Investigating monotherapy and combination therapy trends in newly diagnosed patients with pulmonary arterial hypertension among EU3 & UK physicians over the COVID-19 pandemic

Background

Pulmonary Arterial Hypertension (PAH) is a form of pulmonary hypertension, where the narrowing of arteries in the lungs restricts blood flow and so increases pressure in the vessels. Studies have demonstrated that initial combination therapies are optimal for PAH management. However, prescription of monotherapy treatment is still prevalent as a first line therapy.

Purpose

The purpose of this research was to investigate prescribing trends of physicians for first line patients with PAH in the UK, Germany, Italy and Spain. We investigated the proportions of newly diagnosed patients and the prescription trends for monotherapy and combination therapy prior to and during the COVID-19 pandemic.

Methods

A multi-country, multi-centre online medical chart review study of patients with PAH was conducted between April – June of 2019, 2020 and 2021 respectively. Recruited from a large access panel, 178 treating cardiologists, pulmonologists & rheumatologists in the UK (n=16), Germany (n=55), Italy (n=55) and Spain (n=52) were screened for duration of practice in their speciality and caseload (≥5 PAH patients in the last 3 months), and provided data on 694 PAH patients (UK = 71, Germany = 206, Italy = 208, Spain = 209). Reported patient data pertained to medical chart information reflecting the prior year, i.e., Q2 2021 data reflected the 2020 period (advent of the COVID-19 pandemic).

Results

In this dataset, there has been a consistent decrease in the proportion of newly diagnosed (i.e. diagnosed within 12 months of being reported) patients reported from 2019 to 2020 and 2021. In 2019, 49% of the reported patients were diagnosed within the last 12 months. However, the newly diagnosed patient population dropped to 37% in 2020 and continued to drop to 27% in 2021. Despite this, there has been an increase in reported first line patients within the newly diagnosed segment from 74% in 2019, to 75% in 2020, then at 87% in 2021. This increase can be seen to coincide with the ongoing COVID-19 pandemic.

In 2019, 58% of reported newly diagnosed patients were recorded as receiving monotherapy. This did drop to 33% in 2020; however, in 2021 monotherapy uptake increased to 47%. Of note, the usage of the endothelin receptor antagonist (ERA) drug class increased from 67% in 2019 to 83% in 2020 but dropped to 69% in 2021.

Conclusions

This data set suggests a decreasing trend in newly diagnosed patients and a gradual shift in treatment type to first line monotherapy prescription, which coincided with the height of the COVID-19 pandemic. More newly diagnosed patients (those diagnosed within 12 months of being reported) are receiving monotherapy treatment at the expense of combination therapy, and this has also coincided with the pandemic. Further investigation using comparator cohort is warranted to assess whether the challenges physicians faced during the pandemic has had a causal effect on the prescribing habits for PAH therapies.

Funding Acknowledgement

Type of funding sources: None.

Using remote sensing to assess peatland resilience by estimating soil surface moisture and drought recovery

Peatland areas provide a range of ecosystem services, including biodiversity, carbon storage, clean water, and flood mitigation, but many areas of peatland in the UK have been degraded through human land use including drainage. Here, we explore whether remote sensing can be used to monitor peatland resilience to drought. We take resilience to mean the rate at which a system recovers from perturbation; here measured literally as a recovery timescale of a soil surface moisture proxy from drought lowering. Our objectives were (1) to assess the reliability of Sentinel-1 Synthetic Aperture Radar (SAR) backscatter as a proxy for water table depth (WTD); (2) to develop a method using SAR to estimate below-ground (hydrological) resilience of peatlands; and (3) to apply the developed method to different sites and consider the links between resilience and land management. Our inferences of WTD from Sentinel-1 SAR data gave results with an average Pearson's correlation of 0.77 when compared to measured WTD values. The 2018 summer drought was used to assess resilience across three different UK peatland areas (Dartmoor, the Peak District, and the Flow Country) by considering the timescale of the soil moisture proxy recovery. Results show clear areas of lower resilience within all three study sites, which often correspond to areas of high drainage and may be particularly vulnerable to increasing drought severity/events under climate change. This method is applicable to monitoring peatland resilience elsewhere over larger scales, and could be used to target restoration work towards the most vulnerable areas.

AUTOMATED FUEL DESIGN OPTIMIZATION FOR HIGH FLUX ISOTOPE REACTOR LOW ENRICHED URANIUM CORE DESIGN

The low enriched uranium (LEU) conversion project for the High Flux Isotope Reactor (HFIR) requires that the converted core design perform as well as or better than the current high enriched uranium core design with respect to key performance metrics, such as isotope production, while maintaining sufficient safety margins. Various designs and fuel shapes have been explored in previous optimization studies. A suite of scripts has been developed for HFIR LEU design and analysis to simplify the reactor physics and thermal hydraulics (TH) analyses. The scripts include generating a high-fidelity 3D HFIR model to perform core depletion simulations with the SHIFT Monte Carlo code, performing an essential rod criticality search during depletion, parsing SHIFT output to determine HFIR key metrics, and performing TH analysis with the HFIR Steady-State Heat Transfer Code. Previously, these scripts were separated and required human interaction between simulation stages. These scripts have been modernized and integrated into a single Python package (the Python HFIR Analysis and Measurement Engine or PHAME) to streamline execution and avoid potential human error. After modernizing the suite of scripts into a single, automated workflow, the tool set was wrapped into an in-house metaheuristic optimization driver that enables different optimization methods, such as simulated annealing and particle swarm. The optimization driver samples a fuel shape, runs PHAME, calculates the cost function with the metrics returned from PHAME, and repeats those steps until it finds an optimal fuel shape. This work demonstrates the workflow of a comprehensive, automated reactor design study and how metaheuristic optimization methods can be leveraged to fine-tune a design parameter like fuel shape. This workflow of wrapping an optimization driver on a full-scale reactor analysis suite increases design and analysis efficiency.

CONCEPTUAL FUEL ELEMENT DESIGN CANDIDATES FOR CONVERSION OF HIGH FLUX ISOTOPE REACTOR WITH LOW-ENRICHED URANIUM SILICIDE DISPERSION FUEL*

Engineering design studies are underway to assess the feasibility of converting the High Flux Isotope Reactor (HFIR) to operate with low-enriched uranium silicide dispersion (LEU3Si2-Al) fuel. These studies are supported by the U.S. Department of Energy National Nuclear Security Administration’s Office of Material Management and Minimization. A systematic approach employing neutronic and thermal-hydraulic analyses has been performed with the ORNL Shift and HFIR Steady State Heat Transfer Code tools, respectively, to predict reactor performance and thermal safety margins for proposed LEU3Si2-Al fuel designs. The design process was initiated by generating an optimized design with fabrication features identified from previous studies that result in excellent performance and safety metrics. The approach continued by substituting a single fabrication feature anticipated to be difficult to manufacture with another feature expected to perform an analogous function to that of the removed feature. Four conceptual fuel element design candidates, with various fabrication features, for conversion of HFIR with 4.8 gU/cm3 LEU3Si2-Al fuel have been generated and shown to meet pre-defined performance and safety metrics. Results to date indicate that HFIR could convert with the subject fuel system and meet performance and safety requirements if, among other considerations, fabrication of the specific design features are demonstrated and qualification of the fuel is complete under HFIR-specific conditions.

REACTOR PERFORMANCE IMPROVEMENT OPTIONS TO SUSTAIN HIGH FLUX ISOTOPE REACTOR LEADERSHIP INTO THE FUTURE*

The mission of the Neutron Sciences Directorate (NScD) at the U.S. Department of Energy’s Oak Ridge National Laboratory (ORNL) is the undertaking of high-impact research into the structure and properties of materials across the spectrum of biology, chemistry, physics, materials science, and engineering. NScD operates two world-leading neutron scattering facilities: the High Flux Isotope Reactor (HFIR) and the Spallation Neutron Source. HFIR achieved full power in 1966, and over a half century later, it continues to serve a variety of national missions. HFIR provides one of the highest steady-state neutron fluxes of any research reactor in the world to support scientific missions including cold and thermal neutron scattering, isotope production, and materials irradiation research. To sustain leadership in neutron sciences into the future, ORNL is exploring areas in which HFIR can be improved to enhance its performance. Many improvement areas are being explored including upgrading the cold source and neutron scattering facilities. The improvement areas discussed herein include replacing the reactor pressure vessel, upgrading the neutron reflector, and ensuring that reactor performance is maintained or enhanced after converting from high-enriched uranium to low-enriched uranium fuel.

Views of oral antibiotics and advice seeking about acne: a qualitative study of online discussion forums

BACKGROUND

Acne vulgaris is common and can significantly impair quality of life, yet little is known about patients' understanding of acne and its treatments. Oral antibiotics are widely used for acne despite concerns about antibiotic resistance. People are increasingly turning to online discussion forums for advice, and information on these sites may influence health beliefs and treatment adherence.

OBJECTIVES

To explore understandings about the use of oral antibiotics for acne and advice shared among messages posted on online forums.

METHODS

We systematically searched for online forums and identified four where acne was frequently discussed. Discussion threads relating to oral antibiotics were analysed thematically.

RESULTS

We extracted 136 pages of data comprising 65 discussions among 294 participants. We found a wide range of perceptions around effectiveness of antibiotics for acne and concerns about adverse effects. The delayed onset of action of antibiotics was a source of frustration and compounded dissatisfaction with healthcare providers, who were perceived by people as 'fobbing them off' with prolonged courses of ineffective treatment. Advice ranged from when to ask for or insist on referral to use of costly cleansers. Forum posts related to a wide range of severities, from 'spots' to severe acne, which may make it confusing for users to assess appropriateness of information.

CONCLUSIONS

Online forums offer opinions that could confuse patients, or lead to early abandonment of treatments, challenging consultations and patient dissatisfaction. Users expressed frustration about the delayed onset of action of antibiotics for acne, perceptions of only temporary effectiveness and adverse effects.

Abstract P1-10-04: A prospective study of patterns of chemotherapy, colony-stimulating factor use, and burden of colony-stimulating factor injections in patients with early-stage breast cancer

Background: Febrile neutropenia (FN) is a common side effect of myelosuppressive chemotherapy. Primary prophylaxis with colony-stimulating factors (CSFs) can reduce FN incidence and is recommended when a patient has a high risk of FN (> 20%). In the prophylactic setting, CSFs should be administered at least 24 hours after chemotherapy completion. Patient burden associated with CSF administration is not well understood. Here we describe current patterns of chemotherapy use and burden of CSF injections for patients with early-stage breast cancer (ESBC) in US clinical practice.

Methods: This was a prospective cohort study of adult ESBC patients receiving their first chemotherapy course who had a high risk of FN based on high- or intermediate-risk chemotherapy regimen and individual FN risk factors. The burden associated with CSF injections was assessed via questionnaires among patients who received CSF, and a subset analysis of patient burden in the first cycle of chemotherapy is reported.

Results: 598 patients completed the "burden of CSF injections" questionnaire following the first cycle of chemotherapy. Most patients were < 65 years old (76.8%), had a BMI < 30 kg/m2 (54.9%), and had few comorbidities (see table for additional characteristics and comorbidities). The three most common chemotherapy regimens received were ddAC-T (34.4%), TC (23.4%), and TCH (15.6%). 98.3% of patients received prophylaxis with CSF in the first chemotherapy cycle: 94.6% of these received pegfilgrastim, and 5.4% received filgrastim. Among all patients who received CSF, mean (SD) one-way travel time for a single CSF injection was 31 (25) minutes; mean (SD) time in office to receive a CSF injection was 41 (68) minutes. Across the first chemotherapy cycle, mean (SD) time missed from work for CSF administration was 3.1 (9.3) hours, and mean (SD) time missed from non-work activities was 5.5 (14.4) hours. 66.3% of patients had someone else assist them with travel to the clinic to receive CSF, of which 98.8% were helped by an unpaid caregiver. When patients were questioned about the subjective burden of CSF injections, 25.4% reported some degree of bother, and 15.9% reported at least moderate inconvenience.

Conclusions: Among the high- and intermediate-risk regimens investigated here, dose-dense and taxane-based chemotherapy regimens were common. As many high-risk patients with ESBC receive primary prophylaxis with CSF, travel and time needed to receive CSF can contribute to patient and caregiver burden.

Patient CharacteristicsN = 598 Age, mean (SD) years55.1 (11.3) BMI, mean (SD) kg/m230.7 (7.5) HER2+23.2% Luminal Aa52.0% Triple negative21.6% Stage at diagnosis  124.6% 253.7% 321.2% Missing0.5%Comorbidities > 10% Hypertension37.5% Hyperlipidemia24.7% Depression13.9% Diabetes mellitus13.4% Osteoarthritis12.7% Gastroesophageal reflux disease12.2% Hypothyroidism12.0% Anxiety11.9%aHormone receptor positive but HER2 negative.

Citation Format: Li X, Barron R, Tzivelekis S, Li Y, Chandler D, Xu H, Morrow PK, Klippel Z, Nagarajan A, Reiner M, Page JH. A prospective study of patterns of chemotherapy, colony-stimulating factor use, and burden of colony-stimulating factor injections in patients with early-stage breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-10-04.

Predicting imminent risk for fracture in patients aged 50 or older with osteoporosis using US claims data

Patient characteristics contributing to imminent risk for fracture, defined as risk of near-term fracture within the next 12 to 24 months, have not been well defined. In patients without recent fracture, we identified factors predicting imminent risk for vertebral/nonvertebral fracture, including falls, age, comorbidities, and other potential fall risk factors.

PURPOSE

Several factors contribute to long-term fracture risk in patients with osteoporosis, including age, bone mineral density, and fracture history. Some patients may be at imminent risk for fracture, defined here as a risk of near-term fracture within 12-24 months. Many patient characteristics contributing to imminent risk for fracture have not been well defined. This case-control study used US commercial and Medicare supplemental insured data for women and men without recent fracture to identify factors associated with imminent risk for fracture.

METHODS

Patients included were aged ≥50 with osteoporosis, had a vertebral or nonvertebral fracture claim (index date; fracture group) or no fracture claim (control group) from January 1, 2006, to September 30, 2012, continuously enrolled and without fracture in the 24 months before index. Potential risk factors during the period before fracture were assessed.

RESULTS

Using data from 12 months before fracture, factors significantly associated with imminent risk for fracture were previous falls, older age, poorer health status, specific comorbidities (psychosis, Alzheimer's disease, central nervous system disease), and other fall risk factors (wheelchair use, psychoactive medication use, mobility impairment). Similar findings were observed with data from 24 months before fracture.

CONCLUSIONS

In patients with osteoporosis and no recent fracture, falls, older age, poorer health status, comorbidities, and other potential fall risk factors were predictive of imminent risk for fracture. Identification of factors associated with imminent risk for vertebral/nonvertebral fracture may help identify and risk stratify those patients most in need of immediate and appropriate treatment to decrease fracture risk.

Patterns of treatment among a cohort of older low-income adults starting new medications for osteoporosis

Among 125,954 new users of osteoporosis (OP) medications, 77 % of subjects stopped OP medications, and 23 % of subjects added or started a new OP medication during follow-up, with the first addition or start of a new OP medication occurring in a mean of 739 days after original OP treatment.

INTRODUCTION

We described patterns and predictors of OP medication use, focusing on treatment changes over time.

METHODS

We analyzed health and pharmacy insurance claims for a large cohort of low-income Medicare beneficiaries with a drug benefit for the years 1998-2008. Study subjects had documented Medicare claims and no receipt of OP medications (i.e., bisphosphonate, raloxifene, calcitonin, teriparatide, or hormonal therapy) during a baseline of 180 days. Subjects were then required to start an OP medication. Baseline patient and prescriber characteristics were assessed in multivariable Cox regression models to identify correlates of adding or starting a new OP medication. Fractures, bone mineral density testing, and visits with endocrinologists or rheumatologists occurring after baseline were also examined as correlates.

RESULTS

We included 125,954 new users of OP medications with a mean age of 78 years, 97 % female, and 92 % white. OP medication prescribers included specialists (i.e., endocrinologists or rheumatologists) (6.2 %), orthopedic surgeons (1.0 %), primary care providers (64.9 %), other physicians (3.7 %), and missing (24.1 %). Seventy-seven percent of subjects stopped OP medications, and 23 % of subjects added or started a new OP medication during follow-up, with the first addition or start of a new OP medication occurring in a mean of 739 days after original OP treatment; 4 % added or started a new OP medication more than once. In fully adjusted models, many baseline variables correlated with starting a second OP medication. Post-baseline fractures [hazard ratio (HR) 1.76, 95 % confidence interval (CI) 1.71-1.82] and bone mineral density testing (HR 2.94, 95 % CI 2.86-3.03) were strong predictors.

CONCLUSION

Approximately one quarter of patients starting an OP medication added or started a new OP medication during follow-up. Long-term sequential treatment strategy trials would inform optimal medication treatment for OP.

Sex-specific time trends in first admission to hospital for peripheral artery disease in Scotland 1991–2007

Background

This study examined trends for all first hospital admissions for peripheral artery disease (PAD) in Scotland from 1991 to 2007 using the Scottish Morbidity Record.

Methods

First admissions to hospital for PAD were defined as an admission to hospital (inpatient and day-case) with a principal diagnosis of PAD, with no previous admission to hospital (principal or secondary diagnosis) for PAD in the previous 10 years.

Results

From 1991 to 2007, 41 593 individuals were admitted to hospital in Scotland for the first time for PAD. Some 23 016 (55·3 per cent) were men (mean(s.d.) age 65·7(11·7) years) and 18 577 were women (aged 70·4(12·8) years). For both sexes the population rate of first admissions to hospital for PAD declined over the study interval: from 66·7 per 100 000 in 1991-1993 to 39·7 per 100 000 in 2006-2007 among men, and from 43·5 to 29·1 per 100 000 respectively among women. After adjustment, the decline was estimated to be 42 per cent in men and 27 per cent in women (rate ratio for 2007 versus 1991: 0·58 (95 per cent confidence interval 0·55 to 0·62) in men and 0·73 (0·68 to 0·78) in women). The intervention rate fell from 80·8 to 74·4 per cent in men and from 77·9 to 64·9 per cent in women. The proportion of hospital admissions as an emergency or transfer increased, from 23·9 to 40·7 per cent among men and from 30·0 to 49·5 per cent among women.

Conclusion

First hospital admission for PAD in Scotland declined steadily and substantially between 1991 and 2007, with an increase in the proportion that was unplanned.

Neuregulin 3 (NRG3) as a susceptibility gene in a schizophrenia subtype with florid delusions and relatively spared cognition

Linkage of 10q22-q23 to schizophrenia and the recently reported association of Neuregulin 3 (NRG3) polymorphisms with high 'delusion factor' scores led us to attempt replication and further refinement of these findings in a sample of 411 schizophrenic patients and 223 nonpsychiatric control subjects. Using quantitative cognitive traits, patients were grouped into a cluster with pervasive cognitive deficit (CD) and a cluster with relatively spared cognition (CS). We found a significant association between rs6584400 and schizophrenia, with a trend for rs10883866. Post hoc analysis revealed that this result was mainly due to the CS cluster, characterized by elevated scores on Schneiderian first-rank symptoms, salience of complex delusions and positive thought disorder--thus closely related to the 'delusion factor'. In addition, both rs6584400 and rs10883866 were associated with the degraded-stimulus continuous performance task in which 'risk' alleles were associated with better than average performance in patients and worse performance in controls. This suggests that NRG3 may be modulating early attentional processes for perceptual sensitivity and vigilance, with opposite effects in affected individuals and healthy controls. The two single-nucleotide polymorphisms are in close proximity to the alternative first exons of the NRG3-a, -b and -d isoforms, of which the human brain-specific NRG-b appears to be the most interesting candidate.

Polymorphisms associated with normal memory variation also affect memory impairment in schizophrenia

Neurocognitive dysfunction is a core feature of schizophrenia with particularly prominent deficits in verbal episodic memory. The molecular basis of this memory impairment is poorly understood and its relatedness to normal variation in memory performance is unclear. In this study, we explore, in a sample of cognitively impaired schizophrenia patients, the role of polymorphisms in seven genes recently reported to modulate episodic memory in normal subjects. Three polymorphisms (GRIN2B rs220599, GRM3 rs2189814 and PRKCA rs8074995) were associated with episodic verbal memory in both control and patients with cognitive deficit, but not in cognitively spared patients or the pooled schizophrenia sample. GRM3 and PRKCA acted in opposite directions in patients compared to controls, possibly reflecting an abnormal brain milieu and/or adverse environmental effects in schizophrenia. The encoded proteins balance glutamate signalling vs. excitotoxicity in complex interactions involving the excitatory amino acid transporter 2 (EAAT2), implicated in the dysfunctional glutamatergic signalling in schizophrenia. Double carrier status of the GRM3 and PRKCA minor alleles was associated with lower memory test scores and with increased risk of schizophrenia. Single nucleotide polymorphism (SNP) rs8074995 lies within the PRKCA region spanned by a rare haplotype associated with schizophrenia in a recent UK study and provides further evidence of PRKCA contribution to memory impairment and susceptibility to schizophrenia. Our study supports the utility of parsing the broad phenotype of schizophrenia into component cognitive endophenotypes that reduce heterogeneity and enable the capture of potentially important genetic associations.

Dynamics affecting the primary charge transfer in photosynthesis

Analysis of a 60-picosecond molecular dynamics trajectory of the reaction center of Rhodopseudomonas viridis provides an understanding of observations concerning vibrational coherence and the nonexponential kinetics of the primary charge transfer in photosynthesis. Complex kinetics arises from energy gap correlations that persist beyond 1 picosecond.

Van der waals picture of liquids, solids, and phase transformations

The van der Waals picture focuses on the differing roles of the strong short-ranged repulsive intermolecular forces and the longer ranged attractions in determining the structure and dynamics of dense fluids and solids. According to this physical picture, the attractive interactions help fix the volume of the system, but the arrangements and motions of molecules within that volume are determined primarily by the local packing and steric effects produced by the repulsive forces. This very useful approach, its limitations, and its successful application to a wide variety of static and dynamic phenomena in condensed matter systems are reviewed.

Differential effect of Agaricus host species on the population development of Megaselia halterata (Diptera: Phoridae)

Twelve isolates from the genus Agaricus (Fungi, Basidiomycota) were investigated for their ability to support development of the phorid fly, Megaselia halterata (Wood), which is an important pest of the commercial white button mushroom Agaricus bisporus. Combined effects of oviposition of adult female M. halterata and larval development in mushroom compost inoculated with Agaricus mycelium were determined using bioassays. The numbers of M. halterata offspring that developed were affected by the Agaricus isolate used, and there was a significant separation between resistant and susceptible isolates. In a bioassay where the female phorids had a choice of all 12 isolates for oviposition, three isolates produced >200 adults per 100 g compost pot while the remaining nine isolates had <20 adults per pot. Where there was no choice of Agaricus isolate for oviposition, five isolates resulted in >100 adults per 100 g compost pot while the remainder resulted in <4 adults per pot. With the susceptible isolates, there was a positive correlation between increasing concentration of mycelium in the substrate and phorid development until the concentration exceeded 40% after which numbers of emerging phorids declined. Genetic identity of Agaricus isolates was determined using ITS sequencing and phylogenetic methods, which revealed two major cluster groups. Isolates supporting the development of large populations of M. halterata were located in one of these clusters (group I), and were either Agaricus bisporus or other species from the same Agaricus section Duploannulatae. Isolates that did not support the development of M. halterata populations were located in a different cluster (group II) and were more genetically distant from A. bisporus, e.g. Agaricus sections Arvenses, Minores and Xanthodermatei. Species of Agaricus with resistance to M. halterata could have significant potential for the breeding and cultivation of phorid-free mushrooms.

Development of a population-based threshold model of conidial germination for analysing the effects of physiological manipulation on the stress tolerance and infectivity of insect pathogenic fungi

Entomopathogenic fungi are being used as biocontrol agents of insect pests, but their efficacy can be poor in environments where water availability is reduced. In this study, the potential to improve biocontrol by physiologically manipulating fungal inoculum was investigated. Cultures of Beauveria bassiana, Lecanicillium muscarium, Lecanicillium longisporum, Metarhizium anisopliae and Paecilomyces fumosoroseus were manipulated by growing them under conditions of water stress, which produced conidia with increased concentrations of erythritol. The time-course of germination of conidia at different water activities (water activity, aw) was described using a generalized linear model, and in most cases reducing the water activity of the germination medium delayed the onset of germination without affecting the distribution of germination times. The germination of M. anisopliae, L. muscarium, L. longisporum and P. fumosoroseus was accelerated over a range of aw levels as a result of physiological manipulation. However, the relationship between the effect of physiological manipulation on germination and the osmolyte content of conidia varied according to fungal species. There was a linear relationship between germination rate, expressed as the reciprocal of germination time, and aw of the germination medium, but there was no significant effect of fungal species or physiological manipulation on the aw threshold for germination. In bioassays with M. anisopliae, physiologically manipulated conidia germinated more rapidly on the surface of an insect host, the melon cotton aphid Aphis gossypii, and fungal virulence was increased even when relative humidity was reduced after an initial high period. It is concluded that physiological manipulation may lead to improvements in biocontrol in the field, but choice of fungal species/isolate will be critical. In addition, the population-based threshold model used in this study, which considered germination in terms of physiological time, also called hydrotime, could have general application in mycology and environmental microbiology.

A novel Gypsy founder mutation, p.Arg1109X in the CMT4C gene, causes variable peripheral neuropathy phenotypes

BACKGROUND

Linkage, haplotype and sequencing analysis in a large Spanish Gypsy kindred with multiple members affected by autosomal recessive peripheral neuropathy led to the identification of a novel mutation, p.Arg1109X, in the CMT4C gene. The screening of further unrelated patients, and of a panel of ethnically matched controls, showed that p.Arg1109X is an ancestral mutation which occurs in Gypsy populations across Europe and is the most common cause of autosomal recessive Charcot-Marie-Tooth disease in Spanish Gypsies.

OBJECTIVE

To report the identification of a novel Gypsy founder mutation causing autosomal recessive CMT4C disease in a sample of homozygous affected individuals.

RESULTS

The mutation was associated with a surprisingly broad spectrum of neuropathy phenotypes, with variation in the age at onset, rate of progression, severity of muscle and sensory involvement, the presence of scoliosis, and cranial nerve involvement.

CONCLUSIONS

Ascertainment and further studies of CMT4C patients in this population will provide a unique opportunity for characterising the full range of clinical manifestations of the disease in a genetically homogeneous sample.

Synergism of rotenone by piperonyl butoxide in Haemonchus contortus and Trichostrongylus colubriformis in vitro: potential for drug-synergism through inhibition of nematode oxidative detoxification pathways

The anthelmintic properties of rotenone and its activity in combination with the cytochrome P450 inhibitor piperonyl butoxide, were examined in in vitro assays with adults and larvae of Haemonchus contortus and larvae of Trichostrongylus colubriformis. Rotenone was toxic to larvae of both species, with LC(50) values in larval development assays of 0.54 and 0.64 microg/ml for H. contortus and T. colubriformis, respectively. The compound also caused complete cessation of movement in adult H. contortus after 72 h at a concentration of 20 microg/ml. Toxicity of rotenone towards the larvae of both species was increased in the presence of piperonyl butoxide (synergism ratios of 3-4-fold at the LC(50)) and the activity against adult H. contortus was also significantly enhanced following pre-treatment with piperonyl butoxide. This significant synergism suggests that these nematode species are able to utilize a cytochrome P450 enzyme system to detoxify rotenone and indicates that a role may exist for cytochrome P450 inhibitors to act as synergists for other anthelmintics which are susceptible to oxidative metabolism within the nematode.

Evaluation of entomopathogenic fungus Metarhizium anisopliae against soil-dwelling stages of cabbage maggot (Diptera: Anthomyiidae) in glasshouse and field experiments and effect of fungicides on fungal activity

The effect of two isolates of the entomopathogenic fungus Metarhizium anisopliae (Metchnikoff) Sorokin (389.93 and 392.93) on root-feeding stages of cabbage root fly, Delia radicum (L.), was studied under glasshouse and field conditions. In glasshouse studies, the effect of drenching a suspension of conidia (concentration 1 x 10(8) m(-1), 40 ml per plant, applied on four occasions) onto the base of cabbage plants infested with D. radicum eggs was compared with mixing conidial suspension into compost modules (concentration 1 x 10(8) ml(-1), 25 ml per plant) used to raise seedlings. Drench application reduced the mean number of larvae and pupae recovered per plant by up to 90%, but the compost module treatment had no statistically significant effect. Both application methods reduced the emergence of adult flies from pupae by up to 92%. Most conidia applied as a drench application remained in the top 10-cm layer of compost. Applications of the fungicides iprodione and tebuconazole, which are used routinely on brassica crops, were compatible with using M. anisopliae 389.93 against D. radicum under glasshouse conditions, even though these fungicides were inhibitory to fungal growth on SDA medium. In a field experiment, drench applications of M. anisopliae 389.93 to the base of cauliflower plants at concentrations of 1 x 10(6) to 1 x 10(8) conidia ml(-1) did not control D. radicum populations, although up to 30% of larval cadavers recovered supported sporulating mycelium. Drench applications often exhibited considerable lateral movement on the soil surface before penetrating the ground, which may have reduced the amount of inoculum in contact with D. radicum larvae.

Laboratory evaluation of entomopathogenic fungi against larvae and adults of onion maggot (Diptera: Anthomyiidae)

Laboratory experiments were done to measure the susceptibility of larvae and adults of the onion maggot, Delia antiqua (Meigen) (Diptera: Muscidae: Anthomyiidae) to 27 isolates of entomopathogenic fungi from four genera [Beauveria Vuillemin, Lecanicillium (Petch) Zare & W. Gams, Metarhizium Sorokin, and Paecilomyces Bainier]. A novel bioassay was developed for D. antiqua larvae by using a diet based on mixed vegetable powder. When evaluated in a virulence screen, the fungal isolates caused less mortality of D. antiqua larvae than adults. Only three isolates caused > 50% mortality of larvae, whereas 12 isolates caused > 50% mortality of adults. Fungal species was a statistically significant factor affecting the mortality of larvae but not of adults. The fungal isolates causing the most mortality of larvae tended to belong to Metarhizium anisopliae (Metschnikoff) Sorokin. Two M. anisopliae isolates (389.93 and 392.93) were evaluated in dose-response bioassays. The median lethal concentrations of the isolates against larvae were 6.1 x 10(7) conidia ml(-1) for isolate 389.93 and 7.6 x 10(7) conidia ml(-1) for isolate 392.93. The emergence of adult flies from pupae was reduced at high concentrations of conidia (3.0 x 10(8) and 1.0 x 10(8) conidia ml(-1)). The median lethal concentrations of the isolates against adults were 1.7 x 10(7) and 4.0 x 10(7) conidia ml(-1), respectively. Some of the fungal isolates examined may have potential as biological control agents of larvae of D. antiqua and related species.

Study of temperature-growth interactions of entomopathogenic fungi with potential for control of Varroa destructor (Acari: Mesostigmata) using a nonlinear model of poikilotherm development

AIMS

To investigate the thermal biology of entomopathogenic fungi being examined as potential microbial control agents of Varroa destructor, an ectoparasite of the European honey bee Apis mellifera.

METHODS AND RESULTS

Colony extension rates were measured at three temperatures (20, 30 and 35 degrees C) for 41 isolates of entomopathogenic fungi. All of the isolates grew at 20 and 30 degrees C but only 11 isolates grew at 35 degrees C. Twenty-two isolates were then selected on the basis of appreciable growth at 30-35 degrees C (the temperature range found within honey bee colonies) and/or infectivity to V. destructor, and their colony extension rates were measured at 10 temperatures (12.5-35 degrees C). This data were then fitted to Schoolfield et al. [J Theor Biol (1981)88:719-731] re-formulation of the Sharpe and DeMichele [J Theor Biol (1977)64:649-670] model of poikilotherm development. Overall, this model accounted for 87.6-93.9% of the data variance. Eleven isolates exhibited growth above 35 degrees C. The optimum temperatures for extension rate ranged from 22.9 to 31.2 degrees C. Only three isolates exhibited temperature optima above 30 degrees C. The super-optimum temperatures (temperature above the optimum at which the colony extension rate was 10% of the maximum rate) ranged from 31.9 to 43.2 degrees C.

CONCLUSIONS

The thermal requirements of the isolates examined against V. destructor are well matched to the temperatures in the broodless areas of honey bee colonies, and a proportion of isolates, should also be able to function within drone brood areas.

SIGNIFICANCE AND IMPACT OF THE STUDY

Potential exists for the control of V. destructor with entomopathogenic fungi in honey bee colonies. The methods employed in this study could be utilized in the selection of isolates for microbial control prior to screening for infectivity and could help in predicting the activity of a fungal control agent of V. destructor under fluctuating temperature conditions.

Efficient transition path sampling for nonequilibrium stochastic dynamics

The transition path sampling methodology is adapted to the efficient sampling of large fluctuations in nonequilibrium systems evolving according to Langevin's equations of motion. This technique is used to simulate the behavior of the bistable Maier-Stein system at noise intensities much lower than those previously possible.

Molecular cloning of three cDNAs encoding aminopeptidases from the midgut of Helicoverpa punctigera, the Australian native budworm

Three cDNAs encoding aminopeptidases HpAPN1, HpAPN2 and HpAPN3, were isolated from a 5th instar larval midgut cDNA library from Helicoverpa punctigera, the Australian native budworm. The sequences recovered contain open reading frames encoding proteins of 1011, 952, and 1013 amino acids, respectively. All three proteins share the consensus zinc binding/gluzincin motif HEXXHX(18)E and the sequence GAMEN common to gluzincin aminopeptidases. Furthermore, signal peptide sequences and C-terminal hydrophobic regions preceded by three small amino acids qualifying for cleavage and GPI anchor attachment are present in all three protein sequences. Northern blotting results indicate differences in the levels of expression and developmental regulation of all three aminopeptidases. HpAPN1, HpAPN2, and HpAPN3 are more closely related to APNs from other lepidopterans than they are to each other. This report of three different aminopeptidases N in Helicoverpa punctigera adds support to a recent suggestion that at least one gene duplication has taken place in ancestral lepidopterans. The full sequences of the aminopeptidases are available at GENBANK with the following accession numbers: HpAPN1: AF217248, HpAPN2: AF217249, HpAPN3: AF217250.

Refinement of the chromosome 5p locus for craniometaphyseal dysplasia

Craniometaphyseal dysplasia--Jackson type (CMDJ) is an autosomal dominant bone dysplasia with hyperostosis and sclerosis of the skull and abnormal modelling of the metaphyses. In a large German pedigree, a locus for CMDJ has been mapped previously to the short arm of chromosome 5 (5p15.2-p14.1), defining a 19-cM disease interval between markers D5S2004 and D5S502. Analysis of a large Australian pedigree together with a second German family confirms linkage to the same region. Obligate recombinations in the new families and confirmation of a supposed recombination in the previously reported German kindred have enabled us to narrow the critical region down to approximately 4 cM between markers D5S1987 and D5S1991.

Heterozygous mutations in ANKH, the human ortholog of the mouse progressive ankylosis gene, result in craniometaphyseal dysplasia

Craniometaphyseal dysplasia (CMD) is a bone dysplasia characterized by overgrowth and sclerosis of the craniofacial bones and abnormal modeling of the metaphyses of the tubular bones. Hyperostosis and sclerosis of the skull may lead to cranial nerve compressions resulting in hearing loss and facial palsy. An autosomal dominant form of the disorder (MIM 123000) was linked to chromosome 5p15.2-p14.1 (ref. 3) within a region harboring the human homolog (ANKH) of the mouse progressive ankylosis (ank) gene. The ANK protein spans the outer cell membrane and shuttles inorganic pyrophosphate (PPi), a major inhibitor of physiologic and pathologic calcification, bone mineralization and bone resorption. Here we carry out mutation analysis of ANKH, revealing six different mutations in eight of nine families. The mutations predict single amino acid substitutions, deletions or insertions. Using a helix prediction program, we propose for the ANK molecule 12 membrane-spanning helices with an alternate inside/out orientation and a central channel permitting the passage of PPi. The mutations occur at highly conserved amino acid residues presumed to be located in the cytosolic portion of the protein. Our results link the PPi channel ANK with bone formation and remodeling.

Autoionization in liquid water

The dissociation of a water molecule in liquid water is the fundamental event in acid-base chemistry, determining the pH of water. Because of the short time scales and microscopic length scales involved, the dynamics of this autoionization have not been directly probed by experiment. Here, the autoionization mechanism is revealed by sampling and analyzing ab initio molecular dynamics trajectories. We identify the rare fluctuations in solvation energies that destabilize an oxygen-hydrogen bond. Through the transfer of protons along a hydrogen bond "wire," the nascent ions separate by three or more neighbors. If the hydrogen bond wire connecting the two ions is subsequently broken, a metastable charge-separated state is visited. The ions may then diffuse to large separations. If, however, the hydrogen bond wire remains unbroken, the ions recombine rapidly. Because of their concomitant large electric fields, the transient ionic species produced in this case may provide an experimentally detectable signal of the dynamics we report.

Autoionization in liquid water

The dissociation of a water molecule in liquid water is the fundamental event in acid-base chemistry, determining the pH of water. Because of the short time scales and microscopic length scales involved, the dynamics of this autoionization have not been directly probed by experiment. Here, the autoionization mechanism is revealed by sampling and analyzing ab initio molecular dynamics trajectories. We identify the rare fluctuations in solvation energies that destabilize an oxygen-hydrogen bond. Through the transfer of protons along a hydrogen bond "wire," the nascent ions separate by three or more neighbors. If the hydrogen bond wire connecting the two ions is subsequently broken, a metastable charge-separated state is visited. The ions may then diffuse to large separations. If, however, the hydrogen bond wire remains unbroken, the ions recombine rapidly. Because of their concomitant large electric fields, the transient ionic species produced in this case may provide an experimentally detectable signal of the dynamics we report.

Hereditary motor and sensory neuropathy--Lom (HMSNL): refined genetic mapping in Romani (Gypsy) families from several European countries

Hereditary motor and sensory neuropathy type Lom, initially identified in Roma (Gypsy) families from Bulgaria, has been mapped to 8q24. Further refined mapping of the region has been undertaken on DNA from patients diagnosed across Europe. The refined map consists of 25 microsatellite markers over approximately 3 cM. In this collaborative study we have identified a number of historical recombinations resulting from the spread of the hereditary motor and sensory neuropathy type Lom gene through Europe with the migration and isolation of Gypsy groups. Recombination mapping and the minimal region of homozygosity reduced the original 3 cM hereditary motor and sensory neuropathy type Lom region to a critical interval of about 200 kb.

Dielectric response of a polarizable system with quenched disorder

We present and analyze a lattice model of a disordered dielectric material. In the model, the local polarizability is a quenched statistical variable. Using a reaction field approach, the dielectric response of the model can be cast in terms of an effective Hamiltonian for a finite primary system coupled to its effective average medium determined self-consistently. A real space renormalization group analysis is carried out by recursively increasing the size of the primary system. The analysis determines the length scale dependence of the local polarizability distribution. For the case of isotropic disorder considered in this paper, we show that the width of the distribution decays algebraically with increasing lattice spacing. We also compute the distribution of solvation and reorganization energies pertinent to kinetics of electron transfer.

Polarizability fluctuations in dielectric materials with quenched disorder

We study a model of dielectric response for spatially disordered materials. In this model the local polarizability alpha(r) is a quenched random variable. From a one-loop level renormalization-group analysis, we predict that with increasing length scale L, the dimensionless fluctuation strength alpha;sigma, where 1/alpha; and sigma(2) are the average and the variance of the distribution for 1/alpha(r), decays as 1/L(2) universally at large length scales. The interplay of the random polarizability and the long-range dipole-dipole interaction is discussed.

A novel locus for autosomal recessive peripheral neuropathy in the EGR2 region on 10q23

During our studies of Romany (Gypsy) families with hereditary motor and sensory neuropathy-Lom, we have identified a large kindred with two independently segregating autosomal recessive neuropathies. The novel disorder, named "hereditary motor and sensory neuropathy-Russe" (HMSNR), presented as a severe disabling form of Charcot-Marie-Tooth disease with prominent sensory loss, moderately reduced motor nerve conduction velocity, and a high threshold for electrical nerve stimulation. A genome scan in two branches of the large kindred detected linkage to the 10q22-q23 region containing the early growth response 2 gene (EGR2), a transcription factor with a key role in peripheral nerve myelination. The results of sequence analysis and the detection of an intragenic polymorphism allowed us to exclude EGR2 as the HMSNR gene. Further analysis done using linkage and recombination mapping refined the position of the HMSNR gene to a small interval on 10q23.2, flanked by markers D10S581 and D10S1742, telomeric to EGR2. In this interval, a conserved seven-marker haplotype is shared by all disease chromosomes, suggesting a single founder mutation. The homozygosity region is contained in bacterial-artificial-chromosome contig 1570 of the Sanger Centre physical map and has an estimated physical size of approximately 500 kb.

Temperature and length scale dependence of hydrophobic effects and their possible implications for protein folding

The Lum-Chandler-Weeks theory of hydrophobicity [Lum, K., Chandler, D. & Weeks, J. D. (1999) J. Phys. Chem. 103, 4570-4577] is applied to treat the temperature dependence of hydrophobic solvation in water. The application illustrates how the temperature dependence for hydrophobic surfaces extending less than 1 nm differs significantly from that for surfaces extending more than 1 nm. The latter is the result of water depletion, a collective effect, that appears at length scales of 1 nm and larger. Because of the contrasting behaviors at small and large length scales, hydrophobicity by itself can explain the variable behavior of entropies of protein folding.

N-myc downstream-regulated gene 1 is mutated in hereditary motor and sensory neuropathy-Lom

Hereditary motor and sensory neuropathies, to which Charcot-Marie-Tooth (CMT) disease belongs, are a common cause of disability in adulthood. Growing awareness that axonal loss, rather than demyelination per se, is responsible for the neurological deficit in demyelinating CMT disease has focused research on the mechanisms of early development, cell differentiation, and cell-cell interactions in the peripheral nervous system. Autosomal recessive peripheral neuropathies are relatively rare but are clinically more severe than autosomal dominant forms of CMT, and understanding their molecular basis may provide a new perspective on these mechanisms. Here we report the identification of the gene responsible for hereditary motor and sensory neuropathy-Lom (HMSNL). HMSNL shows features of Schwann-cell dysfunction and a concomitant early axonal involvement, suggesting that impaired axon-glia interactions play a major role in its pathogenesis. The gene was previously mapped to 8q24.3, where conserved disease haplotypes suggested genetic homogeneity and a single founder mutation. We have reduced the HMSNL interval to 200 kb and have characterized it by means of large-scale genomic sequencing. Sequence analysis of two genes located in the critical region identified the founder HMSNL mutation: a premature-termination codon at position 148 of the N-myc downstream-regulated gene 1 (NDRG1). NDRG1 is ubiquitously expressed and has been proposed to play a role in growth arrest and cell differentiation, possibly as a signaling protein shuttling between the cytoplasm and the nucleus. We have studied expression in peripheral nerve and have detected particularly high levels in the Schwann cell. Taken together, these findings point to NDRG1 having a role in the peripheral nervous system, possibly in the Schwann-cell signaling necessary for axonal survival.

Reaction coordinates of biomolecular isomerization

Transition path sampling has been applied to the molecular dynamics of the alanine dipeptide in vacuum and in aqueous solution. The analysis shows that more degrees of freedom than the traditional dihedral angles, phi and psi, are necessary to describe the reaction coordinates for isomerization of this molecule. In vacuum, an additional dihedral angle is identified as significant. In solution, solvent variables are shown to play a significant role, and this role appears to be more specific than can be captured by friction models. Implications for larger molecules are discussed.