Immunodetection methods for grass pollen allergens on western blots

A comparison is made of eight different methods to detect allergenic proteins in Western blots of rye-grass pollen extracts. Horseradish peroxidase-based enhanced chemiluminescence (ECL) provides a sensitive method for the detection of allergenic proteins. The method has been modified to use more dilute solutions of ECL substrate to reduce the background, can be applied to a standard nitrocellulose membrane, and used with Kodak X-ray film. The assays can be performed rapidly, replacing use of radiolabelled probes. Increased resolution is obtained. This makes the method suitable for detection of cDNA clones on plaque lifts, and for rapid and specific purification of proteins following immunodetection on nitrocellulose membranes.     

Detection of Antibodies in Human Sera to Streptococcal Groups A and C Carbohydrates by a Radioimmunoassay

The human lymphokine, leucocyte migration-inhibitory factor (LIF), appears to be a serine esterase and protease by virtue of its susceptibility to the irreversible enzyme inhibitor, phenylmethylsulfonyl fluoride (PMSF), and by the ability of arginine esters and amides to protect LIF against PMSF-induced inactivation. In this paper, three methods are described by which putative substrates for LIF may be investigated. Thus, molecules satisfying the substrate specificities of this lymphokine should (1) protect LIF against inactivation by PMSF, (2) reduce LIF activity in vitro on polymorphonuclear leucocytes, and (3) reduce the esterolytic activity of purified LIF-rich supernatants. The first two reactions were tested by means of the leucocyte migration agarose technique; the third reaction was tested by a sensitive enzyme assay using tritiated tosyl arginine methyl ester as substrate. Guanosine 3',5'-cyclic monophosphoric acid, which is capable of protecting LIF against PMSF-induced inhibition, also inhibited the esterolytic activity of the purified LIF preparation. Four synthetic oligopeptide substrates for trypsin, thombin and plasmin were investigated. Only one, the thrombin- and trypsin-specific benzoyl-phenylalanyl-valyl-agarine-p-nitroanilide, possessed high affinity for the LIF molecule and may therefore prove to be a potent substrate for this lymphokine.     

Contact angle, protein adsorption and osteoblast precursor cell attachment to chitosan coatings bonded to titanium

Chitosan, a derivative of the bio-polysaccharide chitin, has shown promise as a bioactive material for implant, tissue engineering and drug-delivery applications. The aim of this study was to evaluate the contact angle, protein adsorption and osteoblast precursor cell attachment to chitosan coatings bonded to titanium. Rough ground titanium (Ti) coupons were solution cast and bonded to 91.2% de-acetylated chitosan (1 wt% chitosan in 0.2% acetic acid) coatings via silane reactions. Non-coated Ti was used as controls. Samples were sterilized by ethylene oxide gas prior to experiments. Contact angles on all surfaces were measured using water. 5 x 10(4) cells/ml of ATCC CRL 1486 human embryonic palatal mesenchyme (HEPM) cells, an osteoblast precursor cell line, were used for the cell attachment study. SEM evaluations were performed on cells attached to all surfaces. Contact angles and cell attachment on all surfaces were statistically analyzed using ANOVA. The chitosan-coated surfaces (76.4 +/- 5.1 degrees) exhibited a significantly greater contact angle compared to control Ti surfaces (32.2 +/- 6.1 degrees). Similarly, chitosan-coated surfaces exhibited significantly greater (P < 0.001) albumin adsorption, fibronectin adsorption and cell attachment, as compared to the control Ti surfaces. Coating chitosan on Ti surfaces decreased the wettability of the Ti, but increased protein adsorption and cell attachment. Increased protein absorption and cell attachment on the chitosan-coated Ti may be of benefit in enhancing osseointegration of implant devices.     

Social Media Content of Idiopathic Pulmonary Fibrosis Groups and Pages on Facebook: Cross-sectional Analysis

BackgroundPatients use Facebook as a resource for medical information. We analyzed posts on idiopathic pulmonary fibrosis (IPF)-related Facebook groups and pages for the presence of guideline content, user engagement, and usefulness.ObjectiveThe objective of this study was to describe and analyze posts from Facebook groups and pages that primarily focus on IPF-related content.MethodsCross-sectional analysis was performed on a single date, identifying Facebook groups and pages resulting from separately searching “IPF” and “idiopathic pulmonary fibrosis.” For inclusion, groups and pages needed to meet either search term and be in English, publicly available, and relevant to IPF. Every 10th post was assessed for general characteristics, source, focus, and user engagement metrics. Posts were analyzed for presence of IPF guideline content, useful scientific information (eg, scientific publications), useful support information (eg, information about support groups), and potentially harmful information.ResultsEligibility criteria were met by 12 groups and 27 pages, leading to analysis of 523 posts. Of these, 42% contained guideline content, 24% provided useful support, 20% provided useful scientific information, and 5% contained potentially harmful information. The most common post source was nonmedical users (85%). Posts most frequently focused on IPF-related news (29%). Posts containing any guideline content had fewer likes or comments and a higher likelihood of containing potentially harmful content. Posts containing useful supportive information had more likes, shares, and comments.ConclusionsFacebook contains useful information about IPF, but posts with misinformation and less guideline content have higher user engagement, making them more visible. Identifying ways to help patients with IPF discriminate between useful and harmful information on Facebook and other social media platforms is an important task for health care professionals.     

Engineered NS1 for Sensitive,Specific Zika Virus Diagnosis from Patient Serology

Dengue virus (DENV) and Zika virus (ZIKV) belong to the Flaviviridae family of viruses spread by Aedes aegypti mosquitoes in tropical and subtropical areas. Accurate diagnostic tests to differentiate the 2 infections are necessary for patient management and disease control. Using characterized ZIKV and DENV patient plasma in a blind manner, we validated an ELISA and a rapid immunochromatographic test for ZIKV detection. We engineered the ZIKV nonstructural protein 1 (NS1) for sensitive serologic detection with low cross reactivity against dengue and developed monoclonal antibodies specific for the ZIKV NS1 antigen. As expected, the serologic assays performed better with convalescent than acute plasma samples; the sensitivity ranged from 71% to 88%, depending on the performance of individual tests (IgM/IgG/NS1). Although serologic tests were generally less sensitive with acute samples, our ZIKV NS1 antibodies were able to complement the serologic tests to achieve greater sensitivity for detecting early infections.     

The Hospital Frailty Risk Score is Not an Accurate Predictor of Treatment Costs for Total Joint Replacement Patients in a Medicare Bundled Payment Population

BackgroundMedically complex patients require more resources and experience higher costs within total joint arthroplasty (TJA) bundled payment models. While risk adjustment would be beneficial for such patients, no tool currently exists which can reliably identify these patients preoperatively. The purpose of this study is to determine if the Hospital Frailty Risk Score (HFRS) is a valid predictor of high-TJA treatment costs.MethodsRetrospective analysis was performed on patients who underwent primary TJA between 2015 and 2020 from a single large orthopedic practice. ICD-10 codes from an institutional database were used to calculate HFRS. Cost data including inpatient, postacute, and episode of care (EOC) costs were collected. Charlson comorbidity index, demographics, readmissions, and complications were analyzed.Results4936 patients had a calculable HFRS and those with intermediate and high scores experienced more frequent readmissions/complications after TJA, as well as higher EOC costs. However, HFRS did not reliably predict EOC costs, yielding a sensitivity of 49% and specificity of 66%. Multivariate analysis revealed that both patient age and sex are superior individual cost predictors when compared with HFRS. Secondary analyses indicated that HFRS more effectively predicts TJA complications and readmissions but is still nonideal for clinical applications.ConclusionHFRS has poor sensitivity as a predictor of high-EOC costs for TJA patients but has adequate specificity for predicting postoperative readmissions and complications. Further research is needed to develop a scale that can appropriately predict orthopedic cost outcomes.     

Kidney recipients with allograft failure,transition of kidney care (KRAFT): A survey of contemporary practices of transplant providers

Kidney allograft failure and return to dialysis carry a high risk of morbidity. A practice survey was developed by the AST Kidney Pancreas Community of Practice workgroup and distributed electronically to the AST members. There were 104 respondents who represented 92 kidney transplant centers. Most survey respondents were transplant nephrologists at academic centers. The most common approach to immunosuppression management was to withdraw the antimetabolite first (73%), while only 12% responded they would withdraw calcineurin inhibitor (CNI) first. More than 60% reported that the availability of a living donor is the most important factor in their decision to taper immunosuppression, followed by risk of infection, risk of sensitization, frailty, and side effects of medications. More than half of respondents reported that embolization was either not available or offered to less than 10% as an option for surgical intervention. Majority reported that ≤50% of failed allograft patients were re-listed before dialysis, and less than a quarter of transplant nephrologists performed frequent visits with their patients with failed kidney allograft after they return to dialysis. This survey demonstrates heterogeneity in the care of patients with a failing allograft and the need for more evidence to guide improvements in clinical practice related to transition of care.     

Drug and Alcohol Use with Condomless Anal Sex among Men Who Have Sex with Men in Melbourne,Australia: A Retrospective Data Analysis from 2011 to 2017

Rises in condomless anal sex among men who have sex with men (MSM) have been reported over the last decade but there is less certainty about the role that drugs, alcohol, play in this change. We examined the changes in drug and alcohol use among 22,255 MSM reporting condomless anal sex at Melbourne Sexual Health Centre in 2011–2017. There was a 7% annual increase in using drugs before and/or during condomless anal sex but a 3% annual reduction in condomless anal sex while drunk. MSM taking PrEP were more likely to report condomless anal sex with drug use (AOR: 1.21; 95%CI: 1.07–1.37) and alcohol use (AOR: 1.29; 95%CI: 1.14–1.46) compared with MSM not taking PrEP.

     

A simple scoring system to estimate perioperative mortality following liver resection for primary liver malignancy—the Hepatectomy Risk Score (HeRS)

BackgroundSelection of the optimal treatment modality for primary liver cancers remains complex, balancing patient condition, liver function, and extent of disease. In individuals with preserved liver function, liver resection remains the primary approach for treatment with curative intent but may be associated with significant mortality. The purpose of this study was to establish a simple scoring system based on Model for End-stage Liver Disease (MELD) and extent of resection to guide risk assessment for liver resections.MethodsThe 2005–2015 NSQIP database was queried for patients undergoing liver resection for primary liver malignancy. We first developed a model that incorporated the extent of resection (1 point for major hepatectomy) and a MELD-Na score category of low (MELD-Na =6, 1 point), medium (MELD-Na =7–10, 2 points) or high (MELD-Na >10, 3 points) with a score range of 1–4, called the Hepatic Resection Risk Score (HeRS). We tested the predictive value of this model on the dataset using logistic regression. We next developed an optimal multivariable model using backwards sequential selection of variables under logistic regression. We performed K-fold cross validation on both models. Receiver operating characteristics were plotted and the optimal sensitivity and specificity for each model were calculated to obtain positive and negative predictive values.ResultsA total of 4,510 patients were included. HeRS was associated with increased odds of 30-day mortality [HeRS =2: OR =3.23 (1.16–8.99), P=0.025; HeRS =3: OR =6.54 (2.39–17.90), P<0.001; HeRS =4: OR =13.69 (4.90–38.22), P<0.001]. The AUC for this model was 0.66. The AUC for the optimal multivariable model was higher at 0.76. Under K-fold cross validation, the positive predictive value (PPV) and negative predictive value (NPV) of these two models were similar at PPV =6.4% and NPV =97.7% for the HeRS only model and PPV =8.4% and NPV =98.1% for the optimal multivariable model.ConclusionsThe HeRS offers a simple heuristic for estimating 30-day mortality after resection of primary liver malignancy. More complicated models offer better performance but at the expense of being more difficult to integrate into clinical practice.