Biomedical text readability after hypernym substitution with fine-tuned large language models

The advent of patient access to complex medical information online has highlighted the need for simplification of biomedical text to improve patient understanding and engagement in taking ownership of their health. However, comprehension of biomedical text remains a difficult task due to the need for domain-specific expertise. We aimed to study the simplification of biomedical text via large language models (LLMs) commonly used for general natural language processing tasks involve text comprehension, summarization, generation, and prediction of new text from prompts. Specifically, we finetuned three variants of large language models to perform substitutions of complex words and word phrases in biomedical text with a related hypernym. The output of the text substitution process using LLMs was evaluated by comparing the pre- and post-substitution texts using four readability metrics and two measures of sentence complexity. A sample of 1,000 biomedical definitions in the National Library of Medicine's Unified Medical Language System (UMLS) was processed with three LLM approaches, and each showed an improvement in readability and sentence complexity after hypernym substitution. Readability scores were translated from a pre-processed collegiate reading level to a post-processed US high-school level. Comparison between the three LLMs showed that the GPT-J-6b approach had the best improvement in measures of sentence complexity. This study demonstrates the merit of hypernym substitution to improve readability of complex biomedical text for the public and highlights the use case for fine-tuning open-access large language models for biomedical natural language processing.

The empty pelvis syndrome: a core data set from the PelvEx collaborative

BACKGROUND

Empty pelvis syndrome (EPS) is a significant source of morbidity following pelvic exenteration (PE), but is undefined. EPS outcome reporting and descriptors of radicality of PE are inconsistent; therefore, the best approaches for prevention are unknown. To facilitate future research into EPS, the aim of this study is to define a measurable core outcome set, core descriptor set and written definition for EPS. Consensus on strategies to mitigate EPS was also explored.

METHOD

Three-stage consensus methodology was used: longlisting with systematic review, healthcare professional event, patient engagement, and Delphi-piloting; shortlisting with two rounds of modified Delphi; and a confirmatory stage using a modified nominal group technique. This included a selection of measurement instruments, and iterative generation of a written EPS definition.

RESULTS

One hundred and three and 119 participants took part in the modified Delphi and consensus meetings, respectively. This encompassed international patient and healthcare professional representation with multidisciplinary input. Seventy statements were longlisted, seven core outcomes (bowel obstruction, enteroperineal fistula, chronic perineal sinus, infected pelvic collection, bowel obstruction, morbidity from reconstruction, re-intervention, and quality of life), and four core descriptors (magnitude of surgery, radiotherapy-induced damage, methods of reconstruction, and changes in volume of pelvic dead space) reached consensus-where applicable, measurement of these outcomes and descriptors was defined. A written definition for EPS was agreed.

CONCLUSIONS

EPS is an area of unmet research and clinical need. This study provides an agreed definition and core data set for EPS to facilitate further research.

Entropy removal of medical diagnostics

Shannon entropy is a core concept in machine learning and information theory, particularly in decision tree modeling. To date, no studies have extensively and quantitatively applied Shannon entropy in a systematic way to quantify the entropy of clinical situations using diagnostic variables (true and false positives and negatives, respectively). Decision tree representations of medical decision-making tools can be generated using diagnostic variables found in literature and entropy removal can be calculated for these tools. This concept of clinical entropy removal has significant potential for further use to bring forth healthcare innovation, such as quantifying the impact of clinical guidelines and value of care and applications to Emergency Medicine scenarios where diagnostic accuracy in a limited time window is paramount. This analysis was done for 623 diagnostic tools and provided unique insights into their utility. For studies that provided detailed data on medical decision-making algorithms, bootstrapped datasets were generated from source data to perform comprehensive machine learning analysis on these algorithms and their constituent steps, which revealed a novel and thorough evaluation of medical diagnostic algorithms.

Network Analysis of Academic Medical Center Websites in the United States

Healthcare resources are published annually in repositories such as the AHA Annual Survey Database^TM. However, these data repositories are created via manual surveying techniques which are cumbersome in collection and not updated as frequently as website information of the respective hospital systems represented. Also, this resource is not widely available to patients in an easy-to-use format. Network analysis techniques have the potential to create topological maps which serve to aid in pathfinding for patients in their search for healthcare services. This study explores the topological structure of forty United States academic health center websites. Network analysis is utilized to analyze and visualize 48,686 webpages. Several elements of network structure are examined including basic network properties, and centrality measures distributions. The Louvain community detection algorithm is used to examine the extent to which these techniques allow identification of healthcare resources within networks. The results indicate that websites with related healthcare services tend to form observable clusters useful in mapping key resources within a hospital system.

Primary Perspectives in Meme Utilization as a Digital Driver for Medical Community Engagement and Education Mobilization: Pre-Post Study

BACKGROUND

Memes have gone "viral," gaining increasing prominence as an effective communications strategy based on their unique ability to engage, educate, and mobilize target audiences in a call to action through a cost-efficient and culturally relevant approach. Within the medical community in particular, visual media has evolved as a means to influence clinical knowledge transfer. To this end, the GetWaivered (GW) project has leveraged memes as part of a behavioral economics toolkit to address one of the most critical public health emergencies of our time-the 20-year opioid epidemic. As part of a multidimensional digital awareness campaign to increase Drug Enforcement Administration (DEA)-X waiver course registration, GW investigated the results of meme usage in terms of impressions, website traffic, and ultimately user acquisition, as determined by web-based training enrollment and attendance outcomes.

OBJECTIVE

The objective of this study was to determine the efficacy of implementing humor-based promotional content versus the traditional educational model, and how the translation of the increase in engagement would increase the participant count and website traffic for GW's remote DEA-X waiver training.

METHODS

The approach to this study was based on 2 time frames (pre- and postcampaign). During April-July 2021, we developed a campaign via advertisements on Facebook, Twitter, Instagram, and the GW website to expand outreach. These memes targeted medical professionals with the ability to prescribe buprenorphine. The time frame of this campaign measured engagement metrics and compared values to preceding months (January-March 2021) for our GetWaivered website and social media pages, which translated to registrants for our remote DEA-X waiver training.

RESULTS

By the end of July 2021, a total of 9598 individuals had visited the GW website. There was an average of 79.3 visitors per day, with the lowest number of daily visitors being 0 and the highest being 575.

CONCLUSIONS

The use of memes may provide a medium for social media engagement (likes, comments, and shares) while influencing viewers to pursue a proposed action, such as e-training registration.

Minimum standards of pelvic exenterative practice: PelvEx Collaborative guideline

This document outlines the important aspects of caring for patients who have been diagnosed with advanced pelvic cancer. It is primarily aimed at those who are establishing a service that adequately caters to this patient group. The relevant literature has been summarized and an attempt made to simplify the approach to management of these complex cases.

Website Usability Analysis of U.S. Military Residency Programs

INTRODUCTION

The Military Match is the residency matching system for medical students attending the Uniformed Services University of Health Sciences, and the students were funded by the Health Professions Scholarship Program through the U.S. Army, Air Force, and Navy. To evaluate and compare military residency programs, students use residency program websites. Often, the residency program's website serves as a key source, or the only point of reference, when considering residency options, especially during times when face-to-face interactions are limited.This report aims to provide a systematic evaluation of military residency programs and their websites.

MATERIALS AND METHODS

Utilizing a previously published website usability scoring system, military residency programs were categorized to objectively and quantitatively analyze their websites. Usability was divided into four categories for quantifiable analysis: accessibility, marketing, content quality, and technology. The methodology for this analysis was replicated from published reports that have examined healthcare website usability. Each website was analyzed and scored in four categories: accessibility, content quality, marketing, and technology. A "General Usability" score was calculated for each website using a composite of the key factors within the four categories. An overall score was generated utilizing the weighted percentage across all four categories. To address deficiencies of the original methodology, a secondary analysis was performed on the listed websites utilizing an automated methodology for website usability.

RESULTS

A comprehensive list of 125 Accreditation Council for Graduate Medical Education U.S. Military residency program websites was compiled. Of these, 96 programs and 106 websites were evaluated. The primary analysis employing usability methodology identified technology as the highest ranked category with a score of 0.749 (SD ± 0.039) (SE 0.005) (P < .05). Marketing and content quality were the lowest scoring categories with mean scores of 0.414 (SD ± 0.054) (SE 0.006) and 0.428 (SD ± 0.229) (SE 0.027), respectively (P < .05). There was no significant difference in overall usability rankings or scores among the 96 residency program websites across the three branches (P < .05).Secondary analysis with the new usability methodology demonstrated military residency websites to exhibit more external backlinking compared to internal backlinking (P < 0.05) and no social media backlinking to any of the 106 analyzed websites. When comparing the three services, the Army had significantly lower external backlinking ranking 43.4 (P < .05) and overall backlinking ranking 56.4 (P < 0.05) when compared to the Navy (mean 48.8 and 71.7, and 43.4). There were no other differences in backlinking rankings across the three branches.

CONCLUSIONS

Residency websites have become a primary way to communicate information to applicants. By assessing the overall usability of the various military residency websites, we determined the effectiveness of these websites to relay information to prospective students interested in applying for military residency. We predict that by improving website accessibility, residency programs increase their effectiveness at communicating information to potential applicants and increase interest in military residency programs.

Looking back on forward-looking COVID models

Covid Act Now (CAN) developed an epidemiological model that takes various non-pharmaceutical interventions (NPIs) into account and predicts viral spread and subsequent health outcomes. In this study, the projections of the model developed by CAN were back-tested against real-world data, and it was found that the model consistently overestimated hospitalizations and deaths by 25%–100% and 70%–170%, respectively, due in part to an underestimation of the efficacy of NPIs. Other COVID models were also back-tested against historical data, and it was found that all models generally captured the potential magnitude and directionality of the pandemic in the short term. There are limitations to epidemiological models, but understanding these limitations enables these models to be utilized as tools for data-driven decision-making in viral outbreaks. Further, it can be valuable to have multiple, independently developed models to mitigate the inaccuracies of or to correct for the incorrect assumptions made by a particular model.

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An epidemiological model was developed by Covid Act Now (CAN)

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The performance of the model by CAN was evaluated against historical data

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The performances of several COVID models were similarly evaluated and compared

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Models were found to capture the short-term magnitude and directionality of COVID

Development of an epidemiological model by Covid Act Now (CAN) and evaluation of performance by back-testing against historical data was performed. Similar analysis was performed for several other COVID models and results compared. It was found that all models generally captured the potential magnitude and directionality of the pandemic in the short term. There are limitations to epidemiological models, but understanding these limitations enables these models to be utilized as tools for data-driven decision-making in viral outbreaks. Further, it can be valuable to have multiple, independently developed models to mitigate the inaccuracies of or to correct for the incorrect assumptions made by a particular model.

Analyzing opioid-use disorder websites in the United States: An optimized website usability study

Background

As the United States continues to tackle the opioid epidemic, it is imperative for digital healthcare organizations to provide Internet users with accurate and accessible online resources so that they can make informed decisions with regards to their health.

Objective

The primary objectives were to adapt and modify a previously established usability methodology from literature, apply this modified methodology in order to perform usability analysis of opioid-use-disorder (OUD)-related websites, and make important recommendations that OUD-related digital health organizations may utilize to improve their online presence.

Methods

A list of 208 websites (later refined) was generated for usability testing using a modified Google Search methodology. Four keywords were chosen and used in the search: “DEA-X Waiver Training”, “opioid-use-disorder (OUD) Initiatives”, “Buprenorphine Assisted Treatment”, and “Opioid-Use Disorder Websites”. Usability analysis was performed concurrently with optimization of the methodology. OUD websites were analyzed and scored on several usability categories established by previous literature.

Results

“DEA-X Waiver Training” yielded websites that scored the highest average in “Accessibility” (0.84), while “Opioid-Use Disorder Websites” yielded websites that scored the highest average in “Content Quality” (0.67). “Buprenorphine Assisted Treatment” yielded websites that scored the highest average across “Marketing” (0.52), “Technology” (0.89), “General Usability” (0.69), and “Overall Usability” (0.68). “Technology” and “Marketing” were the highest and lowest scoring usability categories, respectively. T-test analysis revealed that each usability, except “Marketing” had a pair of one or more keywords that were significantly different with a p-value that was equal to or less than 0.05.

Conclusions

Based on the study findings, we recommend that digital organizations in the OUD space should improve their “General Usability” score by making their websites easier to find online. Doing so, may allow users, especially individuals in the OUD space, to discover accurate information that they are seeking. Based on the study findings, we also made important recommendations that OUD-related digital organizations may utilize in order to improve website usability as well as overall reach.

Narratives of Undergraduate Research, Mentorship, and Teaching at UCLA

This work describes select narratives pertaining to undergraduate teaching and mentorship at UCLA Chemistry and Biochemistry by Alex Spokoyny and his junior colleagues. Specifically, we discuss how individual undergraduate researchers contributed and jump-started multiple research themes since the conception of our research laboratory. This work also describes several recent innovations in the inorganic and general chemistry courses taught by Spokoyny at UCLA with a focus of nurturing appreciation for research and creative process in sciences including the use of social media platforms.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Sono-optogenetics facilitated by a circulation-delivered rechargeable light source for minimally invasive optogenetics

Optogenetics, which uses visible light to control the cells genetically modified with light-gated ion channels, is a powerful tool for precise deconstruction of neural circuitry with neuron-subtype specificity. However, due to limited tissue penetration of visible light, invasive craniotomy and intracranial implantation of tethered optical fibers are usually required for in vivo optogenetic modulation. Here we report mechanoluminescent nanoparticles that can act as local light sources in the brain when triggered by brain-penetrant focused ultrasound (FUS) through intact scalp and skull. Mechanoluminescent nanoparticles can be delivered into the blood circulation via i.v. injection, recharged by 400-nm photoexcitation light in superficial blood vessels during circulation, and turned on by FUS to emit 470-nm light repetitively in the intact brain for optogenetic stimulation. Unlike the conventional "outside-in" approaches of optogenetics with fiber implantation, our method provides an "inside-out" approach to deliver nanoscopic light emitters via the intrinsic circulatory system and switch them on and off at any time and location of interest in the brain without extravasation through a minimally invasive ultrasound interface.

Expansion of Haematopoietic Stem and Progenitor Cells: Paving the Way for Next-Generation Haematopoietic Stem Cell Transplantation

Haematopoietic stem cell transplantation (HSCT) is now an established practice with over 70,000 transplants performed annually, and over 1.5 million around the world so far. The practice of HSCT has improved over the years due to advances in conditioning regiments, preparatory practices for patients leading up to the transplant, graft versus host disease (GVHD) and infection prophylaxis, as well as a better selection of patients. However, in many instances, the stem cells supplied to the patient may not be adequate for optimal transplantation outcomes. This may be seen in a few areas including umbilical cord blood transplantation, inadequate bone marrow, peripheral blood stem cell harvest, or gene therapy. Growing and expanding HSCs in culture would provide an increase in cell numbers prior to stem cell infusion and accelerate haematopoietic recovery, resulting in improved outcomes. Several new technologies have emerged in recent years, which have facilitated the expansion of haematopoietic stem and progenitor cells (HSPCs) in culture with good outcomes in vitro, in vivo, and in clinical trials. In this review, we will outline some of the reasons for the expansion of HSPCs as well as the new technologies facilitating the advances in HSCT.

Carborane RAFT agents as tunable and functional molecular probes for polymer materials

Carborane RAFT agents are introduced as tunable multi-purpose tools acting as ¹H NMR spectroscopic handles, Raman probes, and recognition units.

Visible-Light-Induced Olefin Activation Using 3D Aromatic Boron-Rich Cluster Photooxidants

We report a discovery that perfunctionalized icosahedral dodecaborate clusters of the type B12(OCH2Ar)12 (Ar = Ph or C6F5) can undergo photo-excitation with visible light, leading to a new class of metal-free photooxidants. Excitation in these species occurs as a result of the charge transfer between low-lying orbitals located on the benzyl substituents and an unoccupied orbital delocalized throughout the boron cluster core. Here we show how these species, photo-excited with a benchtop blue LED source, can exhibit excited-state reduction potentials as high as 3 V and can participate in electron-transfer processes with a broad range of styrene monomers, initiating their polymerization. Initiation is observed in cases of both electron-rich and electron-deficient styrene monomers at cluster loadings as low as 0.005 mol%. Furthermore, photo-excitation of B12(OCH2C6F5)12 in the presence of a less activated olefin such as isobutylene results in the production of highly branched poly(isobutylene). This work introduces a new class of air-stable, metal-free photo-redox reagents capable of mediating chemical transformations.

Bifidobacterium infantis has a beneficial effect on 5-fluorouracil-induced intestinal mucositis in rats

Intestinal mucositis is a common toxic side effect in cancer patients receiving high-dose chemotherapy. This study aimed to evaluate the beneficial effects of Bifidobacterium infantis in a rat model of intestinal mucositis induced by 5-fluorouracil (5-FU). Thirty male Sprague-Dawley rats were divided into three groups: control, 5-FU, and 5-FU + B. infantis. A single intraperitoneal injection of 5-FU (150 mg/kg) was used to induce intestinal mucositis. B. infantis (1×109 cfu) was administered for 11 days, starting from 7 days before 5-FU injection. Intestinal mucositis was evaluated based on body weight, villus height, immunohistological expression of proliferating cell nuclear antigen (PCNA) and nuclear factor kappa beta (NF-κB), levels of the pro-inflammatory factors interleukin 1 beta and tumour necrosis factor alpha, and myeloperoxidase (MPO) concentration. The results showed that the 5-FU + B. infantis group demonstrated a higher body weight and villus height, increased expression of PCNA, reduced expression of NF-κB and pro-inflammatory factors, and lower MPO concentration compared to the 5-FU group. These data suggest that probiotic B. infantis is effective in reducing chemotherapy-induced intestinal mucositis in rats.

Embolisation of Angio-Seal™ device: an unusual case of post-cardiac catheterisation limb ischaemia

We present the case of a 67-year-old male presenting with critical limb ischaemia following cardiac catheterisation. Immediately after deployment of an arterial closure device, the patient reported severe lower limb pain with impalpable pulses. Magnetic resonance angiography revealed an abrupt disruption of flow in the tibioperoneal trunk. Subsequent surgery revealed embolisation of the arterial closure device. The patient went on to make an unremarkable recovery.

Hernias are the most common cause of strangulation in patients presenting with small bowel obstruction

BACKGROUND

Small bowel obstruction (SBO) is a leading cause of admission to surgical emergency units. Strangulation is associated with a 10-fold increase in mortality. The aim of the present study was to identify the most frequent causes of strangulation in patients presenting with small bowel obstruction.

METHODS

A prospective study was conducted of all patients presenting with SBO in one teaching hospital between 2003 and 2004.

RESULTS

One hundred and sixty-one patients with symptoms and signs of small bowel obstruction were admitted. Eighty-three were confirmed with contrast studies. The male:female ratio was 1:1.6. The aetiology of obstruction was adhesions in 97 patients (60.2%), hernia in 29 (18%), malignancy in 17 (10.6%) and miscellaneous causes in 18 (11.2%). Operative procedures were performed on 74 patients (46%), 31 of them (42%) with adhesions, 25 (34%) with hernias and 18 (24%) due to other causes. Strangulated bowel occurred in 15 patients (9.3%); 12 had hernias whilst three had adhesions (P < 0.0001). Of the strangulated hernias, ten were femoral, one was inguinal and one was paraumbilical. There were seven deaths; three occurred in patients declared unfit for surgery, while four occurred post-operatively - two had strangulated bowel, the other two had advanced cancer.

CONCLUSION

Whilst adhesions are the most common cause of small bowel obstruction, hernias remain the most frequent cause of strangulation in patients presenting with this condition.

The use of structural distal femoral allografts for acetabular reconstruction. Surgical technique

BACKGROUND

Acetabular fixation during revision total hip arthroplasty in patients who have a nonsupportive superior dome and proximal migration of the acetabular component (a Paprosky Type-IIIa defect) cannot be achieved reliably with use of a hemispherical porouscoated component alone. The purposes of the present study were to determine the long-term results associated with the use of a porous-coated hemispherical acetabular component, supported with a distal femoral structural allograft, for revision at the site of a Type-IIIa defect and to determine if graft resorption leads to late failure.

METHODS

Thirty-one patients who had an acetabular reconstruction with use of a distal femoral allograft for the treatment of a Type-IIIa defect between January 1985 and December 1990 were followed annually with clinical and radiographic evaluations. At the time of the latest follow-up, eight patients had died and one patient had been lost to follow-up. One of the patients who died had had a clinical failure at 4.5 years postoperatively and was included in the analysis. Therefore, twenty-three patients, who had had an average age of sixty-one years at the time of the index procedure, were evaluated at an average of 10.3 years postoperatively.

RESULTS

Five acetabular components were re-revised because of aseptic loosening at an average of 5.3 years after the index procedure. Radiographically, all but one of the remaining components were stable and showed evidence of bone ingrowth. The average Merle D'Aubigné and Postel hip score improved from 5 points preoperatively to 10 points at the time of the latest follow-up. Allograft bone resorption, although difficult to quantitate, was observed around six of the seventeen stable components and around two of the five components that failed clinically.

CONCLUSIONS

Acetabular revision with use of a porous-coated acetabular component along with a structural distal femoral allograft for the treatment of a Type-IIIa defect demonstrated a high rate of clinical and radiographic success after an average of ten years of follow-up.

Association of malignant disease with critical leg ischaemia

BACKGROUND

The aim of the study was to determine the prevalence of malignant disease in patients with critical leg ischaemia (CLI).

METHODS

: Data for all patients with CLI presenting to a tertiary vascular unit over an 18-month interval were collected prospectively. Patients with clinical, laboratory or radiological features suggestive of malignancy were evaluated further.

RESULTS

Of 192 patients admitted with CLI, 22 (11.5 per cent) were found to have an associated malignancy; ten had lung cancer. Fifteen were anaemic on presentation. The prevalence of occult malignancy in patients with acute leg ischaemia was 16 per cent (ten of 62) compared with 9.2 per cent (12 of 130) in those with chronic CLI. Eleven of 22 of patients with CLI and malignancy died within 6 months, compared with 35 (20.6 per cent) of 170 patients with no evidence of malignancy.

CONCLUSION

A high prevalence of occult cancer was found in patients presenting with CLI; this was associated with a significantly increased mortality rate at 6 months.

The use of structural distal femoral allografts for acetabular reconstruction. Average ten-year follow-up

BACKGROUND

Acetabular fixation during revision total hip arthroplasty in patients who have a nonsupportive superior dome and proximal migration of the acetabular component (a Paprosky Type-IIIa defect) cannot be achieved reliably with use of a hemispherical porous-coated component alone. The purposes of the present study were to determine the long-term results associated with the use of a porous-coated hemispherical acetabular component, supported with a distal femoral structural allograft, for revision at the site of a Type-IIIa defect and to determine if graft resorption leads to late failure.

METHODS

Thirty-one patients who had an acetabular reconstruction with use of a distal femoral allograft for the treatment of a Type-IIIa defect between January 1985 and December 1990 were followed annually with clinical and radiographic evaluations. At the time of the latest follow-up, eight patients had died and one patient had been lost to follow-up. One of the patients who died had had a clinical failure at 4.5 years postoperatively and was included in the analysis. Therefore, twenty-three patients, who had had an average age of sixty-one years at the time of the index procedure, were evaluated at an average of 10.3 years postoperatively.

RESULTS

Five acetabular components were re-revised because of aseptic loosening at an average of 5.3 years after the index procedure. Radiographically, all but one of the remaining components were stable and showed evidence of bone ingrowth. The average Merle D'Aubigné and Postel hip score improved from 5 points preoperatively to 10 points at the time of the latest follow-up. Allograft bone resorption, although difficult to quantitate, was observed around six of the seventeen stable components and around two of the five components that failed clinically.

CONCLUSIONS

Acetabular revision with use of a porous-coated acetabular component along with a structural distal femoral allograft for the treatment of a Type-IIIa defect demonstrated a high rate of clinical and radiographic success after an average of ten years of follow-up.

A randomized study of early nasogastric versus nasojejunal feeding in severe acute pancreatitis

BACKGROUND

After 50 yr in which nasoenteric feeding was considered contraindicated in acute pancreatitis (AP), several clinical studies have shown that early nasojejunal (NJ) feeding can be achieved in most patients. A pilot study of early nasogastric (NG) feeding in patients with objectively graded severe AP proved that this approach was also feasible. A randomized study comparing NG versus NJ feeding has been performed.

METHODS

A total of 50 consecutive patients with objectively graded severe AP were randomized to receive either NG or NJ feeding via a fine bore feeding tube. The end points were markers of the acute phase response APACHE II scores and C-reactive protein (CRP) measurements, and pain patterns by visual analogue score (VAS) and analgesic requirements. Complications were monitored and comparisons made of both total hospital and intensive-care stays.

RESULTS

A total of 27 patients were randomized to NG feeding and 23 to NJ. One of those in the NJ group had a false diagnosis, thereby reducing the number to 22. Demographics were similar between the groups and no significant differences were found between the groups in APACHE II score, CRP measurement, VAS, or analgesic requirement. Clinical differences between the two groups were not significant. Overall mortality was 24.5% with five deaths in the NG group and seven in the NJ group.

CONCLUSIONS

The simpler, cheaper, and more easily used NG feeding is as good as NJ feeding in patients with objectively graded severe AP. This appears to be a useful and practical therapeutic approach to enteral feeding in the early management of patients with severe AP.

The emergency medicine department system: a study of the effects of computerization on the quality of medical records

A template based computerized medical record system known as the Emergency Medicine Department System (EMDS) was installed in the emergency department of the National University Hospital, Singapore, replacing handwritten records. A study was carried out to show how the implementation of the EMDS improved the quality of medical records. A retrospective review of old manual records and the ones generated by the EMDS was done by means of a scoring system. The raw scores represent the amount of information captured. The calculated means of scores were then used to compare the records. It was found that EMDS improves the quantity of data capture over the old records in all sections compared. This was seen regardless of the experience of the user. The use of a non-structured generic template results in less data captured compared with a structured symptom-specific template. The design of questions has a great influence in that a double-choice question captures more data than single-choice questions. Building in 'locking' or enforcement mechanisms in the EMDS also helped achieve almost full capture of critical information, such as examination time.

Antibodies to phosphatidylethanolamine and phosphatidylserine are associated with increased natural killer cell activity in non-male factor infertility patients

Antiphospholipid antibodies (APA) have been identified in patients with recurrent pregnancy loss and IVF failure. Of these, antiphosphatidylethanolamine (aPE) and antiphosphatidylserine (aPS) may have special significance. A link between increased natural killer cell activity (NKa+) and trophoblast cell apoptosis has also been reported. This study was undertaken to determine how the APA profile was associated with peripheral NK cell activity. We evaluated 197 female IVF candidates for APA and NKa. Eighty-nine patients (45%) were APA+ and of these, 51 (57%) were aPE/aPS+. Fifty-four patients (27%) had increased NK cell activity. Some 51% of APA+ and 78% of aPE/aPS+ patients had increased NK cell activity compared with 8% and 13% when APA and aPE/aPS tested negative respectively (P: < 0.0001). Non-male factor infertility patients were APA+ and NKa+ in 57% and 34% of cases respectively, compared with 19% and 13% if a pure male factor was present. Some 88% of aPE/aPS+, non-male factor patients had increased NK cell activity, compared with 12% who tested aPE/aPS negative (P: < 0.0001) and 25% of aPE/aPS+, isolated male factor patients (P: < 0.0001). These findings establish a direct relationship between APA (specifically aPE/aPS) and increased peripheral NK cell activity among non-male factor infertility patients. It is possible that APA do not directly cause reproductive failure but rather function as markers or intermediaries for an underlying, abnormal activation of cellular immunity.

Safety and immunogenicity of a live recombinant canarypox virus expressing HIV type 1 gp120 MN MN tm/gag/protease LAI (ALVAC-HIV, vCP205) followed by a p24E-V3 MN synthetic peptide (CLTB-36) administered in healthy volunteers at low risk for HIV infection. AGIS Group and L'Agence Nationale de Recherches sur Le Sida

A live recombinant canarypox vector expressing HIV-1 gpl20 MN tm/gag/protease LAI (ALVAC-HIV, vCP205) alone or boosted by a p24E-V3 MN synthetic peptide (CLTB-36) was tested in healthy volunteers at low risk for HIV infection for their safety and immunogenicity. Both antigens were well tolerated. ALVAC-HIV (vCP205) induced low levels of neutralizing antibodies against HIV-1 MN in 33% of the volunteers. None of them had detectable neutralizing antibodies against a nonsyncytium-inducing HIV-1 clade B primary isolate (Bx08). After the fourth injection of vCP205, CTL activity was detected in 33% of the volunteers and was directed against Env, Gag, and Pol. This activity was mediated by both CD4+ and CD8+ lymphocytes. On the other hand, the CLTB-36 peptide was poorly immunogenic and induced no neutralizing antibodies or CTLs. Although the ALVAC-HIV (vCP205) and CLTB-36 prime-boost regimen was not optimal, further studies with ALVAC-HIV (vCP205) are warranted because of its clear induction of a cellular immune response and utility as a priming agent for other subunit antigens such as envelope glycoproteins, pseudoparticles, or new peptides.

Correlation between beta 2-glycoprotein antibodies and antiphospholipid antibodies in patients with reproductive failure

PROBLEM

Antiphospholipid antibodies (APAs) are important in the etiology of reproductive failure. Studies have shown that binding proteins are necessary for the detection of APAs. One of these, beta 2-glycoprotein, has been shown to be necessary for detection of anticardiolipin antibodies. It is felt that some APAs may be directed to the binding protein itself, or to a combination of the binding protein and phospholipid.

METHOD OF STUDY

In this study, a comparison of APAs vs. anti beta 2-glycoprotein antibodies was performed on the sera of 123 women younger than 40 years of age with a history of reproductive failure. Antibodies to six phospholipid epitopes, cardiolipin, phosphatidyle-thanolamine, phosphatidylserine, phosphatidylinositol, phosphatidic acid, phosphatidylglycerol, and phosphatidylserine, were measured.

RESULTS

Of the 123 women tested, 33 had one or more positive immunoglobulin (Ig)G antibodies to phospholipids, of which 9 were to cardiolipin. However, only 1 of 123 women had IgG antibodies to beta 2-glycoprotein and she was APA negative. Thirty-eight of 123 women had one or more IgM antibodies to phospholipids, with none directed to cardiolipin IgM. In contrast, only 8 of the 123 women had IgM antibodies to beta 2-glycoprotein. Five of the eight patients had IgM APA; 4 of 5 had IgM antibodies to PE, 1 to PI.

CONCLUSIONS

There is no correlation between beta 2-glycoprotein antibodies and APA status in this population. To date, our most sensitive test for detecting phospholipid autoimmune-mediated in vitro fertilization failure still appears to be the ELISA assay for APA.

The selective use of heparin/aspirin therapy, alone or in combination with intravenous immunoglobulin G, in the management of antiphospholipid antibody-positive women undergoing in vitro fertilization

PROBLEM

The effect of mini-dose heparin/aspirin (H/A) alone vs. combined intravenous immunoglobulin G (IVIg) and H/A on in vitro fertilization (IVF) birthrates in women who test seropositive for antiphospholipid antibodies (APA+) was evaluated, as was the question of whether outcome is influenced by the gammaglobulin isotype(s) or the phospholipid (PL) epitope(s) to which the APAs are directed.

METHOD OF STUDY

A case-control study was conducted in three phases, spanning a 4-year period, in a multicenter clinical research environment. Six hundred eighty-seven APA+ women, who were younger than 40 years and who each, completed up to three consecutive IVF/embryo transfer cycles within a 12-month period, were given either H/A alone or H/A in combination with IVIg. Birthrates relative to the type of immunotherapy (i.e., H/A alone and H/A with IVIg) and APA profile were the main outcome measurements.

RESULTS

In phase I, 687 women who tested APA+ to one or more PL epitopes underwent two or fewer IVF attempts for a total of 1050 IVF cycles. Four hundred seventy-seven (46%) births occurred in 923 IVF cycles in which H/A alone was administered. Twenty-two (17%) births occurred after 127 IVF cycles in which H/A was not administered. In phase II, 322 of 687 women tested positive for a single APA subtype. These subjects underwent up to two consecutive IVF attempts for a total of 521 IVF cycles while receiving H/A alone. The birthrate was significantly lower for women whose APAs were directed toward phosphatidylethanolamine (PE) or phosphatidylserine (PS) involving IgG or IgM isotypes than for women who had any other APA (17% vs. 43%). In phase III, 121 women who did not achieve live births after two consecutive IVF attempts in which H/A alone was administered received IVIg in combination with H/A during their third consecutive IVF cycle. The birth rate was 41% after these IVF cycles when anti-PS or anti-PE involving IgG or IgM isotypes were present, as compared with 17% when H/A alone was administered. The IVF outcome did not improve when IVIg was administered in association with any other single APA.

CONCLUSIONS

The treatment of APA+ women with H/A alone improves IVF birthrates. This benefit is selective in that it does not apply in cases in which IgG- or IgM-related APAs are directed against PE or PS. In such cases, the addition of IVIg significantly improves the outcome.

Cloning and expression of the Moraxella catarrhalis lactoferrin receptor genes

The lactoferrin receptor genes from two strains of Moraxella catarrhalis have been cloned and sequenced. The lfr genes are arranged as lbpB followed by lbpA, a gene arrangement found in lactoferrin and transferrin receptor operons from several bacterial species. In addition, a third open reading frame, orf3, is located one nucleotide downstream of lbpA. The deduced lactoferrin binding protein A (LbpA) sequences from the two strains were found to be 99% identical, the LbpB sequences were 92% identical, and the ORF3 proteins were 98% identical. The lbpB gene was PCR amplified and sequenced from a third strain of M. catarrhalis, and the encoded protein was found to be 77% identical and 84% similar to the other LbpB proteins. Recombinant LbpA and LbpB proteins were expressed from Escherichia coli, and antisera raised to the purified proteins were used to assess antigenic conservation in a panel of M. catarrhalis strains. The recombinant proteins were tested for the ability to bind human lactoferrin following gel electrophoresis and electroblotting, and rLbpB, but not rLbpA, was found to bind lactoferrin. Bactericidal antibody activity was measured, and while the anti-rLbpA antiserum was not bactericidal, the anti-rLbpB antisera were found to be weakly bactericidal. Thus, LbpB may have potential as a vaccine candidate.

A 20-kilodalton N-terminal fragment of the D15 protein contains a protective epitope(s) against Haemophilus influenzae type a and type b

A conserved 80-kDa minor outer membrane protein, D15, of Haemophilus influenzae has been shown to be a protective antigen in laboratory animals against H. influenzae type a (Hia) or type b (Hib) infection. To localize the protective B-cell epitope(s) within the D15 protein and to further explore the possibility of using synthetic peptides as vaccine antigens, a 20-kDa N-terminal fragment of D15 protein (truncated D15 [tD15]) was expressed as a fusion protein with glutathione S-transferase in Escherichia coli. The tD15 moiety was cleaved from glutathione S-transferase by using thrombin and purified to homogeneity. The purified soluble tD15 appeared to contain immunodominant protective epitope(s) against Hia and Hib, since rabbit antisera directed against tD15 were capable of protecting infant rats from Hia or Hib bacteremia. The ease of purification of soluble tD15, therefore, makes it a better candidate antigen than the full-length recombinant D15 which is produced as inclusion bodies in E. coli. Furthermore, both the purified tD15 fragment and a mixture of tD15-derived peptides spanning amino acid residues 93 to 209 of the mature D15 protein were capable of inhibiting the protection against Hib conferred on infant rats by rabbit anti-tD15 antiserum, indicating that the protective epitopes of D15 may not be conformational. However, the administration of pooled rabbit immune sera raised against the same panel of peptides failed to protect infant rats from Hib infection.

Proteolytic processing of rubella virus nonstructural proteins

The genomic RNA of rubella virus contains two long open reading frames (ORF), a 5'-proximal ORF that codes for the nonstructural proteins and a 3'-proximal ORF that encodes the structural proteins. The cDNA encoding the nonstructural protein ORF of the wild-type M33 strain of rubella virus has been obtained and sequenced. Comparison between the nonstructural proteins of the M33 and Therien strains of rubella virus revealed a 98% homology in nucleotide sequence and 98.1% in deduced amino acid sequence. To examine the processing of rubella virus nonstructural protein, the complete nonstructural protein ORF was expressed in BHK cells using a pSFV expression vector. Three nonstructural protein products (p200, p150, and p90) with molecular weights of 200, 150, and 90 kDa were identified using antisera raised against synthetic peptides corresponding to regions of the nonstructural proteins. p200 is the polyprotein precursor, while p150 and p90 are the cleavage products. Site-directed mutagenesis of the Cys-1151 residue (one of the catalytic dyad residues of the viral protease) and of the Gly-1300 residue (the viral protease cleavage site) abrogated protease activity and p200 precursor cleavage, respectively. Coexpression of mutant constructs in BHK cells indicated that rubella virus protease can function both in cis and in trans.

A rational basis for the use of combined heparin/aspirin and IVIG immunotherapy in the treatment of recurrent IVF failure associated with antiphospholipid antibodies

PROBLEMS

1) Does the administration of heparin and aspirin (H/A) in combination with intravenous immunoglobulin G (IVIG) improve in vitro fertilization (IVF) implantation and birth rates in patients with recurrent IVF failure? 2) Is the effect of such treatment related to the antiphospholipid antibody (APA) status of the patients concerned?

METHOD OF STUDY

Subjects consisted of 89 women younger than 36 years of age whose infertility was a result of causes other than male infertility and who had experienced four or more failed IVF/embryo transfer procedures. Fifty-two women were APA+ (group A), and 37 were APA- (group B). All patients, regardless of their APA status, received H/A (5000 U sq bid), aspirin (81 mg po qd) from the inception of menotropin therapy along with IVIG (20 g) through a single infusion 3 to 10 days before egg retrieval.

RESULTS

Twenty-two (42%) of group A and 7 (19%) of group B patients achieved live births (P = 0.020).

CONCLUSIONS

IVF outcome is significantly improved when H/A and IVIG are administered to APA+ women with repeat IVF failures. APA- women do not seem to benefit from such treatment.

The use of combined heparin/aspirin and immunoglobulin G therapy in the treatment of in vitro fertilization patients with antithyroid antibodies

PROBLEM

To compare the effect of heparin/aspirin therapy alone vs. heparin/aspirin in combination with intravenous immuno-globulin (IVIg) immunotherapy on in vitro fertilization (IVF) outcome of patients who test positive for antithyroid antibodies (ATAs).

METHOD OF STUDY

Eighty-two women younger than 40 years of age whose infertility was related exclusively to female causes were evaluated. All tested positive for organ-specific antithyroid antibodies (antimicrosomal and/or antithyroglobulin antibodies), but negative for antiphospholipid antibodies. Thirty-seven of these women (group A) received H/A alone, whereas 45 (group B) received heparin/aspirin in combination with IVIg.

RESULTS

Ten (27%) of women in group A and 23 (51%) of women in group B achieved live births after completion of a single IVF/embryo transfer cycle (P = 0.027).

CONCLUSION

We conclude that IVIg therapy significantly improves IVF success rates in ATA+ women.

A strategy for rational design of fully synthetic glycopeptide conjugate vaccines

The present study describes a strategy to rationally design fully synthetic glycopeptide conjugate vaccines. Glycopeptide immunogens were constructed by coupling synthetic oligosaccharides comprising repeating units of synthetic 3-beta-D-ribose-(1-1)-D-ribitol-5-phosphate (sPRP) to synthetic peptides containing potent T-helper cell determinants and B-cell epitopes of the Haemophilus influenzae type b (Hib) outer membrane proteins (OMPs) P1, P2, and P6. Rabbit immunogenicity studies revealed that some of these fully synthetic glycoconjugates were capable of eliciting high titers of both anti-PRP and anti-OMP immunoglobulin G antibodies. In addition, we systematically investigated the factors which could influence their immunogenicity. We observed that the magnitude of the anti-PRP antibody response markedly depended on the relative spatial orientation of sPRP and T-cell epitopes, the anti-PRP antibody response was enhanced when a multiple antigenic peptide was used as a carrier, the anti-PRP antibody response was optimal for three PRP repeating units, and lipidation of peptide-PRP conjugates had a minimal effect on the magnitude of the anti-PRP antibody response. The results of this study clearly demonstrate that coupling a carbohydrate hapten to a peptide can provide T-cell help and convert it into a T-cell-dependent antigen. The antisera raised against these conjugates were also found to be protective against Hib infection in the infant rat model of bacteremia.

Effect of lipid modification on the physicochemical, structural, antigenic and immunoprotective properties of Haemophilus influenzae outer membrane protein P6

The outer membrane lipoprotein, P6 of Haemophilus influenzae was studied to determine the importance of the native palmitoyl moiety on its physicochemical and immunological properties. A recombinant P6 (rP6) molecule devoid of lipidation signal sequence was expressed in Escherichia coli and its properties were compared to those of the palmitylated protein purified from H. influenzae. The isoelectric point of rP6 was more acidic than that of the native protein and also exhibited less secondary structure than P6 as judged by circular dichroism. However, both forms of P6 induced identical P6-specific antibody titers in guinea pigs when Freund's adjuvant was used. These antisera reacted with a panel of overlapping P6 peptides in a comparable manner and in addition, rabbit antisera raised against the P6 peptides reacted equally well with P6 and rP6. Furthermore, all human convalescent sera tested exhibited similar anti-P6 and anti-rP6 antibody titers. However, rP6 was less immunogenic than P6 when administered either without adjuvant or in alum and when tested in competitive inhibition studies with anti-P6 antibodies, was a less effective inhibitor than native P6, suggesting a diminution in some of the antigenic activity of rP6. In spite of these differences, rP6 was capable of eliciting a protective antibody response against live H. influenzae type b challenge in a modified infant rat model of bacteremia. These findings demonstrate that the non-fatty acylated rP6 could possibily be substituted for native P6 in a vaccine against H. influenzae.

The major outer membrane protein, CD, extracted from Moraxella (Branhamella) catarrhalis is a potential vaccine antigen that induces bactericidal antibodies

The major outer membrane protein of Moraxella (Branhamella) catarrhalis, CD, was detergent-extracted from the bacterial cell wall and purified to homogeneity in high yields by a simple process. The purified protein appeared to exhibit immunogenic properties similar to those of native CD exposed on the surface of the bacterium. Antibodies to CD raised in mice specifically bound to intact B. catarrhalis, as determined by flow cytometry analysis. The IgG subclass distributions of anti-CD antibodies in sera from mice immunized with purified CD or with B. catarrhalis were also similar. CD was found to be antigenically conserved among a panel of B. catarrhalis isolates, as demonstrated by the consistent reactivities of mouse anti-CD antisera with a common 60 kDa protein on immunoblots. Furthermore, convalescent sera collected from patients with otitis media due to B. catarrhalis infection were found to be reactive with the CD protein by immunoblotting. Finally, the purified protein induced antibodies in guinea pigs and mice that exhibited in vitro bactericidal activity against the pathogen. Therefore, the native CD outer membrane protein represents a potentially useful antigen for inclusion in a vaccine against B. catarrhalis.

Chemical synthesis of Haemophilus influenzae glycopeptide conjugates

A simple procedure for conjugating synthetic fragments of the capsular polysaccharide of Haemophilus influenzae type b, poly-3-beta-D-ribose-(1,1)-D-ribitol-5-phosphate (sPRP) to linear peptides is described. The procedure consists of (i) reacting the amino group of amino-heptyl sPRP with m-maleimidobenzoyl-N-hydroxysuccinimide (MBS) in phosphate buffer, pH 7.5; (ii) selectively coupling the MBS-modified sPRP to the sulfhydryl group of the cysteine residue of peptides containing functional T-helper cell epitope(s). The glycopeptide conjugates were purified by gel filtration chromatography, biochemically characterized, and elicited protective level of anti-PRP antibody responses in rabbits.

Host genetic and adjuvant factors influence epitope specificity to a major recombinant grass allergen

The role of host genetic and adjuvant factors in the induction of immune responses to a major recombinant Kentucky bluegrass allergen was examined utilizing five strains of mice and two different adjuvants. Analysis of the recombinant allergen-specific antibodies induced in these strains indicated that the antibodies of various isotypes were differentially regulated. In terms of IgE antibody response, BDF1 and DBA/2 were characterized as high responder, whereas BALB/C, CBA/J and C57BL/6 were intermediate and SJL was a low responder. In different strains, both dextran sulfate (DS) and complete Freund's adjuvant (CFA), as adjuvants, induced recombinant allergen-specific IgE antibodies of similar titer, however, CFA induced higher IgG2a and lower IgM antibodies compared to DS. Further, analysis of T cell proliferative responses of the splenocytes of different strains demonstrated that these strains varied also in their capacity to respond to synthetic peptides. Furthermore, utilizing a panel of synthetic peptides corresponding to the recombinant allergen, we demonstrated that the antibodies induced by the recombinant allergen with CFA in different strains vary with respect to their epitope specificity. In the BDF1 strain, compared to DS, CFA as adjuvant induced recombinant allergen-specific antibodies of additional peptide specificity. Taken together, these results suggest that both host genetic background and adjuvants govern the fine specificity of antibodies produced against this recombinant Kentucky bluegrass allergen.

The insulin-mimetic agent vanadate promotes receptor endocytosis and inhibits intracellular ligand-receptor degradation by a mechanism distinct from the lysosomotropic agents

Vanadate (sodium orthovanadate) is an insulin-mimetic agent and phosphotyrosine phosphatase inhibitor that has been proposed as a potential therapeutic agent for diabetes. We previously reported that vanadate decreased the number of cell-surface insulin receptors but inhibited receptor degradation in cultured lymphocytes (IM-9) (1). To determine whether vanadate affected receptors without intrinsic tyrosine kinase activity, its effects on LDL and transferrin receptors and their ligands were examined. Vanadate exposure resulted in a dose- and time-dependent decrease in LDL binding to cultured human fibroblasts associated with a decrease in cell surface receptor number while total solubilized cell LDL receptors increased. Vanadate also inhibited the LDL-mediated downregulation of total cellular LDL receptors in the absence and presence of cycloheximide consistent with an inhibition of LDL receptor degradation. In the case of the ligand, vanadate augmented the accumulation of intact 125I-LDL associated with an inhibition of up to 80% of the ability of LDL to decrease cholesterol synthesis. Since these actions were similar to the effects of lysosomotropic agents, we examined the effect of vanadate on intraendosomal pH using the fluorescent probe acridine orange. In contrast with chloroquine and NH4Cl, vanadate did not neutralize the pH of the acidic intracellular compartment. Furthermore, after a transient insulin-like effect, chronic exposure to vanadate diminished 125I-diferric transferrin binding to rat adipocytes. In contrast with the inhibitory action of NH4Cl, intracellular 59Fe uptake remained unaffected and was proportional to cell-surface binding capacity in the presence of vanadate. These data demonstrate a chronic effect of vanadate to promote the accumulation of intracellular receptors and to inhibit ligand and receptor degradation. The latter effect is not mediated by pH changes, appears to be localized to a late endosomal/lysosomal compartment, and suggests a possible role for tyrosine dephosphorylation in the regulation of receptor-ligand degradation.