Explainable machine learning for the prediction and assessment of complex drought impacts

Drought is a common and costly natural disaster with broad social, economic, and environmental impacts. Machine learning (ML) has been widely applied in scientific research because of its outstanding performance on predictive tasks. However, for practical applications like disaster monitoring and assessment, the cost of the models failure, especially false negative predictions, might significantly affect society. Stakeholders are not satisfied with or do not "trust" the predictions from a so-called black box. The explainability of ML models becomes progressively crucial in studying drought and its impacts. In this work, we propose an explainable ML pipeline using the XGBoost model and SHAP model based on a comprehensive database of drought impacts in the U.S. The XGBoost models significantly outperformed the baseline models in predicting the occurrence of multi-dimensional drought impacts derived from the text-based Drought Impact Reporter, attaining an average F2 score of 0.883 at the national level and 0.942 at the state level. The interpretation of the models at the state scale indicates that the Standardized Precipitation Index (SPI) and Standardized Temperature Index (STI) contribute significantly to predicting multi-dimensional drought impacts. The time scalar, importance, and relationships of the SPI and STI vary depending on the types of drought impacts and locations. The patterns between the SPI variables and drought impacts indicated by the SHAP values reveal an expected relationship in which negative SPI values positively contribute to complex drought impacts. The explainability based on the SPI variables improves the trustworthiness of the XGBoost models. Overall, this study reveals promising results in accurately predicting complex drought impacts and rendering the relationships between the impacts and indicators more interpretable. This study also reveals the potential of utilizing explainable ML for the general social good to help stakeholders better understand the multi-dimensional drought impacts at the regional level and motivate appropriate responses.

Studying the aging of Laponite suspensions using extensional rheology

The effect of aging on the break-up dynamics of Laponite suspensions was studied in an extensional geometry. It was found that samples of increased age undergo stronger necking at the midpoint. The thinning of samples, driven purely by motion of the plates, was compared with standard shear rheology to understand how the dynamics are related to the sample properties. The Laponite suspensions exhibit a growing stress overshoot with monotonically decreasing yield strain as they age. However, it is shown that the thinning curves in extension are only a good indicator of the sample's static yield stress, being insensitive to its yield strain. These measurements suggest that following an initial linear visco-elastic regime, samples accumulate significant plastic deformations prior to the complete yielding of the sample. The implications of this for the importance of assessing changes to the ductile-brittle nature of samples are also discussed.

Exploring the career experiences of Australian oral health therapists in different practice settings

OBJECTIVE

To examine the reasons behind Australian oral health therapists (OHTs) pursuing different career pathways.

BASIC RESEARCH DESIGN

Qualitative study with thematic analysis within an inductive realist approach.

METHODS

A convenience sample of OHTs completed semi-structured interviews on Zoom. Participants discussed their experiences working as OHTs and commented on the future directions for the profession in Australia.

RESULTS

Participants (n=21) chose clinical practice due to excellent job availability, good remuneration, and the opportunity to use their knowledge. Many indicated that non-clinical careers helped relieve the stress and fatigue of clinical practice. Some also enjoyed the variety that non-clinical jobs brought and viewed them as a means to advance their career. Participants indicated the need to better communicate the professional role and scope of practice of the OHT profession to other healthcare providers such as dentists and the general public. Some viewed independent practice as a way to serve the community. Others did not feel that they had the knowledge and skills to do so.

CONCLUSION

These findings may help individual OHTs in career decision-making. OHTs could assume a major role in addressing oral healthcare inequality in Australia.

Slip in adhesion tests of a Kaolin clay

Adhesion tests were performed on concentrated suspensions of Kaolin clay. At low concentrations samples formed conical deposits on both the top and bottom plates with the central region narrowing to a filament before undergoing breakup. In contrast high concentration samples deformed as a cylinder before apparently fracturing into two pieces. As the concentration of the samples was increased the samples underwent quite different forms of slip which it is shown can be deduced from their respective force distance curves. The type of slip behaviour for a given concentration of clay could be modified with changes to surface roughness, the initial compressive load prior to an experiment and with the separation velocity of the plates. The different slip characteristics appear to arise from the concentration dependent way in which particles interact with the rough surface topography.

Using Climate to Explain and Predict West Nile Virus Risk in Nebraska

We used monthly precipitation and temperature data to give early warning of years with higher West Nile Virus (WNV) risk in Nebraska. We used generalized additive models with a negative binomial distribution and smoothing curves to identify combinations of extremes and timing that had the most influence, experimenting with all combinations of temperature and drought data, lagged by 12, 18, 24, 30, and 36 months. We fit models on data from 2002 through 2011, used Akaike's Information Criterion (AIC) to select the best-fitting model, and used 2012 as out-of-sample data for prediction, and repeated this process for each successive year, ending with fitting models on 2002-2017 data and using 2018 for out-of-sample prediction. We found that warm temperatures and a dry year preceded by a wet year were the strongest predictors of cases of WNV. Our models did significantly better than random chance and better than an annual persistence naïve model at predicting which counties would have cases. Exploring different scenarios, the model predicted that without drought, there would have been 26% fewer cases of WNV in Nebraska through 2018; without warm temperatures, 29% fewer; and with neither drought nor warmth, 45% fewer. This method for assessing the influence of different combinations of extremes at different time intervals is likely applicable to diseases other than West Nile, and to other annual outcome variables such as crop yield.

Financial Conflicts of Interest at FDA Drug Advisory Committee Meetings

The U.S. Food and Drug Administration's drug advisory committees provide expert assessments of the safety and efficacy of new therapies considered for approval. A committee hears from a variety of speakers, from six groups, including voting members of the committee, FDA staff members, employees of the pharmaceutical company seeking approval of a therapy, patient and consumer representatives, expert speakers invited by the company, and public participants. The committees convene at the request of the FDA when the risks and harms of novel products are not immediately clear, and their final decisions carry significant weight, as most therapies that receive advisory committee approval are subsequently approved by the FDA. In recent years, across a series of diverse publications, the financial conflicts of interest of each category of participants in the meetings have been investigated. Here, we summarize these findings and their ethical implications, focusing on the FDA Oncologic Drugs Advisory Committee, and we suggest ways to move toward more transparent and impartial advisory committee meetings.

Most medical practices are not parachutes: a citation analysis of practices felt by biomedical authors to be analogous to parachutes

BACKGROUND

In a 2003 paper in BMJ, the authors made the tongue-in-cheek observation that there are no randomized controlled trials (RCTs) of parachutes. This paper has been widely read, cited and used to argue that RCTs are impractical or unnecessary for some medical practices. We performed a study to identify and evaluate claims that a medical practice is akin to a parachute.

METHODS

Using Google Scholar, we identified all citations to the 2003 paper. We searched for claims that a specific practice was akin to a parachute. For each practice, we identified the desired outcome of the practice, and searched Google Scholar and ClinicalTrials.gov for RCTs that were conducted, ongoing, halted, planned or unpublished.

RESULTS

Of 822 articles citing the original paper, 35 (4.1%) argued that a medical practice was akin to a parachute. Eighteen of the 35 (51%) concerned mortality or live birth, and 17 (49%) concerned a lesser outcome. For 22 practices (63%), we identified 1 or more RCTs: in 6 cases (27%), the trials showed a statistically significant benefit of the practice; in 5 (23%), the trials rejected the practice; in 5 (23%), the trials had mixed results; in 2 (9%), the trials were halted; and in 4 (18%), the trials were ongoing. Effect size was calculated for 5 of the 6 practices for which RCTs gave positive results, and the absolute risk reduction ranged from 11% to 30.8%, corresponding to a number needed to treat of 3-9.

INTERPRETATION

Although there is widespread interest regarding the BMJ paper arguing that randomized trials are not necessary for practices of clear benefit, there are few analogies in medicine. Most parachute analogies in medicine are inappropriate, incorrect or misused.

Attitudes and barriers to providing dietary advice: perceptions of dental hygienists and oral health therapists

OBJECTIVES

Effective dietary counselling in a dental setting can significantly reduce the risk of oral disease. However, studies suggest that dental professionals are not instigating dietary advice on a regular basis, and there is a lack of current information of the barriers experienced that limit the delivery of dietary advice. The aim of this study was to investigate the current attitudes and practice behaviours of dental hygienists and oral health therapists in NSW, Australia, regarding dietary advice, and identify the barriers that limit its delivery.

METHODS

A convenience sample of dental hygienists and oral health therapists were surveyed using a mail-out questionnaire. The questionnaire investigated the demographic data of participants, the attitudes and practice behaviours of participants, the perceived barriers and current dietary resources accessed by participants.

RESULTS

Of 987 dental hygienists and oral health therapists, 426 participants responded. The study results suggest that many dental hygienists and oral health therapists have positive beliefs regarding the importance of dietary counselling. However, there are a multitude of barriers preventing the delivery of dietary advice; these include time, patient compliance, patient knowledge of nutrition topics, personal counselling skills and practitioners' knowledge of nutrition.

CONCLUSION

Whilst dental hygienists and oral health therapists recognize the importance of diet and have positive attitudes towards providing dietary advice to patients, this study identified many barriers preventing implementation in practice. This information may be used to develop targeted strategies aimed at overcoming these barriers and improving behaviours.

Introducing loupes to clinical practice: dental hygienists experiences and opinions

OBJECTIVES

Recent literature has identified a number of potential advantages in wearing loupes for dental hygienists, including improved quality of care and ergonomics. The aim of the study was to determine dental hygienists' opinions about wearing loupes.

METHODS

A short online survey was distributed to all dental hygienists who had recently participated in a study investigating the efficacy of loupes on musculoskeletal disorders; all had only worn loupes for a 6-month period, and prior to the study had not worn loupes. All of those invited completed the survey (n = 12), achieving a 100% response rate.

RESULTS

The majority of respondents noted that the loupes were adaptable to wear; however, only one-quarter of hygienists surveyed were wearing them often following the study. Respondents identified that the biggest advantage to loupes was calculus removal (91.7%), and most indicated that they felt the quality of their work increased when wearing loupes (75%). The biggest disadvantage to wearing loupes was the adjustment period (50%), with limited depth of vision, headache, vertigo and infection control noted by at least one-third of respondents.

CONCLUSIONS

This study revealed that hygienists identify both benefits and limitations to wearing loupes, and therefore, ongoing support may be required for hygienists adopting their use in clinical practice.

Comparison of efficacy, pharmacokinetics, and immunogenicity between infliximab mono- versus combination therapy in ulcerative colitis

BACKGROUND

The association of concomitant immunosuppressant use with infliximab (IFX) and therapeutic outcomes in correlation with pharmacokinetic properties in ulcerative colitis (UC) remains unclear.

AIMS

To assess the effect of concomitant immunosuppressant use on the duration of IFX therapy, and the pharmacokinetic properties of IFX in patients with UC.

METHODS

A retrospective analysis of UC patients treated with IFX. Duration of efficacious IFX therapy, and serum IFX and antibody-to-IFX (ATI) levels were compared between those receiving IFX as monotherapy and in combination with an immunosuppressant.

RESULTS

Among the 85 UC patients who received IFX, 46 (54.1%) received concomitant immunosuppressants, and 38 (45.9%) received IFX monotherapy. Concomitant immunosuppressant use was associated with increased duration of IFX therapy as 90% of patients receiving immunosuppressants remained on therapy at 1 year versus 61% of patients on monotherapy (Log-rank, P = 0.016). Concomitant immunosuppressant use, as compared with monotherapy, was associated with greater IFX levels (20.4 mg/L vs 10.5 mg/L, P = 0.025) and less frequent ATI formation (4.5% vs 33.3%, P = 0.031). Patients receiving greater than 2.0 mg/kg of azathioprine had greater IFX lev l than those receiving less than 2.0 mg/kg (26.0 vs 10.6 mcg/mL, P = 0.03) and those receiving IFX monotherapy (26.0 vs 11.2 mcg/mL, P = 0.03). The duration of IFX therapy among patients receiving less than 2.0 mg/kg azathioprine was indistinguishable from patients on IFX monotherapy (Log-rank, P = 0.95).

CONCLUSION

Concomitant immunosuppressant therapy with IFX improves outcomes in UC as shown by increased duration of therapy, decreased immunogenicity against IFX, and increased blood levels of IFX. Our data suggest that this benefit may be dependent on the dose of concomitant immunosuppression.

The provision of dietary advice by dental practitioners: a review of the literature

PURPOSE

The aim of this literature review was to examine the dietary advice practices of dentists and dental hygienists and to identify factors influencing whether practitioners provide dietary advice to patients.

METHODS

A systematic search was carried out of the electronic databases CINHAL Plus, Medline via OVID and the Cochrane Library, using the search terms 'Diet', 'Nutrition', 'Dental hygienists' and 'Dentists'. Articles included in the review were all empirical studies and existing literature reviews examining the provision of dietary advice practices of dentists, dental hygienists and dental students. Only articles published after 1993 were included in the review to better reflect the current practices of dental practitioners.

RESULTS

The literature revealed that dietary advice is rarely provided by dental practitioners, and that when dietary advice is provided it is often limited. The literature also established that provision of dietary advice is influenced by a number of factors, including financial considerations, time constraints and the dietary education of dental practitioners.

CONCLUSIONS

Further research is required to strengthen the findings from the review and to investigate dietary advice specific to the prevention of dental erosion. Additional research is also required to examine dental curricula and assess the dietary advice practices of dental students.

The effect of wearing loupes on upper extremity musculoskeletal disorders among dental hygienists

OBJECTIVES

It is well established that musculoskeletal disorders (MSD) are a significant occupational health issue for dentists and hygienists. Despite this, there has been little advancement in the application of ergonomic principles in the dental profession. While the use of loupes is often promoted as an ergonomic solution, there is little published research to robustly support this claim. The aim of the present study was to investigate the effect of the use of loupes on upper extremity MSD among dental hygienists.

METHODS

The study was conducted using an exploratory pretest and post-test design, comparing musculoskeletal measures in practising dental hygienists wearing loupes with final-year dental hygiene students who did not wear loupes. Pre- and post-test measures included valid self-reported and objective outcome measures and were measured at baseline and 6 months following the intervention. Statistical analysis was conducted as a series of mixed anovas with time and treatment as the independent variables.

RESULTS

The analysis revealed a significant interaction between time and treatment for the Disabilities of the Shoulder, Arm and Hand (DASH) scores (P < 0.04), indicating an improvement in symptoms for the treatment group but a reversed trend for the controls. There was also a significant mean increase in scapular position measures; however, this finding was evident in both groups, indicating that these were not a result of the intervention.

CONCLUSIONS

Overall, this study suggests that wearing loupes appears to have both positive and negative effects on upper extremity MSD among dental hygienists. Ongoing research is required to determine the long-term effects of loupes wear, over an extended period of time.

Absolute Bioavailability of Imatinib (Glivec®) Orally versus Intravenous Infusion

The purpose of this study was to investigate the absolute bioavailability of a single oral dose of imatinib (Glivec), 400 mg (capsules vs. oral solution), compared with imatinib, 100 mg (intravenous [i.v.] infusion), in healthy subjects. Twelve subjects received a single treatment in each treatment period: a 400-mg oral dose of imatinib in capsule form or as a solution or a 100-mg i.v. infusion of imatinib. Plasma imatinib concentrations were measured following each treatment; pharmacokinetic parameters and absolute bioavailability were determined. Absolute bioavailability values (compared with i.v. infusion) for the imatinib capsule and oral solution were 98.3% and 97.2%, respectively. Both the rate and extent of imatinib absorption, as measured by C(max), partial AUC, and total AUC, were similar for the oral solution and the imatinib capsule intended for the market. The 400-mg oral dose of imatinib, as a capsule or a solution, was completely absorbed and was almost completely bioavailable (> 97%).

Capillary electrophoretic development of aptamers for a glycosylated VEGF peptide fragment

The emergence of functional genomics and proteomics has added to the growing need for improved analysis methods that can detect and distinguish between protein variants resulting from allelic variation, mutation, or post-translational modification. Aptamers, single-stranded DNA or RNA molecules that fold into three-dimensional structures conducive to binding targets, have become an attractive alternative to antibodies for this type of analysis. Although aptamers have been developed for a wide range of target species, very few sequences have been identified that bind selectively to proteins with specific post-translational modifications. Using capillary electrophoresis-based selection, we have developed DNA aptamer sequences that selectively bind an N-glycosylated peptide fragment of vascular endothelial growth factor (VEGF). The selection method incorporates alternating positive- and counter-selection steps in free solution in order to obtain aptamers with both high affinity toward the glycosylated target and high selectivity versus a non-glycosylated variant. Affinity capillary electrophoresis and surface plasmon resonance binding assays indicate these sequences have low-µM dissociation constants and preferentially bind the glycosylated peptide with as much as 50-fold specificity. Such aptamers could serve as tools for rapid and simple monitoring of disease-linked functional changes in proteins, with potential applications in drug screening and disease diagnosis.

Prevalence and correlates of musculoskeletal disorders among Australian dental hygiene students

INTRODUCTION

Although musculoskeletal disorders (MSD) have been identified as a significant occupational health issue for dental hygienists, few studies have explored this problem among the dental hygiene student population.

AIM

The aim of this study was to investigate the prevalence and correlates of MSD among a selection of undergraduate dental hygiene students in Australia.

METHODOLOGY

A self-reporting questionnaire was distributed to dental hygiene students at an Australian university during 2008, from which a response rate of approximately 72% was achieved.

RESULTS

Musculoskeletal disorders were most commonly reported by students at the neck (64.29%), lower back (57.94%) and shoulder (48.41%) regions. Logistic regression indicated various correlations with MSD. Students who did not undertake regular exercise every week experienced an increased risk of lower back pain [Odds Ratio (OR): 4.88, 95% Confidence Interval (CI): 1.75-14.9]. Students undertaking 16-20 h of desk-based study per week were much more likely to report neck pain (OR: 19.7, 95% CI: 1.34-378.94). Working 6-10 h on a computer each week was a risk factor for shoulder (OR: 7.03, 95% CI: 1.42-39.49) and upper back pain (OR: 5.29, 95% CI: 1.21-25.56).

CONCLUSIONS

Overall, this study suggests that MSD are a reasonably common problem for dental hygiene students in Australia. As such, further studies are required to establish epidemiological patterns of MSD, and our profession will need to carefully consider preventive strategies to help minimize the impact of this important occupational health issue on the next generation of dental hygienists.

Genetic changes of Wnt pathway genes are common events in metaplastic carcinomas of the breast

PURPOSE

Metaplastic carcinomas are distinct invasive breast carcinomas with aberrant nonglandular differentiation, which may be spindle, squamous, or chondroid. The limited effective treatments result from the lack of knowledge of its molecular etiology. Given the role of the Wnt pathway in cell fate and in the development of breast cancer, we hypothesized that defects in this pathway may contribute to the development of metaplastic carcinomas.

DESIGN

In 36 primary metaplastic carcinomas, we comprehensively determined the prevalence of and mechanism underlying beta-catenin and Wnt pathway deregulation using immunohistochemistry for beta-catenin expression and localization and mutational analysis for CTNNB1 (encoding beta-catenin), APC, WISP3, AXIN1, and AXIN2 genes. By immunohistochemistry, normal beta-catenin was seen as membrane staining, and it was aberrant when >5% of tumor cells had nuclear or cytoplasmic accumulation or reduced membrane staining.

RESULTS

By immunohistochemistry, aberrant beta-catenin was present in 33 of 36 (92%) cases, revealing deregulation of the Wnt pathway. CTNNB1 missense mutations were detected in 7 of 27 (25.9%) tumors available for mutation analyses. All mutations affected the NH(2)-terminal domain of beta-catenin, presumably rendering the mutant protein resistant to degradation. Two of 27 (7.4%) tumors had mutations of APC, and 5 (18.5%) carried a frame shift mutation of WISP3. No AXIN1 or AXIN2 mutations were found.

CONCLUSIONS

Activation of the Wnt signaling pathway is common in this specific subtype of breast carcinoma. The discovery of CTNNB1, APC, and WISP3 mutations may result in new treatments for patients with metaplastic carcinomas of the breast.

Phase I and Pharmacokinetic Study of Imatinib Mesylate in Patients With Advanced Malignancies and Varying Degrees of Liver Dysfunction: A Study by the National Cancer Institute Organ Dysfunction Working Group

Purpose

To develop dosing guidelines and to evaluate the pharmacokinetics of imatinib in patients with liver dysfunction (LD).

Patients and Methods

Patients (N = 89) with varying solid tumors and liver function were stratified into four groups according to serum total bilirubin and AST and were treated with escalating doses of imatinib. Plasma and urine were assayed for concentrations of imatinib and its active metabolite, CGP74588 .

Results

In the mild LD group, dose-limiting toxicity, specifically nausea/vomiting and fatigue, occurred in two patients at the 600 mg/d dose level. In the moderate and severe LD groups, the maximal dose evaluated was 300 mg/d. Grade 3 to 4 toxicities consisted primarily of liver function test elevations (24%), nausea/vomiting (10%), fatigue (6%), and edema (5%). After the first imatinib dose, the mean (± SD) dose-normalized areas under the plasma concentration-time curve from time 0 to infinity (AUC0-∞) were 162 ± 155, 171 ± 72, 182 ± 157, and 185 ± 172 (μg/mL × h)/mg for normal, mild, moderate, and severe LD groups, respectively. Renal excretion of imatinib was less than 10% of the total dose in all groups.

Conclusion

Imatinib exposure (as measured by the dose-normalized AUC) did not differ between patients with normal liver function and those with LD. The maximal recommended dose of imatinib for patients with mild LD is 500 mg/d. Dosing guidelines for patients with moderate and severe LD remain undetermined.

Apneic preterms and methylxanthines: arousal deficits, sleep fragmentation and suppressed spontaneous movements

OBJECTIVE

To determine if apneic preterm infants currently treated with methylxanthines develop evidence of sleep deprivation from cumulative arousal and motor activational effects.

STUDY DESIGN

Sleep, wake, arousal and actigraphic movements were monitored in extubated clinically stable premature infants (N=37). Neonates were free of other medications for >72 h and were grouped based on methylxanthine exposure: >5 days with caffeine (n=14), >5 days theophylline (n=13) or no prior exposure (n=10).

RESULT

Duration of methylxanthine treatment predicted increased arousals, wakefulness and actigraphic movements, and decreased active sleep. Recording from 1200 to 0500 hours, methylxanthine-treated groups showed reductions in all arousal parameters: waking state, number of wake epochs, brief arousals and composite arousal index, and shorter fast-burst, sleep-related motility than untreated controls.

CONCLUSION

In apneic preterms, chronic methylxanthine treatment appears to produce sleep deprivation secondary to the stimulatory action of methylxanthines on arousal and motor systems.

Annexinopathies

Annexins comprise a conserved family of proteins characterised by their ability to bind and order charged phospholipids in membranes, often in response to elevated intracellular calcium. The family members (there are at least 12 in humans) have become specialised over evolutionary time and are involved in a diverse range of cellular functions both inside the cell and extracellularly Although a mutation in an annexin has never been categorically proven to be the cause of a disease state, they have been implicated in pathologies as diverse as autoimmunity, infection, heart disease, diabetes and cancer. 'Annexinopathies' were first described by Jacob H. Rand to describe the pathological sequelae in two disease states, the overexpression of annexin 2 in a patients with a haemorrhagic form of acute promyelocytic leukaemia, and the under-expression of annexin 5 on placental trophoblasts in the antiphospholipid syndrome. In this chapter we will outline some of the more recent observations in regard to these conditions, and describe the involvement of annexins in some other major causes of human morbidity.

First-receiver hospital decontamination: an 8-step approach to a progressive and practical program

The effectiveness of hospital decontamination programs begins with planning, preparation, and practice. A well-thought-out hospital decontamination program encompasses complexities that are not always apparent. In disaster situations, the victim, hospital, patients, and staff are placed at serious risk if untrained, unprepared employees perform emergency decontamination procedures at the hospital-receiving site. The authors describe 8 steps to developing an emergency preparedness program and team with decontamination capabilities to facilitate emergency response in the first-receiver hospital.

Low IgE monoclonal gammopathy level in serum highlights 20-yr survival in a case of IgE multiple myeloma

This report describes the diagnosis, follow-up, and problems measuring serum immunoglobulin E (IgE) levels in a case of IgE myeloma with 20-yr survival. Serum and urine protein electrophoresis, immunofixation, and the N Latex IgE test were used to characterize the monoclonal proteins. The diagnosis of multiple myeloma in a 56-yr-old man was based on 5.4 g/24 h of monoclonal free lambda chain in urine and bone marrow findings of 23.5% plasma cells (19% mature and 4.5% atypical). IgE lambda monoclonal protein in serum measured 506,000 microg/L (210 833 IU/mL). The lack of other clinical findings of multiple myeloma places this case in the category of 'smoldering or indolent myeloma'. Measurement of serum IgE levels was complicated by the need to predilute serum to avoid antigen excess. Following chemotherapy, the patient went into clinical remission, eventually dying of complications of emphysema. This case expands the recognized clinical spectrum of IgE multiple myeloma.

Biliary Excretion of Imatinib Mesylate and Its Metabolite CGP 74588 in Humans

Imatinib mesylate, licensed to treat chronic myelogenous leukemia and gastrointestinal stromal tumors, is metabolized by cytochrome P450 3A and undergoes little renal excretion, but its biliary excretion by humans is uncharacterized. Liquid chromatography-mass spectrometry was used to quantitate imatinib and its metabolite CGP 74588 in the bile of two patients with biliary stents; the ratio of imatinib:CGP 74588 in each was approximately 9:1. In the first patient, who was receiving long-term therapy with imatinib 400 mg/day and had normal liver function tests, biliary imatinib accounted for 17.7% of the daily dose and CGP 74588 accounted for 2.1%. In the second patient, who had elevated liver function tests and was studied after his first dose of imatinib 300 mg, biliary imatinib accounted for only 1.8% of the daily dose and CGP 74588 accounted for 0.2%. These data show both the qualitative similarities and the quantitative variability in biliary excretion of imatinib and its principal metabolite.

An IgM class anti-neutrophil cytoplasm antibody inhibits neutrophil adhesion and apoptosis via a Syk dependent signaling cascade

Anti-neutrophil cytoplasm antibodies (ANCA) with specificity for myeloperoxidase (MPO) are implicated as pathogenic agents in pauci-immune systemic vasculitis. In agreement with previously published observations we show that human neutrophils incubated with an MPO-specific IgG class monoclonal antibody are pro-adhesive and undergo apoptosis more readily in vitro. If apoptotic neutrophils are incubated with this antibody they are readily phagocytosed by macrophages and we show that 'blocking' antibodies to FcgammaRIIa (CD32) on the macrophage inhibit this process. We also examined the effect of E3MPO, a monoclonal anti-MPO antibody derived from a patient with severe systemic vasculitis. E3MPO is closely related to the cold-agglutinins and bears an epitope recognized by the monoclonal antibody 9G4 which is expressed on antibodies derived from the V4-34 germ-line immunoglobulin gene. In previous studies, we have shown that anti-MPO antibodies present in sera from patients with vasculitis often bear this epitope. In contrast to the IgG-class antibody, incubation of neutrophils with E3MPO inhibited neutrophil adhesion and apoptosis. Apoptotic neutrophils however were phagocytosed more readily by macrophages in the presence of E3MPO. The effects of E3MPO on neutrophil adhesion and apoptosis were inhibited by piceatannol, an inhibitor of Syk-family kinases; activation of which is associated with cross-linking of the beta(2)-integrins. We show that surface-expressed MPO co-localizes with these beta(2)-integrins and suggest that cross-linking of beta(2)-integrin-bound MPO by polyvalent antibodies could result in signaling through these receptors. We have demonstrated that there are different consequences of Fcgamma-receptor-dependent and -independent signaling mediated by ANCA.

Regioselective Oxidations of Benzocarbaporphyrins with Ferric Chloride: A Facile Synthesis of Bridged [18]Annulene Ketals with Strong Absorptions in the Far Red and an Unexpected Halogenation Reaction at the Interior Carbon Atom

Benzocarbaporphyrins 4 were found to undergo regioselective oxidations with ferric chloride in methanol, ethanol, isopropyl alcohol, or ethylene glycol to give bridged benzo[18]annulene ketal derivatives 5 in excellent yields. These polar derivatives were generally isolated in a monoprotonated form and the corresponding free bases appeared to be relatively unstable. Addition of TFA resulted in the formation of spectroscopically distinct dications. The ketals 5 were highly diatropic in nature, showing the internal alkoxy substituents upfield beyond -1 ppm in their proton NMR spectra. The external meso-protons resonated near 10 ppm, confirming the presence of a strong aromatic ring current. The UV-vis spectra for 5 showed a Soret band at 422 nm, and two strong absorptions in the far red at 751 and 832 nm. A carbaporphyrin with a fused acenaphthylene ring was also oxidized with ferric chloride and this produced a ketal derivative with still further bathochromically shifted absorptions particularly for the Soret band. Also, the use of different alcohols in these reactions allows the overall polarity of these ketal products to be controlled and this could have merit in biomedical applications. Reaction of carbaporphyrin 4a with aqueous ferric chloride afforded the corresponding 21-chloro derivative 20 in good yields, and at longer reaction times a nonaromatic dione was isolated. Aqueous ferric bromide gave a 21-bromocarbaporphyrin product but in this case very poor yields (<10%) were noted. Mechanisms are proposed to explain the formation of these unusual oxidation products. The structure of 21-chlorocarbaporphyrin 20 was further demonstrated by X-ray crystallography. The presence of the interior chlorine atom was found to tilt the indene moiety by 29.59(4) degrees relative to the [18]annulene macrocyclic ring. The crystal packing for 20 shows offset face-to-face pi-stacking interactions that link the porphyrinoid molecules as closely paired dimers.

Design, parallel synthesis, and crystal structures of pyrazinone antithrombotics as selective inhibitors of the tissue factor VIIa complex

Structure-based drug design (SBDD) and polymer-assisted solution-phase (PASP) library synthesis were used to develop a series of pyrazinone inhibitors of the Tissue Factor/Factor VIIa (TF/VIIa) complex. The crystal structure of a tripeptide-alpha-ketothiazole complexed with TF/VIIa was utilized in a docking experiment to identify the pyrazinone core as a starting scaffold. The pyrazinone core could orient the substituents in the correct spatial arrangement to probe the S1, S2, and S3 pockets of the enzyme. A multistep PASP library synthesis was designed to prepare the substituted pyrazinones varying the P1, P2, and P3 moieties. Hundreds of pyrazinone TF/VIIa inhibitors were prepared and tested in several serine protease enzyme assays involved in the coagulation cascade. The inhibitors exhibited modest activity on TF/VIIa with excellent selectivity over thrombin (IIa) and Factor Xa. The structure-activity relationship of the pyrazinone inhibitors will be discussed and X-ray crystal structures of selected compounds complexed with the TF/VIIa enzyme will be described. This study ultimately led to the synthesis of compound 34, which exhibited 16 nM (IC50) activity on TF/VIIa with >6250 x selectivity vs Factor Xa and thrombin. This potent and highly selective inhibitor of TF/VIIa was chosen for preclinical, intravenous proof-of-concept studies to demonstrate the separation between antithrombotic efficacy and bleeding side effects in a nonhuman primate model of electrolytic-induced arterial thrombosis.

Structure-based drug design of pyrazinone antithrombotics as selective inhibitors of the tissue factor VIIa complex

Structure-based drug design coupled with polymer-assisted solution-phase library synthesis was utilized to develop a series of pyrazinone inhibitors of the tissue factor/Factor VIIa complex. The crystal structure of a tri-peptide ketothiazole complexed with TF/VIIa was utilized in a docking experiment that identified a benzyl-substituted pyrazinone as a P(2) surrogate for the tri-peptide. A 5-step PASP library synthesis of these aryl-substituted pyrazinones was developed. The sequence allows for attachment of a variety of P(1) and P(3) moieties, which led to synthesis pyrazinone 23. Compound 23 exhibited 16 nM IC(50) against TF/VIIa with >6250x selectivity versus Factor Xa and thrombin. This potent and highly selective inhibitor of TF/VIIa was chosen for pre-clinical intravenous proof-of-concept studies to demonstrate the separation between antithrombotic efficacy and bleeding side effects in a primate model of thrombosis.

Liquid chromatographic-mass spectrometric assay for quantitation of imatinib and its main metabolite (CGP 74588) in plasma

Imatinib mesylate (Gleevec, Glivec, STI571) is a targeted, small molecule inhibitor of the oncogenes, BCR/ABL and c-KIT, and has striking antitumor activity in patients with chronic myelogenous leukemia or gastrointestinal stromal tumors. We have developed a liquid chromatographic-electrospray ionization mass spectrometric (LC-MS) method for quantifying imatinib and its main metabolite (CGP 74588) in plasma. The assay uses deuterated imatinib as the internal standard; acetonitrile deproteination; a Phenomenex Luna C(18)(2) (5 microm, 50 x 4.6 mm) reversed-phase analytical column; a gradient mobile phase of 0.1% formic acid in methanol and water; and mass spectrometric detection using electrospray positive mode electron ionization. The assay has a lower limit of quantitation (LLOQ) of 30 ng/ml and is linear between 30 and 10000 ng/ml for both imatinib and CGP 74588. We demonstrated the suitability of this assay for imatinib using it to quantify the concentrations of imatinib and CGP 74588 in plasma of a patient given a 200-mg dose of imatinib orally. We believe that this LC-MS assay should be an important tool for future pharmacokinetic studies of imatinib.

Conjugated macrocycles related to the porphyrins. 21. Synthesis, spectroscopy, electrochemistry, and structural characterization of carbaporphyrins

The "3 + 1" variant of the MacDonald condensation has been shown to be an excellent methodology for synthesizing carbaporphyrins. In particular, 1,3-indenedicarbaldehyde condenses with tripyrranes in the presence of TFA to give, following oxidation with DDQ, a series of benzocarbaporphyrins in excellent yields. Triformylcyclopentadienes also afford carbaporphyrin products, albeit in low yields ranging from 5 to 8%. These hybrid bridged annulene structures have porphyrin-like electronic absorption spectra with strong Soret bands near 420 nm and a series of Q-bands through the visible region. The proton NMR spectrum confirms the presence of a strong diamagnetic ring current, and the meso-protons show up at 10 ppm, while the internal CH is shielded to approximately -7 ppm. Carbaporphyrins undergo reversible protonation with TFA. Initial addition of acid affords a monocation, although mixtures of protonated species are observed in the presence of moderate concentrations of TFA. However, in the presence of 50% TFA a C-protonated dication is generated. The dications relocate the pi-delocalization pathway through the benzo moiety of benzocarbaporphyrins, and these therefore represent bridged benzo[18]annulenes, although they nevertheless retain powerful macrocyclic ring currents. Carbaporphyrins with fused acenaphthylene and phenanthrene rings have been prepared, and the former demonstrated significantly larger bathochromic shifts in UV-vis spectroscopy that parallel previous observations for acenaphthoporphyrins. A diphenyl-substituted benzocarbaporphyrin 19b was also characterized by X-ray crystallography, and these data show that the macrocycle is reasonably planar although the indene subunit is tilted out of the mean macrocyclic plane by 15.5 degrees. The structural data indicates that the preferred tautomer in the solid state has the two NH's flanking the pyrrolene unit in agreement with previous spectroscopic and theoretical studies. Cyclic voltammetry for carbaporphyrin 19a was more complex than for true porphyrins, showing five anodic waves and two quasi-reversible reductive couples.

Bedsharing, temperament, and sleep disturbance in early childhood

STUDY OBJECTIVE

Temperament was explored as a factor in both night-waking and bedsharing in preschool-aged children.

DESIGN

Bedsharers and solitary sleepers were categorized based on the frequency of current bedsharing. MANOVA was used to examine associations among temperament and sleep measures.

SETTING

Two preschools affiliated with a rural university in the Northeast United States. Participants. 67 children between 2.4-5.6 years of age from two University-affiliated preschools were studied.

INTERVENTION

Child temperament was rated by parents and teachers using the Carey Temperament Scale and compared to night-waking, current sleep habits, and the circumstances in which bedsharing occurred

MEASUREMENTS AND RESULTS

Parents and preschool teachers completed the Carey Temperament Scale for 3-7 year olds. Parents also scored the Sleep Habits Inventory and the Sleeping Arrangements Inventory, which provided a current and retrospective history of the child's sleep location and sleep patterns. Parents' ratings showed that bedsharers have less regular bedtimes; difficulty with sleep onset; more night-waking; and seek out the parents following awakening during the night. Temperamentally, bedsharers were found to be more intense and exhibit less adaptability and rhythmicity. However, teachers' temperament ratings did not predict bedsharing and were not concordant with parental ratings.

CONCLUSIONS

These findings suggest that bedsharing at preschool age is a complex phenomenon related to parents' ratings of child temperament, sleep habits, and disturbances such as night waking. Implications for the clinical assessment of sleep disorders are discussed.

A new method for pulse oximetry possessing inherent insensitivity to artifact

A new method for pulse oximetry is presented that possesses an inherent insensitivity to corruption by motion artifact, a primary limitation in the practical accuracy and clinical applicability of current technology. Artifact corruption of the underlying photoplethysmographic signals is reduced in real time, using an electronic processing methodology that is based upon inversion of a physical artifact model. This fundamental approach has the potential to provide uninterrupted output and superior accuracy under conditions of sustained subject motion, therefore, widening the clinical scope of this useful measurement. A new calibration technique for oxygen saturation is developed for use with these processed signals, which is shown to be a generalization of the classical interpretation. The detailed theoretical and practical issues of implementation are then explored, highlighting important engineering simplifications implicit in this new approach. A quantitative investigation of the degree of insensitivity to artifact is also undertaken, with the aid of a custom electronic system and commercial pulse oximeter probes, which is compared and contrasted with the performance of a conventional implementation. It is demonstrated that this new methodology results in a reduced sensitivity to common classes of motion artifact, while retaining the generality to be combined with conventional signal processing techniques.

Transactional conflict between psychobiology and culture in the etiology of postpartum depression

In vulnerable individuals, postpartum depression may be triggered by the disruption of neuropsychological processes during pregnancy and parturition. It is proposed that in Western societies pre- and postnatal psychological and instrumental needs are poorly met and this crisis may interact with neurophysiological factors in compromising maternal psychological functioning. The influence of developmental factors and psychological and physical stressors are discussed in relation to women's neuropsychological health during the peripartal transition. It is hypothesized that the environmental milieu may support, neglect or derail the mother's psychobiological transition from pregnancy to effective postnatal parenting and resumption of family and work roles.

Multi-step polymer-assisted solution-phase (PASP) library synthesis of functionalized diaminobenzamides

A parallel solution-phase library synthesis of functionalized diaminobenzamides is described. The four-step library synthesis is accomplished using polymer-assisted solution-phase (PASP) synthesis techniques. This high-yielding, multi-step sequence utilizes sequestering resins for the removal of reactants, reactant by-products, and employs a resin capture/release strategy as a key library synthesis step. Step one of the sequence relies on the displacement of an activated fluoro-group from the aromatic ring of 1a, b with a variety of primary amines to introduce the first diversity position. Step two is hydrolysis of the benzoate ester to a benzoic acid which is subsequently captured on a polyamine resin, washed, and released to give 4a, b in pure form. Step three utilizes PASP resins to mediate the amide coupling of a benzoic acid with a variety of primary amines to give the aminonitrobenzamides 5a, b and introduces the second diversity position. Step four is the parallel reduction of the aminonitrobenzamides 5a, b to the functionalized diaminobenzamides 6a, b. This library synthesis proceeds with high overall purities which average 80 % over the 4-step sequence.

Transactional conflict between psychobiology and culture in the etiology of postpartum depression

In vulnerable individuals, postpartum depression may be triggered by the disruption of neuropsychological processes during pregnancy and parturition. It is proposed that in Western societies pre- and postnatal psychological and instrumental needs are poorly met and this crisis may interact with neurophysiological factors in compromising maternal psychological functioning. The influence of developmental factors and psychological and physical stressors are discussed in relation to women's neuropsychological health during the peripartal transition. It is hypothesized that the environmental milieu may support, neglect or derail the mother's psychobiological transition from pregnancy to effective postnatal parenting and resumption of family and work roles.

Chemical stress relaxation of polyglycolic acid suture

Chemical stress relaxation methods are employed to study chemical and mechanical factors influencing the degradation of uncoated polyglycolic (PG) sutures. Specially constructed instrumentation is used to study the kinetics of the load bearing capability of PG (Dexon¿) 3-0 sutures in hydrolytic solution. The effects of pH, temperature, strain rate, and initial load on the rate of chemical stress relaxation are presented. Data show how mechanical factors such as the rate of loading (related to the speed of knot tying), as well as the final tension, are related to the rate of structural degradation. Maximum stability is observed at approximately 40 degrees C, with slower degradation both above and below this point. Results show that the slower and tighter the suture is pulled, the greater its ability to sustain tensile loads during hydrolysis.

Artifact reduction in photoplethysmography

Motion artifact reduction in photoplethysmography, and therefore by implication in pulse oximetry, is achieved with a novel nonlinear methodology. The physical origins of the photoplethysmographic signals are explored in relation to a nonlinear measure of the observed intensity fluctuations. It is demonstrated that the nonlinearity renormalizes the received pulsations with optical information in a manner that aids physical interpretation. A heuristic physical model for the motion artifact is introduced and experimentally justified, with an inversion for artifact reduction being simplified by the nonlinearity. A practical implementation technique is discussed with emphasis placed on the resultant rescaling of the static and the dynamic portions of the signals. It is noted that this implementation also has the desirable effect of reducing any residual ambient artifact. The scope and power of this methodology is investigated with the presentation of results from a practical electronic system.

Spontaneous movements during sleep in children: temporal organization and changes with age

Developmental changes in the temporal organization of spontaneous movements during sleep was studied in children between 9 months and 11 years of age. Subjects were monitored in the home environment for the entire sleep period using actigraphy and videography. Rhythmicity in sleep-related spontaneous movements was examined using FFT and chi-square periodogram time series analyses. A dominant periodicity of 60-120 minutes was identified which was found to progressively lengthen with age. A microanalysis of the temporal structure of movements revealed a developmental decline in bout duration, but a paradoxical increase in bout frequency. These results show that motor activity becomes less robust and more fragmented as development progresses while retaining underlying rhythmic integrity, and argue for the dynamic influence of CNS maturation on the organization and expression of sleep-related spontaneous movements.

Effect of long-term beta2-agonist dosing on human cardiac beta-adrenoceptor expression in vivo: comparison with changes in lung and mononuclear leukocyte beta-receptors

BACKGROUND

Tachyphylaxis to the cardiac effects of beta-adrenoceptor stimulation after long-term beta2-agonist administration is well recognized, but the influence on global cardiac beta-adrenoceptor density has not been previously investigated in vivo. Positron emission tomography (PET) has made possible the noninvasive quantification of regional receptor density. This study assesses the effect of long-term beta2-agonist dosing on cardiac beta-adrenoceptors.

METHODS AND RESULTS

Beta-adrenoceptors in the hearts of 29 healthy male subjects aged 35 +/- 8 years were imaged and quantified in vivo by means of PET and compared with the receptor density in the same subjects' lung tissue. Mononuclear leukocyte (MNL) beta-receptor density was determined in vitro by means of a radioligand binding assay. Beta-receptor density was 8.41 +/- 2.03 pmol/gm tissue in heart, 10.81 +/- 1.91 pmol/gm tissue in lung, and 38.0 +/- 17.5 fmol/mg protein on MNLs. There was a weak relationship between cardiac and pulmonary beta-receptor densities (r = 0.45, p < 0.02) but not between cardiac and MNL receptor density. In seven subjects, the measurements were repeated after 2 weeks of albuterol treatment (4 mg orally twice daily and 200 microg inhaled four times daily in the first week, with doubling of the dose during the second week). After the albuterol treatment, beta-receptor density fell on average by 19% (p < 0.05) in the heart compared with 22% (p < 0.05) in the lung and 42% (p < 0.05) in MNLs. Correlations were found between the percentage changes in receptor density in heart and lung (r = 0.98, p < 0.001) and in heart and MNLs (r = 0.99, p < 0.002).

CONCLUSIONS

Two weeks of high-dose albuterol results in equivalent downregulation of beta-receptors in vivo, both in the lung and in the heart.

Pulmonary and cardiac beta-adrenoceptor density in vivo in asthmatic subjects

To examine whether there is a primary deficit in beta-adrenoceptor density in asthma, pulmonary and cardiac beta-receptor density was determined in vivo with positron emission tomography (PET) in 10 male asthmatic subjects (36 +/- 8 yr of age) and compared with that in 30 age-matched normal male subjects (36 +/- 8 yr of age). Pulmonary beta-receptor density was 10.3 +/- 1.8 pmol/g tissue for the asthmatic group and 10.9 +/- 1.9 for the normal group. Cardiac beta-receptor density was 9.1 +/- 3.3 pmol/g for the asthmatic group and 8.8 +/- 2.3 pmol/g for the normal group. There was no difference in either pulmonary or cardiac beta-receptor density between the two groups. In addition, an inverse relationship was observed between FEV1 % predicted and pulmonary beta-receptor density in asthmatic subjects. In conclusion, beta-receptor numbers are normal in untreated asthmatic subjects.

Motoric responses to sucrose in postmature and term infants

Postmature infants calm less when presented with sucrose solutions than term infants. To further assess the influence of postmaturity on sucrose responsivity, several motoric responses were examined in healthy term neonates and chronically stressed postmature (> or = 288 days gestational age (GA) e.g., > 41 weeks) neonates with Clifford's Syndrome tested between 5-91 h of age. Following baseline observations, each subject was presented with 0.1 ml of a 14% sucrose solution for 10 s each min for 5 min, and observations were continued for 5 min following stimulation. During sucrose stimulation and poststimulation phases, postmature infants showed more tremors during quiet state than term infants. Across conditions, postmature infants exhibited increased finger sucking, rhythmic sucking, but less mouth opening and arm movements than healthy, term infants. Sequence analysis revealed that short-latency mouthing, repetitive movements of the upper and lower lips, followed sucrose infusion reliably in postmature infants, but not term infants. These results suggest that postmaturity is associated with: 1. Increased oral behaviors associated with arousal and self soothing; and 2. Increased sucrose reactivity, as indicated by contingent mouthing and increased tremors.