in CMT1C patients.

Lay representations of chronic diseases in Ghana: implications for primary prevention.

BACKGROUND: Ghana's health system is ill-equipped to tackle the country's double burden of infectious and chronic diseases. The current focus is on empowering lay communities to adopt healthy practices to prevent chronic diseases. Understanding how individuals make sense of health, illness and chronic illnesses is an important first step to developing practical interventions. METHODS: Six focus group discussions with lay people (N= 51) in Accra, Nkoranza and Kintampo to explore: (1) knowledge of prevalent chronic diseases in Ghana; (2) chronic disease causal theories; and (3) chronic disease treatment. RESULTS: Nineteen conditions were listed cumulatively. Diabetes and hypertension were listed by all groups. Rural groups included HIV/AIDS on their list as well as diseases with alleged spiritual roots, in particular epilepsy and sickle cell disease. Multiple causal theories were presented for diabetes and hypertension; cancers were attributed to toxic foods; asthma attributed to environmental pollution. Biomedical care was preferred by the majority. Lay representations were drawn from multiple sources: medical professionals and chronically ill individuals were the most legitimate knowledge sources. CONCLUSION: This study provides insights on how lay representations of common chronic diseases and their major risk factors provide public health specialists with the conceptual tools to develop primary prevention strategies. The first challenge will be to train health experts to provide accurate information in practical language that lay people can understand and apply to their daily lives. A second challenge will be to develop sustainable behaviour-change interventions. Best practices from other African countries can inform interventions in Ghana.

The behaviour of health workers in an era of cost sharing: Ghana's drug cash and carry system.

This qualitative study aimed to assess possible changes in prescription patterns and resultant implications for the quality of care delivered in three southern districts of Ghana after the introduction of a full cost recovery scheme for drugs in 1992. While the availability of safe and effective drugs has improved especially in rural areas, not all patients are able to meet the cost for required medication. This has influenced the behaviour of most prescribers, who now take economical limitations into account. As a result, poorer patients may either take fewer drugs or smaller quantities than medically indicated, with possible ensuing consequences for public health. Overall, the cash-and-carry scheme does not appear to have changed health workers' attitudes towards patients; where such behavioural changes occurred they seemed to be due to personnel shortages. Generally, patients in rural facilities reported greater satisfaction with the care they received than urban residents; and medical assistants were perceived as friendlier than both nurses and doctors.

Cost recovery in Ghana: are there any changes in health care seeking behaviour?

The study aimed to investigate the impact on health care seeking behaviour of the cost-sharing policies introduced in Ghana between 1985 and 1992. Qualitative research techniques were used to investigate the behaviour of patients after the introduction of these policies. Focus group discussions of cohorts of the population and in-depth interviews of health workers and selected opinion leaders were used to collect data from rural and urban health care facilities in three districts of Ghana. The study findings indicate that the cost recovery policies have led to an increase in self-medication and other behaviours aimed at cost-saving. At the same time, there is a perception of an improvement in the drug supply situation and general health delivery in government facilities. The study advocated enhanced training of drug peddlers and attendants at drug stores, especially in rural areas. User fee exemption criteria need to be worked out properly and implemented so that the very needy are not precluded from seeking health care at hospitals and clinics.

Willingness to pay for health insurance in a developing economy. A pilot study of the informal sector of Ghana using contingent valuation.

In the midst of high cost of health care both at the macro and micro levels, health insurance becomes a viable alternative for financing health care in Ghana. It is also a way of mobilising private funds for improving health care delivery at the macro level. This study uses a contingent valuation method to assess the willingness of households in the informal sector of Ghana to join and pay premiums for a proposed National Health Insurance scheme. Focus group discussions, in-depth and structured interviews were used to collect data for the study. There was a high degree of acceptance of health insurance in all the communities surveyed. Over 90% of the respondents agreed to participate in the scheme and up to 63.6% of the respondents were willing to pay a premium of 5000 cents or $3.03 a month for a household of five persons. Using an ordered probit model, the level of premiums households were willing to pay were found to be influenced by dependency ratio, income or whether a household has difficulty in paying for health care or not, sex, health care expenditures and education. As income increases, or the proportion of unemployed household members drop, people are willing to pay higher premiums for health insurance.