A rapid and non-invasive proteomic analysis using DBS and buccal swab for multiplexed second-tier screening of Pompe disease and Mucopolysaccharidosis type I

PURPOSE

Current newborn screening programs for Pompe disease (PD) and mucopolysaccharidosis type I (MPS I) suffer from a high false positive rate and long turnaround time for clinical follow up. This study aimed to develop a novel proteomics-based assay for rapid and accurate second-tier screening of PD and MPS I. A fast turnaround assay would enable the identification of severe cases who need immediate clinical follow up and treatment.

METHODS

We developed an immunocapture coupled with mass spectrometry-based proteomics (Immuno-SRM) assay to quantify GAA and IDUA proteins in dried blood spots (DBS) and buccal swabs. Sensitivity, linearity, reproducibility, and protein concentration range in healthy control samples were determined. Clinical performance was evaluated in known PD and MPS I patients as well as pseudodeficiency and carrier cases.

RESULTS

Using three 3.2 mm punches (~13.1 μL of blood) of DBS, the assay showed reproducible and sensitive quantification of GAA and IDUA. Both proteins can also be quantified in buccal swabs with high reproducibility and sensitivity. Infantile onset Pompe disease (IOPD) and severe MPS I cases are readily identifiable due to the absence of GAA and IDUA, respectively. In addition, late onset Pompe disease (LOPD) and attenuated MPS I patients showed much reduced levels of the target protein. By contrast, pseudodeficiency and carrier cases exhibited significant higher target protein levels compared to true patients.

CONCLUSION

Direct quantification of endogenous GAA and IDUA peptides in DBS by Immuno-SRM can be used for second-tier screening to rapidly identify severe PD and MPS I patients with a turnaround time of <1 week. Such patients could benefit from immediate clinical follow up and possibly earlier treatment.

Interprofessional collaboration among first responder students in a simulated disaster exercise

INTRODUCTION

Interprofessional disaster simulation exercises provide an opportunity for first responder students to learn about disaster response and recovery, to practice their roles and to learn to collaborate with other first responders. With the move to virtual education during the COVID-19 pandemic, a table-top disaster exercise is an alternative format to inperson exercises. To date, most disaster simulation exercises for students have focused on the roles of healthcare providers. As first responders play a critical role in disaster management, there is a need for interprofessional exercises that include students in first responder programs.

METHODS

A table-top disaster simulation exercise was held with students from the police (n = 94) and firefighter (n = 30) programs at a large community college in Toronto, Canada, in February 2021. It was held virtually using the Zoom® platform, with college faculty as well as professionals from community partner sites. An evaluation survey that had open- and closed-ended items was administered to students following the event.

RESULTS

Thirty-eight percent of the students participated in the survey, and the majority rated the event highly useful and reported that the exercise demonstrated the importance of interprofessional collaboration. Students' responses to the open-ended survey items yielded two themes: understanding roles and performing under duress.

DISCUSSION

This evaluation demonstrates the value of using a simulated disaster exercise to teach first responder students about their role in disaster response and recovery, and the importance of interprofessional collaboration.

Direct Measurement of ATP7B Peptides Is Highly Effective in the Diagnosis of Wilson Disease

BACKGROUND & AIMS

Both existing clinical criteria and genetic testing have significant limitations for the diagnosis of Wilson disease (WD), often creating ambiguities in patient identification and leading to delayed diagnosis and ineffective management. ATP7B protein concentration, indicated by direct measurement of surrogate peptides from patient dried blood spot samples, could provide primary evidence of WD. ATP7B concentrations were measured in patient samples from diverse backgrounds, diagnostic potential is determined, and results are compared with biochemical and genetic results from individual patients.

METHODS

Two hundred and sixty-four samples from biorepositories at 3 international and 2 domestic academic centers and 150 normal controls were obtained after Institutional Review Board approval. Genetically or clinically confirmed WD patients with a Leipzig score >3 and obligate heterozygote (carriers) from affected family members were included. ATP7B peptide measurements were made by immunoaffinity enrichment mass spectrometry.

RESULTS

Two ATP7B peptides were used to measure ATP7B protein concentration. Receiver operating characteristics curve analysis generates an area under the curve of 0.98. ATP7B peptide analysis of the sequence ATP7B 887 was found to have a sensitivity of 91.2%, specificity of 98.1%, positive predictive value of 98.0%, and a negative predictive value of 91.5%. In patients with normal ceruloplasmin concentrations (>20 mg/dL), 14 of 16 (87.5%) were ATP7B-deficient. In patients without clear genetic results, 94% were ATP7B-deficient.

CONCLUSIONS

Quantification of ATP7B peptide effectively identified WD patients in 92.1% of presented cases and reduced ambiguities resulting from ceruloplasmin and genetic analysis. Clarity is brought to patients with ambiguous genetic results, significantly aiding in noninvasive diagnosis. A proposed diagnostic score and algorithm incorporating ATP7B peptide concentrations can be rapidly diagnostic and supplemental to current Leipzig scoring systems.

A Systematic Review of Motivational Interviewing to Address Substance Use with Justice-Involved Adults

Motivational Interviewing (MI) is widely used in substance abuse treatment, possibly due to the short sessions and the treatment's cost-effectiveness. Previous research has established the efficacy of MI among a broad range of populations and outcomes. However, there is a lack of a review of the knowledge about if MI works with justice-involved individuals who have substance use issues. Purpose: This review aimed to examine the extent of the literature on MI as a treatment to decrease rates of substance use for justice-involved individuals. Methods: The databases utilized for the review include Academic Search Complete (EBSCO), PsycINFO, and ProQuest. The dates for the literature inclusion were from 2008 to March 2020. The literature search was initiated in February and was completed in March 2020. Results: Five RCT studies were identified. Studies were conducted using populations during incarceration in prison, prior to release from jail, through probation, and those with DWI charges. However, all of the populations included were actively being monitored for substance use. All five studies found no difference between groups at the latest point in the study, which for most included the follow-up measure. Consideration for potential moderators such as severity and type of substance use, and length of treatment and follow up data are discussed. Conclusion: The results of the review indicated that more standardized and rigorous research is needed for exploring MI with individuals involved with the justice system with the focus of decreasing substance use.

'TB or not TB': the conundrum of pre-European contact tuberculosis in the Pacific

Tuberculosis (TB) is a major global health threat, infecting one-third of the world's population. Despite this prominence, the age, origin and spread of the disease have been topics of contentious debate. Molecular studies suggest that Mycobacterium tuberculosis 'sensu stricto', the most common strain of TB infecting humans today, originated in Africa and from there spread into Europe and Asia. The M. tuberculosis strains most commonly found across the Pacific and the Americas today are most closely related to European strains, supporting a hypothesis that the disease only reached these regions relatively recently via European sailors or settlers. However, this hypothesis is inconsistent with palaeopathological evidence of TB-like lesions in human remains from across the Pacific that predate European contact. Similarly, genetic evidence from pre-European South American mummies challenges the notion of a European introduction of the disease into the Pacific. Here, we review the complex evidence for the age and origin of TB in the Pacific, and discuss key gaps in our knowledge and how these may be addressed. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

p.P1379S, a benign variant with reduced ATP7B protein level in Wilson Disease

BACKGROUND

Wilson disease (WD) is an autosomal recessive disorder of copper transport caused by inherited defects in the ATP7B gene and results in toxic accumulation of copper in various organs. We previously reported a family with three consecutive generations affected by WD that carries the variant, p.P1379S, which was classified at the time as likely pathogenic. However, recent investigations of the p.P1379S variant indicate a possible conflict of interpretations regarding its pathogenicity. This led us to explore the quantification of ATP7B in dried blood spots (DBS) using a surrogate peptide to study the effects of the p.P1379S variant on ATP7B concentrations in two unrelated families with the common p.P1379S variant.

METHODS AND RESULTS

ATP7B was quantified using the peptide immunoaffinity enrichment coupled with selected reaction monitoring mass spectrometry (immuno-SRM) method which utilizes antibody-mediated peptide capture from DBS. Two patients affected with WD had undetectable ATP7B level while four compound heterozygous children with one known pathogenic variant and the p.P1379S had significantly reduced ATP7B levels. Of note, all four children remain asymptomatic without abnormal laboratory consequences despite being untreated for WD.

CONCLUSION

These two families demonstrated that p.P1379S, when compounded with two known pathogenic variants, resulted in significantly reduced protein levels but retained enough function to maintain normal copper homeostasis. This implies that p.P1379S is benign in nature. A better understanding of the nature and consequences of variants in WD will help in informing patient care and avoiding unnecessary treatments.

Multiplexed Proteomic Analysis for Diagnosis and Screening of Five Primary Immunodeficiency Disorders From Dried Blood Spots

Early detection of Primary Immunodeficiencies Disorders (PIDDs) is of paramount importance for effective treatment and disease management. Many PIDDs would be strong candidates for newborn screening (NBS) if robust screening methods could identify patients from dried blood spots (DBS) during the neonatal period. As majority of congenital PIDDs result in the reduction or absence of specific proteins, direct quantification of these target proteins represents an attractive potential screening tool. Unfortunately, detection is often limited by the extremely low protein concentrations in blood cells and limited blood volume present in DBS. We have recently developed a robust novel method for quantification of low abundance proteins in DBS for PIDDs using peptide immunoaffinity enrichment coupled to selected reaction monitoring (immuno-SRM). Here, we further generated a multiplexed Immuno-SRM panel for simultaneous screening of eight signature peptides representing five PIDD-specific and two cell-type specific proteins from DBS. In samples from 28 PIDD patients including two carriers, representing X-Linked Agammaglobulinemia (XLA), Wiskott-Aldrich Syndrome (WAS), X-Linked Chronic Granulomatous Disease (XL-CGD), DOCK8 Deficiency and ADA deficiency, peptides representing each disease are significantly reduced relative to normal controls and patient identification had excellent agreement with clinical and molecular diagnosis. Also included in the multiplex panel are cell specific markers for platelets (CD42) and Natural Killer Cells (CD56). In patients with WAS, CD42 levels were found to be significantly reduced consistent with characteristic thrombocytopenia. A patient with WAS analyzed before and after bone marrow transplant showed normalized WAS protein and platelet CD42 after treatment highlighting the ability of immuno-SRM to monitor the effects of PIDD treatment. The assay was readily reproduced in two separate laboratories with similar analytical performance and complete agreement in patient diagnosis demonstrating the effective standardized methods. A high-throughput Immuno-SRM method screens PIDD-specific peptides in a 2.5-min runtime meeting high volume NBS workflow requirements was also demonstrated in this report. This high-throughput method returned identical results to the standard Immuno-SRM PIDD panel. Immuno-SRM peptide analysis represents a robust potential clinical diagnostic for identifying and studying PIDD patients from easily collected and shipped DBS and supports a significant potential for early PIDD diagnosis through newborn screening.

The co-occurrence of Wilson disease and X-linked agammaglobulinemia in one family highlights the promising diagnostic potential of proteolytic analysis

BACKGROUND

We report the first case of a family with co-occurrence of Wilson disease (WD), an autosomal recessive disorder of copper metabolism, and X-linked agammaglobulinemia (XLA), a primary immunodeficiency disorder (PIDD) that features marked reduction in circulating B lymphocytes and serum immunoglobulins.

METHODS AND RESULTS

Through utilization of a multiplexed biomarker peptide quantification method known as the immuno-SRM assay, we were able to simultaneously and independently identify which family members are affected with WD and which are affected with XLA using dried blood spots (DBS).

CONCLUSION

Being able to delineate multiple diagnoses using proteolytic analysis from a single DBS provides support for implementation of this methodology for clinical diagnostic use as well as large-scale population screening, such as newborn screening (NBS). This could allow for early identification and treatment of affected individuals with WD or XLA, which have been shown to reduce morbidity and decrease mortality in these two populations.

Rapid Multiplexed Proteomic Screening for Primary Immunodeficiency Disorders From Dried Blood Spots

Background: Primary immunodeficiency disorders (PIDD) comprise a group of life-threatening congenital diseases characterized by absent or impaired immune responses. Despite the fact that effective, curative treatments are available with optimal clinical outcomes when diagnosed early, newborn screening does not exist for the majority of these diseases due to the lack of detectable, specific biomarkers or validated methods for population-based screening. Peptide immunoaffinity enrichment coupled with selected reaction monitoring mass spectrometry (immuno-SRM) is a sensitive proteomic assay, involving antibody-mediated peptide capture, that allows for concurrent quantification of multiple analytes. This assay has promise for use in potential newborn screening of PIDDs that lead to diminished or absent target proteins in the majority of cases. Objective: To determine and evaluate if a multiplex assay based on immuno-SRM is able to reliably and precisely distinguish affected patients with X-linked agammaglobulinemia (XLA), Wiskott-Aldrich Syndrome (WAS), and CD3ϵ-associated severe combined immunodeficiency (SCID) from one another and from unaffected normal control dried blood spot (DBS) samples. Methods: We performed a blinded, multiplexed analysis of proteolytically-generated peptides from WASp, BTK, and CD3ϵ (for WAS, XLA, and SCID, respectively) in DBS samples from 42 PIDD patients, 40 normal adult controls, and 62 normal newborns. The peptide ATPase copper transporting protein (ATP7B) 1056 was simultaneously monitored for quality assurance purposes. Results: The immuno-SRM assays reliably quantified the target peptides in DBS and accurately distinguished affected patients from normal controls. Analysis of signature peptides found statistically significant reduction or absence of peptide levels in affected patients compared to control groups in each case (WASp and BTK: p = 0.0001, SCID: p = 0.05). Intra and inter-assay precision ranged from 11 to 22% and 11 to 43% respectively; linearity (1.39-2000 fmol peptide), and stability (≤ 0.09% difference in 72 h) showed high precision for the multiplexed assay. Inter-laboratory assay comparison showed high concordance for measured peptide concentrations, with R² linearity ≥ 0.97 for the WASp 274, CD3ϵ 197, BTK 407, and ATP7B 1056 peptides. Conclusion: Immuno-SRM-based quantification of proteotypic peptides from WASp, BTK, and CD3ϵ in DBS distinguishes relevant PIDD cases from one another and from controls, raising the possibility of employing this approach for large-scale multiplexed newborn screening of selective PIDDs.

Gd3+:DOTA-Modified 2-Hydroxypropyl-β-Cyclodextrin/4-Sulfobutyl Ether-β-Cyclodextrin-Based Polyrotaxanes as Long Circulating High Relaxivity MRI Contrast Agents

A family of five water-soluble Gd³⁺:1,4,7,10-tetraazacyclododecane-1,4,7-tetraacetic acid-modified polyrotaxane (PR) magnetic resonance contrast agents bearing mixtures of 2-hydroxypropyl-β-cyclodextrin and 4-sulfobutylether-β-cyclodextrin macrocycles threaded onto Pluronic cores were developed as long circulating magnetic resonance contrast agents. Short diethylene glycol diamine spacers were utilized for linking the macrocyclic chelator to the PR scaffold prior to Gd³⁺ chelation. The PR products were characterized by ¹H NMR, gel permeation chromatography/multiangle light scattering, dynamic light scattering, and analytical ultracentrifugation. Nuclear magnetic relaxation dispersion and molar relaxivity measurements at 23 °C revealed that all the PR contrast agents displayed high spin-spin T₁ relaxation and spin-lattice T₂ relaxation rates relative to a DOTAREM control. When injected at 0.05 mmol Gd/kg body weight in BALB/c mice, the PR contrast agents increased the T₁-weighted MR image intensities with longer circulation times in the blood pool than DOTAREM. Excretion of the agents occurred predominantly via the renal or biliary routes depending on the polyrotaxane structure, with the longest circulating L81 Pluronic-based agent showing the highest liver uptake. Proteomic analysis of PR bearing different β-cyclodextrin moieties indicated that lipoproteins were the predominant component associated with these materials after serum exposure, comprising as much as 40% of the total protein corona. We infer from these findings that Gd(III)-modified PR contrast agents are promising long-circulating candidates for blood pool analysis by MRI.

Complex history of dog (Canis familiaris) origins and translocations in the Pacific revealed by ancient mitogenomes

Archaeological evidence suggests that dogs were introduced to the islands of Oceania via Island Southeast Asia around 3,300 years ago, and reached the eastern islands of Polynesia by the fourteenth century AD. This dispersal is intimately tied to human expansion, but the involvement of dogs in Pacific migrations is not well understood. Our analyses of seven new complete ancient mitogenomes and five partial mtDNA sequences from archaeological dog specimens from Mainland and Island Southeast Asia and the Pacific suggests at least three dog dispersal events into the region, in addition to the introduction of dingoes to Australia. We see an early introduction of dogs to Island Southeast Asia, which does not appear to extend into the islands of Oceania. A shared haplogroup identified between Iron Age Taiwanese dogs, terminal-Lapita and post-Lapita dogs suggests that at least one dog lineage was introduced to Near Oceania by or as the result of interactions with Austronesian language speakers associated with the Lapita Cultural Complex. We did not find any evidence that these dogs were successfully transported beyond New Guinea. Finally, we identify a widespread dog clade found across the Pacific, including the islands of Polynesia, which likely suggests a post-Lapita dog introduction from southern Island Southeast Asia.

Pluronic based β-cyclodextrin polyrotaxanes for treatment of Niemann-Pick Type C disease

Niemann-Pick Type C disease (NPC) is a rare metabolic disorder characterized by disruption of normal cholesterol trafficking within the cells of the body. There are no FDA approved treatments available for NPC patients. Recently, the cycloheptaglucoside 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) has shown efficacy as a potential NPC therapeutic by extending lifetime in NPC mice, delaying neurodegeneration, and decreasing visceral and neurological cholesterol burden. Although promising, systemic HP-β-CD treatment is limited by a pharmacokinetic profile characterized by rapid loss through renal filtration. To address these shortcomings, we sought to design a family of HP-β-CD pro-drug delivery vehicles, known as polyrotaxanes (PR), capable of increasing the efficacy of a given injected dose by improving both pharmacokinetic profile and bioavailability of the HP-β-CD agent. PR can effectively diminish the cholesterol pool within the liver, spleen, and kidney at molar concentrations 10-to-100-fold lower than monomeric HP-β-CD. In addition to this proof-of-concept, use of PR scaffolds with differing physiochemical properties reveal structure-activity relationships in which PR characteristics, including hydrophobicity, threading efficiency and surface charge, were found to both decisively and subtly effect therapeutic efficacy. PR scaffolds exhibit absorption, pharmacokinetics, and biodistribution patterns that are significantly altered from monomeric HP-β-CD. In all, PR scaffolds hold great promise as potential treatments for visceral disease in NPC patients.

PLGA-PEG nano-delivery system for epigenetic therapy

Efficient delivery of cytidine analogues such as Azacitidine (AZA) into solid tumors constitutes a primary challenge in epigenetic therapies. We developed a di-block nano-vector based on poly(lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) for stabilization of the conjugated AZA under physiological conditions. With equimolar drug content, our nano-conjugate could elicit a better anti-proliferative effect over free drug in breast cancer both in vitro and in vivo, through reactivation of p21 and BRCA1 to restrict cell proliferation. In addition, we applied single-molecule fluorescence tools to characterize the intracellular behavior of the AZA-PLGE-PEG nano-micelles at a finer spatiotemporal resolution. Our results suggest that the nano-micelles could effectively enrich in cancer cells and may not be limited by nucleoside transporters. Afterwards, the internalized nano-micelles exhibit pH-dependent release and resistance to active efflux. Altogether, our work describes a delivery strategy for DNA demethylating agents with nanoscale tunability, providing a cost-effective option for pharmaceutics.

Human resource management and unit performance in knowledge-intensive work

To clarify the potential value of a targeted system of human resource (HR) practices, we explore the unique effects of a relationship-oriented HR system and the more commonly studied high commitment HR system on unit performance in the context of knowledge-intensive work. We develop theoretical arguments suggesting that the high commitment HR system contributes to unit performance through its positive effects on employees' collective organizational commitment, general and firm-specific human capital, and access to knowledge. We argue that the relationship-oriented HR system contributes to unit performance through its positive effects on employees' collective access to knowledge by fostering a social context and interpersonal exchange conditions which support employees' ongoing access to knowledge flows within and outside their unit and broader organization. Based on unit-level data collected from a matched sample of employees and managers in 128 units in the science and engineering division of a large hydroelectric power organization, our results suggest that the targeted, relationship-oriented HR system is related to firm performance and may complement a broader, high commitment approach to managing knowledge workers. Specifically, the positive relationship between the high commitment HR system and unit performance is mediated by employees' collective organizational commitment, firm-specific human capital, and access to knowledge in other organizational units; whereas the positive relationship between the relationship-oriented HR system and unit performance is mediated by units' access to knowledge within the unit, in other units, and outside the organization. (PsycINFO Database Record

A cryogenic optical feedthrough using polarization maintaining fibers

Polarization maintaining optical fibers can be used to transmit linearly polarized light over long distances but their use in cryogenic environments has been limited by their sensitivity to temperature changes and associated mechanical stress. We investigate experimentally how thermal stresses affect the polarization maintaining fibers and model the observations with Jones matrices. We describe the design, construction, and testing of a feedthrough and fiber termination assembly that uses polarization maintaining fiber to transmit light from a 633 nm HeNe laser at room temperature to a homodyne polarization-based interferometer in a cryogenic vacuum. We report on the efficiency of the polarization maintaining properties of the feedthrough assembly. We also report that, at cryogenic temperatures, the interferometer can achieve a sensitivity of 8 × 10(-10) rad/√Hz at 0.05 Hz using this feedthrough.

Microfluidic Assembly of Cationic-β-Cyclodextrin:Hyaluronic Acid-Adamantane Host:Guest pDNA Nanoparticles

Traditionally, transfection complexes are typically formed by bulk mixing, producing particles with high polydispersity and limited control over vector size. Herein, we demonstrate the use of a commercial micro-reactor to assemble pDNA:cationic cyclodextrin:pendant polymer nanoparticles using a layer-by-layer approach. Our studies reveal that the particles formulated via microfluidic assembly have much smaller sizes, lower polydispersity, lower ζ-potentials, and comparable cell viability and transfection profiles in HeLa cells than bulk mixed particles. The complexes also show a flow rate-dependent stability, with particles formed at slower flow rates giving rise to more stable complexes as determined by heparin challenge. Our findings suggest that microfluidic reactors offer an attractive method for assembling reproducible, size-controlled complexes from multi-component transfection complex assemblies.

Synthesis, characterization, and evaluation of pluronic-based β-cyclodextrin polyrotaxanes for mobilization of accumulated cholesterol from Niemann-Pick type C fibroblasts

Several lines of evidence suggest that β-cyclodextrin (β-CD) derivatives initiate the efflux of accumulated, unesterified cholesterol from the late endosomal/lysosomal compartment in Niemann Pick C (NPC) disease models. Unfortunately, repeated injections or continuous infusions of current β-CD therapies are required to sustain suppression of symptoms and prolong life. In an effort to make CD treatment a more viable option by boosting efficacy and improving pharmacokinetics, a library of Pluronic surfactant-based β-CD polyrotaxanes has been developed using biocompatible poly(ethylene glycol) (PEG)-polypropylene glycol (PPG)-PEG triblock copolymers. These compounds carry multiple copies of β-CD as shown by (1)H NMR, 2D nuclear Overhouser effect spectroscopy, gel permeation chromatography/multiangle light scattering, analytical ultracentrifugation analysis, matrix assisted laser desorption/ionization mass spectrometry, and diffusion-ordered spectroscopy. Analyses of free β-cyclodextrin contamination in the compounds were made by reverse phase high pressure liquid chromatography and hydrophilic interaction liquid chromatography. Dethreading kinetics were studied by reverse phase high pressure liquid chromatography, UV/vis, and (1)H NMR analysis. Filipin staining studies using npc2(-/-) fibroblasts show significant reversal of cholesterol accumulation after treatment with polyrotaxane compounds. The rate and efficacy of reversal is similar to that achieved by equivalent amounts of monomeric β-CD alone.

The role of topical antibiotics used as prophylaxis in surgical site infection prevention

Compared with systemic antibiotic therapy, the topical or local delivery of an antibiotic has many potential advantages. However, local antibiotics at the surgical site have received very limited approval in any of the surgical prophylaxis consensus guidelines that we are aware of. A review of the literature was carried out through searches of peer-reviewed publications in PubMed in the English language over a 30 year period between January 1980 and May 2010. Both retrospective and prospective studies were included, as well as meta-analyses. With regard to defining 'topical' or 'local' antibiotic application, the application of an antibiotic solution to the surgical site intraoperatively or immediately post-operatively was included. A number of surgical procedures have been shown to significantly benefit from perioperative topical prophylaxis, e.g. joint arthroplasty, cataract surgery and, possibly, breast augmentation. In obese patients undergoing abdominal surgery, topical surgical prophylaxis is also proven to be beneficial. The selective use of topical antibiotics as surgical prophylaxis is justified for specific procedures, such as joint arthroplasty, cataract surgery and, possibly, breast augmentation. In selective cases, such as obese patients undergoing abdominal surgery, topical surgical prophylaxis is also proven to be beneficial. Apart from these specific indications, the evidence for use of topical antibiotics in surgery is lacking in conclusive randomized controlled trials.

Cost-effectiveness of employing a total parenteral nutrition surveillance nurse for the prevention of catheter-related bloodstream infections

The cost of catheter-related bloodstream infection (CRBSI) is substantial in terms of morbidity, mortality and financial resources. Total parenteral nutrition (TPN) is a recognised risk factor for CRBSI. In 1997, an intravenous nutrition nurse was promoted to TPN surveillance clinical nurse manager (CNM) and quarterly infection audit meetings were introduced to monitor trends in CRBSI. Data were prospectively collected over a 15-year period using specific TPN records in a 535-bed tertiary acute university hospital. A total of 20 439 CVC-days and 307 CRBSIs were recorded. Mean number of infections before, and after, the introduction of a dedicated TPN surveillance CNM were compared. Mean CRBSI per 1000 catheter-days+/-SD was 20.5+/-6.34 prior to 1997 and 14.64+/-7.81 after 1997, representing a mean reduction of 5.84 CRBSIs per 1000 catheter-days (95% CI: -4.92 to 16.60; P=0.05). Mean number of CRBSIs per year+/-SD was 28.3+/-4.93 prior to 1997 and 18.5+/-7.37 after 1997, representing a mean decrease of 9.8 infections per year (95% CI: 0.01 to 19.66; P<0.05). The savings made by preventing 9.8 infections per year were calculated from data on bed-days obtained from the hospital finance office. The cost in hospital days saved per annum was euro135,000. Introduction of a TPN surveillance CNM saved the hospital at least euro78,300 per annum and led to a significant decrease in CRBSIs in TPN patients.

Association of Inhalation Toxicologists (AIT) working party recommendation for standard delivered dose calculation and expression in non-clinical aerosol inhalation toxicology studies with pharmaceuticals

There are many ways in which the dose can be expressed in inhalation toxicology studies. This can lead to confusion when comparing results from studies performed in different laboratories. A working party of the Association of Inhalation Toxicologists has reviewed this subject in detail and has collected data from 10 inhalation laboratories and used these data to determine a new algorithm for the calculation of Respiratory Minute Volume (RMV), one of the most important factors in the calculation of delivered dose. The recommendations of the working party for regulatory inhalation toxicology studies with pharmaceuticals are as follows: 1. The dose should be reported as the delivered dose calculated according to the formula: DD = C x RMV x D(xIF)/BW, where DD = delivered dose (mg/Kg); C = concentration of substance in air (mg/L); RMV =respiratory minute volume or the volume of air inhaled in one minute (L/min); D = duration of exposure (min); IF = proportion by weight of particles that are inhalable by the test species, the inhalable fraction (inclusion of this parameter is not essential provided that the aerosol has reasonable respirability for the intended species. If it is included, the way in which it is determined should be clearly stated); BW = bodyweight (Kg). 2. The RMV for mice, rats, dogs and cynomolgus monkeys should be calculated according to the formula:RMV(L/min) = 0.608 x BW(Kg)(0.852). 3. If deposited dose or the amount of material actually retained inthe respiratory tract is presented as supplementary information,the way in which it is calculated should be clearly stated.4. Dose should always be presented in mg/Kg but may also bepresented in other ways, such as mg/unit body surface area, as supplementary information.

Solvent and Temperature Effects on the Reduction and Amination Reactions of Electrophiles by Lithium Dialkylaminoborohydrides

The influence of temperature and solvent effects on the reduction and amination mechanisms of iodomethane by lithium N,N-diisopropylaminoborohydride (iPr-LAB) was examined in varying concentrations of THF and dioxane. The reactions of benzyl chloride and trimethylsilyl chloride with iPr-LAB in THF were also studied. The amination of iodomethane is favored over reduction at low and room temperatures in pure THF and with increasing the amount of dioxane in THF. At higher temperatures, the reduction reaction appears to compete with the amination. In dioxane solvent, however, iodomethane yields exclusively the amination product regardless of temperature. On the other hand, reduction by iPr-LAB to the aminoborane is the only product observed in THF when benzyl chloride and trimethylsilyl chloride are used. To understand the solvent effects on the product distribution, ab initio and density functional theory (DFT) calculations were used to examine the mechanisms of reduction and amination of chloromethane and bromomethane by lithium dimethylaminoborohydride (LAB) in THF and dioxane. The results of these calculations show that the relative reaction barrier heights are significantly affected by the nature of the coordinated solvent molecule and thus lend support to the experimental observations.

The interactive effects of recruitment practices and product awareness on job seekers' employer knowledge and application behaviors

In this article, the author draws on research from the literature on marketing and recruitment to identify how recruitment practices and company product awareness are related to job seekers' application behaviors through 3 aspects of job seekers' employer knowledge. Based on results from a within-subject design with data from 123 recruiting companies and 456 student job seekers, the author's findings suggest that the relationships between recruitment strategies and application intentions and decisions are moderated by product awareness. Specifically, low-information recruitment practices are significantly and positively related to application behaviors through employer familiarity and employer reputation when product awareness is low. In contrast, high-information recruitment practices are related to job seekers' application behaviors through employer reputation and job information when product awareness is high.

Isotopically labeled crosslinking reagents: resolution of mass degeneracy in the identification of crosslinked peptides

Mass spectrometry in three dimensions (MS3D) is a newly developed method for the determination of protein structures involving intramolecular chemical crosslinking of proteins, proteolytic digestion of the resulting adducts, identification of crosslinks by mass spectrometry (MS), peak assignment using theoretical mass lists, and computational reduction of crosslinks to a structure by distance geometry methods. To facilitate the unambiguous identification of crosslinked peptides from proteolytic digestion mixtures of crosslinked proteins by MS, we introduced double 18O isotopic labels into the crosslinking reagent to provide the crosslinked peptides with a characteristic isotope pattern. The presence of doublets separated by 4 Da in the mass spectra of these materials allowed ready discrimination between crosslinked and modified peptides, and uncrosslinked peptides using automated intelligent data acquisition (IDA) of MS/MS data. This should allow ready automation of the method for application to whole expressible proteomes.

The relationship between early recruitment-related activities and the application decisions of new labor-market entrants: a brand equity approach to recruitment

Theory and research from the marketing literature on customer-based brand equity were used to predict how positive exposure to 4 early recruitment-related activities-publicity, sponsorships, word-of-mouth endorsements, and advertising-may affect the application decisions of engineering students. Similar to prior marketing findings, the results suggested that early recruitment-related activities were indirectly related to intentions and decisions through 2 dimensions of employer brand image: general attitudes toward the company and perceived job attributes. The relationships between word-of-mouth endorsements and the 2 dimensions of brand image were particularly strong. In addition, it was found that early recruitment-related activities interacted with one another such that employer brand image was stronger when firms used publicity in conjunction with other early recruitment-related activities.

Prolonged ex vivo culture of cord blood CD34(+) cells facilitates myeloid and megakaryocytic engraftment in the non-obese diabetic severe combined immunodeficient mouse model

A clinical goal for ex vivo expansion of cord blood (CB) CD34(+) cells is to shorten the period of neutropenia and thrombocytopenia following myeloablative therapy and transplantation. Prolongation of cytokine expansion leads to the production of greater numbers of cells, and should have an impact on neutrophil and platelet recovery. Furthermore, expansion of CD34(+) cells should support the continued production of neutrophils and platelets in the 6-week period following transplantation. We tested these hypotheses by characterization of the kinetics (human CD45(+) cells in the blood) and phenotype (CD45, CD34, CD61, CD33, CD19 and CD3) of human engraftment in the non-obese diabetic severe combined immunodeficient mouse (NOD-SCID) following 7 or 14 d of ex vivo expansion of CB CD34(+) cells. Mice transplanted with 14 d cells showed greater percentages of human CD45(+) cells in the blood, bone marrow and spleen than mice transplanted with unexpanded cells or 7 d cells. Prolonging cytokine exposure of CD34(+) cells and transplantation with increasing numbers of input cells facilitated the production of absolute numbers of CD34(+), CD33(+), CD61(+) and CD19(+) cells in vivo. Furthermore, analysis of SCID engrafting potential showed that prolongation of culture duration facilitates in vivo expansion of CD45(+), CD34(+) and CD19(+) cells after transplantation. It is anticipated that prolonged (2 weeks) ex vivo culture of CB will have a beneficial clinical effect.

Aminoborohydrides. 12. Novel tandem S(N)Ar amination-reduction reactions of 2-halobenzonitriles with lithium N,N-dialkylaminoborohydrides

A novel tandem amination-reduction reaction has been developed in which 2-(N,N-dialkylamino)benzylamines are generated from 2-halobenzonitriles and lithium N,N-dialkylaminoborohydride (LAB) reagents. These reactions are believed to occur through a tandem S(N)Ar amination-reduction mechanism wherein the LAB reagent promotes halide displacement by the N,N-dialkylamino group, and the nitrile is subsequently reduced. This one-pot procedure is complimentary to existing synthetic methods and is an attractive synthetic tool for the nucleophilic aromatic substitution of halobenzenes with less nucleophilic amines. The (N,N-dialkylamino)benzylamine products of this reaction are easily isolated after a simple aqueous workup procedure in very good to excellent yields.

Prior cryopreservation of ex vivo-expanded cord blood cells is not detrimental to engraftment as measured in the NOD-SCID mouse model

Cytokine-mediated expansion has been proposed and successfully used to facilitate engraftment post transplantation. This study examined whether cryopreservation following expansion has a detrimental effect on the ability of cells to engraft, using the NOD-SCID mouse model. Cord blood (CB) CD34(+) cells were incubated for 7 days with stem cell factor (SCF), flt-3 ligand (FL), and megakaryocyte growth and development factor (MGDF). Expanded CD34(+) cells were transplanted into NOD-SCID mice either fresh or following cryopreservation and thawing. After thawing, recovery of nucleated cells was 94%, of CD34 cells was 63%, and of day-14 progenitors was 17%. The loss of day-14 progenitor cells among the thawed expanded cells did not influence the kinetics of human engraftment in the mouse. Bone marrow (BM) of mice transplanted with thawed expanded CD34(+) cells (14 +/- 3.9%) showed significantly higher levels of human engraftment than mice transplanted with fresh expanded CD34(+) cells (1.5 +/- 0.5%, p = 0.0064). Thawed expanded CD34(+) cells had significantly higher SCID Engrafting Potential (SEP) than freshly expanded CD34(+) cells (p < 0.001). Results suggest that prior cryopreservation does not prevent expanded cells engrafting in NOD-SCID mice.

Conditions that enable human hematopoietic stem cell engraftment in all NOD-SCID mice

BACKGROUND

Transplantation of human hematopoietic stem cells is the only true test of their long-term repopulation potential. Models are readily available to evaluate murine hematopoietic stem cells, but few exist that allow reliable quantification of human stem cells. The non-obese diabetic-severe combined immunodeficient (NOD-SCID) mouse model enables quantification of human hematopoietic stem cells, but the conditions that permit human engraftment in all animals have yet to be defined. The aims of the project were, therefore, to describe the variables that allow human engraftment in the NOD-SCID mouse model and the techniques that accurately quantify this engraftment.

METHODS

NOD-SCID mice that had or had not received 250, 325, or 400 cGy irradiation received cord blood (CB) mononuclear or CD34+ cells i.v. or i.p. Mice were killed 6 weeks after transplantation, and the bone marrow, spleen, and thymus were harvested. Four-color flow cytometric analysis, semi-quantitative PCR, myeloid and erythroid progenitor, and stem cell assays were used to monitor human engraftment.

RESULTS

A 250 or 325 cGy and i.v. injection of CB mononuclear or CD34+ cells is required to detect multilineage human engraftment in the bone marrow, spleen, or thymus of NOD-SCID mice. Four-color flow cytometric analysis and semi-quantitative PCR enable accurate detection of 0.1% human cells. Progenitor and stem cell assays provide functional information about the engrafted cells.

CONCLUSIONS

Successful development of the NOD-SCID mouse model and techniques to assess human engraftment now allow it to be used reliably to analyze the effects of short-term cytokine exposure on the long-term repopulating capacity of CB stem cells.

Aminoborohydrides. 11. Facile Reduction of N-Alkyl Lactams to the Corresponding Amines Using Lithium Aminoborohydrides

[reaction: see text] Various five- and six-membered N-alkyl lactams were reduced to the corresponding cyclic amines using lithium N,N-dialkylaminoborohydrides (LAB). Most of the reductions were essentially complete after refluxing in THF for 2 h. The cyclic amine products were easily isolated after an aqueous workup in very good to excellent yields. It is possible to selectively reduce most functional groups, such as esters, in the presence of a lactam using LAB reagents.

Progressive bradykinesia and hypokinesia of ocular pursuit in Parkinson's disease

OBJECTIVES

Patients with Parkinson's disease characteristically have difficulty in sustaining repetitive motor actions. The purpose of this study was to establish if parkinsonian difficulty with sustaining repetitive limb movements also applies to smooth ocular pursuit and to identify any pursuit abnormalities characteristic of Parkinson's disease.

METHODS

Ocular pursuit in seven patients with moderate to severe bradykinesia predominant Parkinson's disease was compared with seven age matched controls. Predictive and non-predictive pursuit of constant velocity target ramps were examined. Subjects pursued intermittently illuminated 40(0)/s ramps sweeping to the left or right with an exposure duration of 480 ms and average interval of 1.728 s between presentations. To examine for any temporal changes in peak eye velocity, eye displacement or anticipatory smooth pursuit the 124 s duration of each record was divided into four epochs (E1, E2, E3, E4), each lasting 31 s and containing 18 ramp stimuli. Three test conditions were examined in each subject: predictive (PRD1), non-predictive (NPD), and predictive (PRD2) in that order.

RESULTS

Both patients and controls initiated appropriate anticipatory pursuit before target onset in the PRD1 and PRD2 conditions that enhanced the response compared with the NPD condition. The distinctive findings in patients with Parkinson's disease were a reduction in response magnitude compared with controls and a progressive decline of response with stimulus repetition. The deficits were explained on the basis of easy fatiguability in Parkinson's disease.

CONCLUSIONS

Ocular pursuit shows distinct anticipatory movements in Parkinson's disease but peak velocity and displacement are reduced and progressively decline with repetition as found with limb movements.

Independent control of head and gaze movements during head-free pursuit in humans

1. Head and gaze movements are usually highly co-ordinated. Here we demonstrate that under certain circumstances they can be controlled independently and we investigate the role of anticipatory activity in this process. 2. In experiment 1, subjects tracked, with head and eyes, a sinusoidally moving target. Overall, head and gaze trajectories were tightly coupled. From moment to moment, however, the trajectories could be very different and head movements were significantly more variable than gaze movements. 3. Predictive head and gaze responses can be elicited by repeated presentation of an intermittently illuminated, constant velocity target. In experiment 2 this protocol elicited a build-up of anticipatory head and gaze velocity, in opposing directions, when subjects made head movements in the opposite direction to target movement whilst maintaining gaze on target. 4. In experiment 3, head and gaze movements were completely uncoupled. Subjects followed, with head and gaze, respectively, two targets moving at different, harmonically unrelated frequencies. This was possible when both targets were visual, and also when gaze followed a visual target at one frequency whilst the head was oscillated in time with an auditory tone modulated at the second frequency. 5. We conclude that these results provide evidence of a visuomotor predictive mechanism that continuously samples visual feedback information and stores it such that it can be accessed by either the eye or the head to generate anticipatory movements. This overcomes time delays in visuomotor processing and facilitates time-sharing of motor activities, making possible the performance of two tasks simultaneously.