Toxicity in patients (pts) age 65 or older with dose-adjusted REPOCH (DA-REPOCH) for untreated diffuse large B-cell lymphoma (DLBCL)

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Background: ORR of 97-99% and 5-yr PFS of 75-79% are reported with front-line DA-REPOCH in pts age 19-85. In these prospective series, 72% of pts escalated ≥ 1 dose level (DL), febrile neutropenia (FN) occurred in 36-51% pts, and 3-4% died of toxicity. Methods: We performed retrospective analysis of pts ≥ 65 treated with DA-REPOCH front-line for DLBCL at Ohio State University from 2002-2011. PFS estimates were calculated by the Kaplan-Meier method. Logistic regression and proportional hazards models were fit to identify variables associated with ORR and PFS, respectively. Results: 69 pts ≥ 65 yrs (range, 65-92) received DA-REPOCH for de novo (n=42) or transformed (prior CLL=16, FL=9, HL=2) DLBCL, including 28 pts ≥ 75. Performance status (PS) was ≥ 2 in 43%, 86% were stage III-IV, 77% had an aaIPI ≥ 2, 19% had bulky disease ≥ 10 cm, 83% had extranodal disease, and median creatinine clearance (CrCl) was 64 ml/min. Median number of cycles was 5 (range 1-7). Max DL was 1, 2, and 3 in 72, 13, and 6% of pts, respectively, and 9% received all cycles below DL 1. Max DL and number of cycles were similar between pts 65-74 and > 75. Dose reductions (DR), delays, FN, and hospitalization occurred in 48, 39, 38, and 42% of pts, respectively. DR were associated with age ≥ 75 (p=0.001) or reduced CrCl (p=0.02) and delays strongly associated with PS ≥ 2 (p=0.001). FN was associated with bulky disease (p=0.03); 31% of pts without bulky disease developed FN compared to 67% with bulk. Nine pts (13%, 3 pts ≥ 75) died of toxicity (7 pts at DL 1 and 2 at DL < 1). ORR was 67% (95% CI 52-75%). Median PFS was 17 mos (95% CI 6-43). Increased LDH (p=0.008 and p<0.001) and number of prior chemotherapies (p=0.04 and p<0.001) were independently predictive for ORR and PFS, respectively. DR and age were not associated with ORR or PFS, controlling for LDH and number of prior regimens. In 42 pts with de novo DLBCL, ORR was 71% (95% CI 54-85%) and median PFS was 36 mos (95% CI 7-94). Conclusions: In this retrospective study, toxicity is increased with DA-REPOCH in pts ≥ 65 with DLBCL, compared to published results in a younger population. Age ≥ 75, impaired CrCl, and poor PS are associated with increased risk of DR and delays, although age and DR do not appear to impact ORR and PFS.

A phase Ib/II study evaluating activity and tolerability of BTK inhibitor PCI-32765 and ofatumumab in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and related diseases

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Background: Bruton’s tyrosine kinase (BTK) is a non-receptor kinase that is critical for B-cell receptor (BCR) signaling in normal and malignant B lymphocytes. PCI-32765 (P), an oral, potent and irreversible BTK inhibitor, antagonizes BCR signaling in CLL cells and abrogates protective features of the microenvironment. P is highly active as a single agent in CLL/SLL patients (pts), and this phase Ib/II study builds upon single-agent experience by combining P with ofatumumab (O), an anti-CD20 monoclonal antibody. We present initial safety and efficacy data from cohort 1. Methods: Pts with relapsed/refractory (R/R) CLL/SLL following ≥2 prior therapies (Tx), including a purine-nucleoside analog (PA), are treated with 420 mg P daily, in 28-day cycles, until disease progression. O is added at a dose of 300 mg on day (D) 1 of cycle 2, followed by 2000 mg on D8, 15, and 22 of cycle 2, D1, 8, 15, and 22 of cycle 3, and on D1 of cycles 5-8. Results: As of November 2011, 27 patients with either CLL/SLL/PLL (n=24) or Richter’s transformation (RT, n=3) have been enrolled and have received at least 6 cycles of treatment. The median age is 66 (range 51-85), 9 were Rai stage III/IV. Median number of prior Tx is 3 (range 2-10), 15 pts had bulky disease (> 5 cm); 11 pts were PA refractory. Poor-risk molecular features were common (del(17p) 10 pts, del(11q) 9 pts). No grade (G) 3 or 4 infusion reactions, neutropenia, or thrombocytopenia have been observed. The majority of adverse events (AE) were G1/2. G3/4 AE included anemia (11%), pneumonia (11%), UTI (7%), hyponatremia (7%). 24/24 CLL/SLL/PLL pts have achieved PR (100% ORR) within 6 cycles; 2/3 RT pts had PR. With median follow-up of 6.5 mo (range 5.3-10.2 mo), 23 CLL/SLL/PLL pts and 1 RT pt remain on study; 1 CLL/SLL pt went to transplant in PR; 2 RT pts progressed. Conclusions: PCI-32765 combined with ofatumumab is well tolerated and highly active (100% ORR) in pts with heavily pre-treated R/R CLL/SLL. Rapid onset of response, low relapse rate, and favorable safety profile make this combination worthy of further study. Cohorts evaluating other Tx sequences are currently underway.

The absence of detectable fetal microchimerism in nontransgenic goats (Capra aegagrus hircus) bearing transgenic offspring

Regulations for the disposal of genetically engineered animals are strict due to concern for their inappropriate introduction into the food chain, and of the possible public health and environmental impacts of these organisms. Nontransgenic animals that give birth to transgenic offspring are treated as if they are transgenic due to concern of fetal cells crossing the placental barrier and residing in the mother (fetal-maternal microchimerism). Determining whether or not fetal-fetal or fetal-maternal transfer of DNA or cells occurs during caprine gestation is critical to effectively protect the public without culling animals that pose no risk. Additionally, fetal-maternal transfer, should it exist in the goat, could contraindicate the rebreeding of nontransgenic dams due to the possible transfer of fetal cells from 1 pregnancy to the fetus of subsequent pregnancies. Fetal-maternal transfer in Capra hircus has not been reported in the literature, although it has been reported in another ruminant, Bos taurus. We examined blood from nontransgenic dams that carried transgenic offspring using a PCR method sensitive enough to detect the presence of a spider silk transgene to a 1:100,000 dilution. At this sensitivity, we did not detect the occurrence of fetal-maternal transfer in 5 nontransgenic dams. Likewise, fetal-fetal transfer was not observed from a transgenic to a nontransgenic twin in utero. To test tissue-specific expression of the silk transgene, proteins purified from standard necropsy tissue from a lactating transgenic dam were examined by Western blot analysis. Silk protein expression was only observed in mammary tissue consistent with the tissue specificity of the β-casein promoter used in the transgenic construct. We report evidence collected from a limited caprine breeding pool against transfer of transgenes in utero from fetus to dam and fetus to fetus. In addition, we show evidence that the β-casein promoter in our expression construct is not expressed ectopically as previously suggested. These results suggest that transgene transfer in utero does not occur, but further study is warranted with a larger sample group to confirm these results.

Risk factors for tumor lysis syndrome in patients with chronic lymphocytic leukemia treated with the cyclin-dependent kinase inhibitor, flavopiridol

Tumor lysis syndrome (TLS) has been described in over 40% of patients with chronic lymphocytic leukemia treated with the cyclin-dependent kinase inhibitor, flavopiridol. We conducted a retrospective analysis to determine predictive factors for TLS. In 116 patients, the incidence of TLS was 46% (95% CI: 36-55%). In univariable analysis, female gender, greater number of prior therapies, Rai stages III-IV, adenopathy ≥ 10 cm, splenomegaly, del(11q), decreased albumin and increased absolute lymphocyte count, white blood cell count (WBC), β2-microglobulin, and lactate dehydrogenase were associated (P < 0.05) with TLS. In multivariable analysis, female gender, adenopathy ≥ 10 cm, elevated WBC, increased β2-microglobulin, and decreased albumin were associated with TLS (P < 0.05). With respect to patient outcomes, 49 and 44% of patients with and without TLS, respectively, responded to flavopiridol (P = 0.71). In a multivariable analysis, controlling for number of prior therapies, cytogenetics, Rai stage, age and gender, progression-free survival (PFS) was inferior in patients with TLS (P = 0.01). Female patients and patients with elevated β2-microglobulin, increased WBC, adenopathy ≥ 10 cm and decreased albumin were at highest risk and should be monitored for TLS with flavopiridol. TLS does not appear to be predictive of response or improved PFS in patients receiving flavopiridol.

Diagnostic ultrasound at MACH 20: retroperitoneal and pelvic imaging in space

An operationally available diagnostic imaging capability augments spaceflight medical support by facilitating the diagnosis, monitoring and treatment of medical or surgical conditions, by improving medical outcomes and, thereby, by lowering medical mission impacts and the probability of crew evacuation due to medical causes. Microgravity-related physiological changes occurring during spaceflight can affect the genitourinary system and potentially cause conditions such as urinary retention or nephrolithiasis for which ultrasonography (U/S) would be a useful diagnostic tool. This study describes the first genitourinary ultrasound examination conducted in space, and evaluates image quality, frame rate, resolution requirements, real-time remote guidance of nonphysician crew medical officers and evaluation of on-orbit tools that can augment image acquisition. A nonphysician crew medical officer (CMO) astronaut, with minimal training in U/S, performed a self-examination of the genitourinary system onboard the International Space Station, using a Philips/ATL Model HDI-5000 ultrasound imaging unit located in the International Space Station Human Research Facility. The CMO was remotely guided by voice commands from experienced, earth-based sonographers stationed in Mission Control Center in Houston. The crewmember, with guidance, was able to acquire all of the target images. Real-time and still U/S images received at Mission Control Center in Houston were of sufficient quality for the images to be diagnostic for multiple potential genitourinary applications. Microgravity-based ultrasound imaging can provide diagnostic quality images of the retroperitoneum and pelvis, offering improved diagnosis and treatment for onboard medical contingencies. Successful completion of complex sonographic examinations can be obtained even with minimally trained nonphysician ultrasound operators, with the assistance of ground-based real-time guidance.

The impact of immigration on tuberculosis rates in the United Kingdom compared with other European countries

OBJECTIVE

To investigate whether trends in tuberculosis (TB) rates across Europe are linked to patterns of migration.

DESIGN

Descriptive analysis of Organisation for Economic Co-operation and Development population statistics and EuroTB data for 21 European countries for 1996-2005.

RESULTS

TB notification rates increased in only three of the 21 countries: the United Kingdom, Norway and Sweden. In all three countries, approximately three quarters of cases were foreign-born. The UK had the third highest number of foreign nationals overall, but the highest number from a country with a TB incidence > or =250 cases/100000 (219000, 13%). European countries with declining TB rates had varying patterns of migration, but did not generally receive migrants from very high-incidence countries and/or had a smaller proportion of their total TB cases in their migrant population.

CONCLUSIONS

The increase in the rate of TB in the UK, which contrasts with most other European countries, may, at least in part, be due to the fact that a high proportion of UK cases occur in the foreign-born, coupled with a comparatively large number of foreign nationals from countries with a very high incidence of TB.

Salivary lysozyme and prevalent hypertension

Although the etiology of essential hypertension is not clearly understood, endothelial dysfunction from chronic infection and/or impaired glucose metabolism may be involved. We hypothesized that salivary lysozyme, a marker for oral infection and hyperglycemia, might display a significant relationship with hypertension, an early stage of cardiovascular disease. Logistic regression analyses of the Kuopio Oral Health and Heart Study demonstrated that persons with higher lysozyme levels were more likely to have hypertension, after adjustment for age, gender, smoking, BMI, diabetes, the ratio of total cholesterol to HDL cholesterol, and C-reactive protein. The exposure to increasing quartiles of lysozyme was associated with adjusted Odds Ratios for the outcome, hypertension, 1.00 (referent), 1.25, 1.42, and 2.56 (linear trend p < 0.003). When we restricted the sample to the individuals without heart disease (N = 250), we observed a non-significant trend for increasing odds. Our hypothesis--"high salivary lysozyme levels are associated with the odds of hypertension"--was confirmed.

New developments to support decision-making in contaminated inhabited areas following incidents involving a release of radioactivity to the environment

The Chernobyl accident demonstrated that releases from nuclear installations can lead to significant contamination of large inhabited areas. A new generic European decision support handbook has been produced on the basis of lessons learned on the management of contaminated inhabited areas. The handbook comprises detailed descriptions of 59 countermeasures in a standardised datasheet format, which facilitates a comparison of features. It also contains guidance in the form of decision flowcharts, tables, check lists and text to support identification of optimised solutions for managing the recovery of inhabited areas within a framework consistent with ICRP recommendations. A new comprehensive inhabited-area dose model is also being developed for implementation in the ARGOS and RODOS decision support systems. Shortcomings of previous models are demonstrated. Decision support modelling in relation to malicious dispersion of radioactive matter in inhabited areas is also discussed. Here, the implications of, e.g., particle sizes and dispersion altitude are highlighted.

Musculoskeletal morbidity: the growing burden of shoulder pain and disability and poor quality of life in diabetic outpatients

OBJECTIVE

To investigate shoulder pain and disability and quality of life (QoL) over 12 months in patients with diabetes and in a non-diabetic control group.

METHODS

Cross-sectional study with 12-month follow-up in diabetic (n=189) and medical (n=99) outpatients employing the Shoulder Pain and Disability Index (SPADI) and SF-36 version 2. The results were analysed using restricted maximum likelihood (REML).

RESULTS

The prevalence of current shoulder symptoms was 35% in diabetics and 17% in controls. Shoulder pain and disability as calculated by the SPADI were independently associated with diabetes (vs controls) and current shoulder symptoms, and worsened over 12 months. Disability scores worsened with age in diabetics, and pain scores were higher in diabetics than controls among patients reporting current shoulder symptoms. Poor physical QoL worsened over time in patients with diabetes and was worse in patients with current shoulder symptoms, whether they had diabetes or not. Mental QoL was worse only in patients with current shoulder symptoms.

CONCLUSION

Shoulder symptoms are common, affecting 1 in every 3 diabetic patients and 1 in every 6 control patients. In this study shoulder pain, disability and physical QoL were poorer among diabetics and patients reporting current shoulder symptoms, and worsened over time. Mental QoL was worse in patients reporting current shoulder symptoms and was independent of diabetes. Therefore, shoulder symptoms are common, are associated with poor physical and mental QoL in addition to shoulder pain and disability, and are worse in patients with diabetes, even in a population with relatively moderate shoulder pain and disability.

Mechanisms of action for an anti-radiation vaccine in reducing the biological impact of high dose and dose-rate, low-linear energy transfer radiation exposure

The development of an anti-radiation vaccine could be very useful in reducing acute radiation syndromes. Existing principles for the treatment of acute radiation syndromes are based on the amelioration of progressive pathophysiological changes, using the concept of replacement therapy. Active immunization by small quantities of the essential radiation-induced systemic toxins of what we call the Specific Radiation Determinant (SRD) before irradiation increased duration of life among animals that were irradiated by lethal or sub-lethal doses of gamma-radiation. The SRD toxins possess antigenic properties that are specific to different forms of acute radiation sickness. Intramuscular injection of larger quantities of the SRD toxins induce signs and symptoms in irradiated naive animals similar to those observed in acute radiation syndromes, including death. Providing passive immunization, at variable periods of time following radiation, with preparations of immune-globulins directed at the SRD molecules, can confer some protection in the development of clinical sequelae in irradiated animals. Improved survival rates and times were observed in animals that received lower, sublethal doses of the same SRDs prior to irradiation. Therefore, active immunization can be induced by SRD molecules as a prophylaxis. The protective effects of the immunization begin to manifest 15-35 days after an injection of a biologically active SDR preparation. The SRD molecules are a group of radiation toxins with antigenic properties that correlate specifically with different forms of radiation disease. The SRD molecules are composed of glycoproteins and lipoproteins that accumulate in the lymphatic system of mammals in the first hours after irradiation, and preliminary analysis suggests that they may originate from cellular membrane components. The molecular weight of the SRD group ranges from 200-250 kDa. The SRD molecules were isolated from the lymphatic systems of laboratory animals that were irradiated with doses known to induce the development of cerebral (SRD-1), non-specific toxic effects (SRD-2), gastrointestinal (SRD-3) and hematological (bone marrow) (SRD-4) syndromes. Our results suggest that an anti-radiation vaccine can be developed for prophylactic use against radiation damage induced by acute exposure to significant doses of low Linear Energy Transfer (LET) radiation for humans, including nuclear power workers, commercial and military pilots, cosmonauts/astronauts, nuclear-powered engine vessel operators and possibly even the civilian population in the case of a nuclear terrorism event.

Tuberculosis in non-UK-born persons, England and Wales, 2001-2003

SETTING

England and Wales, 2001-2003.

OBJECTIVES

To describe demographic and clinical characteristics of tuberculosis (TB) in non-UK-born persons and compare with UK-born cases to inform public health action and health service provision.

DESIGN

Analysis of surveillance data.

RESULTS

Among the 67% of cases who were non-UK-born, TB incidence was 88/100000 compared to 4/100000 among the UK-born. UK-born minority ethnic groups were also at increased risk of TB. Although the highest TB incidence occurred in recent entrants to the UK, nearly half the cases had been resident for >or=5 years. The majority of non-UK-born cases originated from South Asia (48%) and sub-Saharan Africa (35%). The demographic characteristics of non-UK-born and UK-born cases differed. In addition, non-UK-born cases were less likely to have pulmonary TB than the UK-born (52% vs. 73%, chi(2) P<0.001), but were more likely to have isoniazid-resistant disease (8% vs. 6%, chi(2) P=0.002), depending on region of birth.

CONCLUSIONS

During 2001-2003, most TB cases were non-UK-born. TB services need to take the characteristics of TB in this group into account. Furthermore, awareness of the risk of disease is required among the non-UK-born for many years after arrival into the UK, and among UK-born minority ethnic groups.

Comparison of DNA extraction methods for analysis of turkey cecal microbiota

AIM

As a prelude to long-term studies to characterize the microbiota of the turkey ceca, 14 DNA isolation protocols were evaluated for their ability to reproducibly characterize microbial diversity.

METHODS AND RESULTS

Eight commercially available DNA extraction kits were assessed. DNA quantity and quality were assessed and competitive PCR was used to quantify the 16S bacterial rRNA genes. The Invitrogen Easy-DNA Kit extraction method for large samples yielded over eight times more DNA than any other method (3144 +/- 873 microg g(-1) of sample, P < 0.05). Bacterial and fungal species richness was estimated by Automated Ribosomal Intergenic Spacer Analysis. The Invitrogen Easy-DNA Kit generated the greatest bacterial species richness (46 +/- 7 peaks) while Bio-Rad Aquapure yielded the highest fungal species richness (71 +/- 9.5 peaks).

CONCLUSION

Cluster analysis indicated different DNA extraction methods generated different microbial community compositions using the same cecal matrix from a single donor bird.

SIGNIFICANCE AND IMPACT OF THE STUDY

Optimized DNA extraction protocols Invitrogen Easy-DNA Kit extraction method for large samples and Bio-Rad Aquapure outperform other methods for extraction of DNA from poultry fecal samples, although these methods do not necessarily recover all available DNA. They will be used in future studies to monitor the dynamics of microbial communities of the avian ceca.

Sphingolipid-binding proteins

Emerging information on sphingolipid metabolism and signaling is leading to a better understanding of cellular processes such as apoptosis, cancer, cell survival and aging. In this review, we discuss the involvement of sphingolipids in these processes and focus on underlying mechanisms based on sphingolipid:protein interactions. Due to the inherent difficulty of studying lipids, we discuss techniques that are useful in the elucidation of these interactions. We classify sphingolipid-binding proteins into four main classes: receptor, effector, enzyme, and transporter. Known structures of sphingolipid-binding proteins are surveyed, and sphingolipid-binding characteristics are described, acknowledging the limitations that there are presently insufficient protein:sphingolipid complexes for more definitive conclusions on this topic. Finally we summarize relevant literature to better inform the reader about sphingolipid:protein interactions.

No increase in human cases of Mycobacterium bovis disease despite resurgence of infections in cattle in the United Kingdom

A resurgence of Mycobacterium bovis infections in cattle in the United Kingdom since the 1980s has raised concern about risks to human health. Enhanced surveillance data for England, Wales and Northern Ireland between 1993 and 2003 of culture-positive human M. bovis cases identified 315 M. bovis infections; the mean annual number of cases was 28 (range 12-41). The most frequently reported exposures were consumption of unpasteurized dairy products 41/83 (49%) and exposure to cattle 45/123 (37%). Of all cases, 249 (83%) were born before 1960. Of 50 cases born after 1960, only 14 were born in the United Kingdom. Over the same time period the annual number of new herd infections increased from 332 to 1749 as derived from the UK State Veterinary Service database. In conclusion, despite a more than fivefold increase in cattle herd infections during the 1990s, there was no increase in reported human cases.

Application of a generic biosphere model for dose assessments to five European sites

The BIOMOSA (BIOsphere MOdels for Safety Assessment of radioactive waste disposal) project was part of the EC fifth framework research programme. The main goal of this project was to improve the scientific basis for the application of biosphere models in the framework of long-term safety studies of radioactive waste disposal facilities and to enhance the confidence in using biosphere models for performance assessments. The study focused on the development and application of a generic biosphere tool BIOGEM (BIOsphere GEneric Model) using the IAEA BIOMASS reference biosphere methodology, and the comparison between BIOGEM and five site-specific biosphere models. The site-specific models and the generic model were applied to five typical locations in Europe, resulting in estimates of the annual effective individual doses to the critical groups and the ranking of the importance of the exposure pathways for each of the sites. Uncertainty in the results was also estimated by means of stochastic calculations based on variation of the site-specific parameter values. This paper describes the generic model and the deterministic and stochastic results obtained when it was applied to the five sites. Details of the site-specific models and the corresponding results are described in two companion papers. This paper also presents a comparison of the results between the generic model and site-specific models. In general, there was an acceptable agreement of the BIOGEM for both the deterministic and stochastic results with the results from the site-specific models.

Does periodontal treatment improve glycemic control in diabetic patients? A meta-analysis of intervention studies

Previous analyses regarding effects of periodontal treatment on glycemic control included studies where causal association might not be assumed, or the results were reported non-quantitatively. We initiated this meta-analysis of 10 intervention studies to quantify the effects of periodontal treatment on HbA1c level among diabetic patients, to explore possible causes for the discrepant reports, and to make recommendations for future studies. Data sources were MEDLINE (January, 1980, to January, 2005), the EBMR, Cochrane Register, and bibliographies of the published articles. Three investigators extracted data regarding intervention, outcomes, and effect size. A total of 456 patients was included in this analysis, with periodontal treatment as predictor and the actual change in hemoglobin A1c level as the outcome. The weighted average decrease in actual HbA1c level was 0.38% for all studies, 0.66% when restricted to type 2 diabetic patients, and 0.71% if antibiotics were given to them. However, none was statistically significant.

The EXPURT model for calculating external gamma doses from deposited material in inhabited areas

EXPURT, NRPB's model for calculating external gamma doses in inhabited areas, was originally developed in the mid-1980s. Deposition on surfaces in the area, the subsequent transfer of material between different surfaces or its removal from the system, and dose rates in various locations from material on the different surfaces are modelled. The model has been updated to take account of more recent experimental data on the transfer rates between surfaces and to make it more flexible for use in assessing dose rates following an accidental release. EXPURT is a compartmental model and models the transfer of material between the surfaces using a set of first order differential equations. It enables the impact of the decontamination of surfaces on doses and dose rates to be explored. The paper describes the EXPURT model and presents some preliminary results obtained using it.

Requirements of future models for inhabited areas

Models for inhabited areas are used in a variety of applications for accidental or continuous releases of radioactivity to atmosphere. Pathways of interest are external exposure from radioactive material in the cloud or deposited on indoor and outdoor surfaces and people, inhalation from the plume and from material resuspended from the ground. In developing a model for inhabited areas it is necessary to consider what the end users may need and ensure that the model is appropriate for the application; different levels of detail may be appropriate for different applications. This paper considers the main processes governing exposure in inhabited areas, commenting on the extent to which we understand them and how well current models reflect this understanding. It also identifies where the authors believe future modelling is needed and the key areas where the current inhabited area models could be improved.

Genitourinary issues during spaceflight: a review

The genitourinary (GU) system is not uncommonly affected during previous spaceflights. GU issues that have been observed during spaceflight include urinary calculi, infections, retention, waste management, and reproductive. In-flight countermeasures for each of these issues are being developed to reduce the likelihood of adverse sequelae, due to GU issues during exploration-class spaceflight, to begin in 2018 with flights back to the Moon and on to Mars, according to the February 2004 Presendent's Vision for US Space Exploration. With implementation of a robust countermeasures program, GU issues should not have a significant threat for mission impact during future spaceflights.

Generation and interrogation of a pure nuclear spin state by parahydrogen-enhanced NMR spectroscopy: a defined initial state for quantum computation

We describe a number of studies used to establish that parahydrogen can be used to prepare a two-spin system in a pure state, which is suitable for implementing NMR quantum computation. States are generated by pulsed and continuous-wave (CW) UV laser initiation of a chemical reaction between Ru(CO)(3)(L(2)) [where L(2) = dppe = 1,2-bis(diphenylphosphino)ethane or L(2) = dpae = 1,2-bis(diphenylarsino)ethane] with pure parahydrogen (generated at 18 K). This process forms Ru(CO)(2)(dppe)(H)(2) and Ru(CO)(2)(dpae)(H)(2) on a sub-microsecond time-scale. With the pulsed laser, the spin state of the hydride nuclei in Ru(CO)(2)(dppe)(H)(2) has a purity of 89.8 +/- 2.6% (from 12 measurements). To achieve comparable results by cooling would require a temperature of 6.6 mK, which is unmanageable in the liquid state, or an impractical magnetic field of 0.44 MT at room temperature. In the case of CW initiation, reduced state purities are observed due to natural signal relaxation even when a spin-lock is used to prevent dephasing. When Ru(CO)(3)(dpae) and pulsed laser excitation are utilized, the corresponding dihydride product spin state purity was determined as 106 +/- 4% of the theoretical maximum. In other words, the state prepared using Ru(CO)(3)(dpae) as the precursor is indistinguishable from a pure state.

Preparing high purity initial states for nuclear magnetic resonance quantum computing

Here we demonstrate how parahydrogen can be used to prepare a two-spin system in an almost pure state which is suitable for implementing nuclear magnetic resonance quantum computation. A 12 ns laser pulse is used to initiate a chemical reaction involving pure parahydrogen (the nuclear spin singlet of H2). The product, formed on the micros time scale, contains a hydrogen-derived two-spin system with an effective spin-state purity of 0.916. To achieve a comparable result by direct cooling would require an unmanageable (in the liquid state) temperature of 6.4 mK or an impractical magnetic field of 0.45 MT at room temperature. The resulting spin state has an entanglement of formation of 0.822 and cannot be described by local hidden variable models.

Rural GPs' ratings of initiatives designed to improve rural medical workforce recruitment and retention

INTRODUCTION

Since the early 1990s, Australian governments have recognised the problems of rural medical workforce recruitment and retention and have implemented a range of programs and incentives designed to improve the supply of, and access to, doctors in rural and remote areas. Some incentives involve differential payments according to degree of rurality or remoteness. Since these programs involve considerable costs to governments, some assessment of their impact on recruitment or retention is warranted. The objective of this study is to examine the effectiveness of different recruitment and retention incentives from the perspective of the rural GP. Doctors practising in rural and remote communities were, therefore, asked to rank the relative importance of different interventions in terms of their impact on recruitment to and retention of GPs in their communities.

METHODS

Six possible interventions were selected to cover the major objectives underpinning rural workforce programs most relevant to doctors currently in rural practice. Respondents assigned a rank to indicate the relative importance of each item with respect to each of the two questions: "What would help most to attract more GPs to this community?" and "What would help most to retain GPs in this community?" The data were collected as part of a national study into the viability of rural general practice undertaken jointly by the Rural Doctors Association of Australia and Monash University School of Rural Health Bendigo. The Rural, Remote and Metropolitan Areas (RRMA) classification was used as the rurality indicator. Analysis involved the calculation of mean ranks for each item. Item means were then ranked to indicate most to least important items in total, and within each RRMA category.

RESULTS

Thirty-five percent of all GPs practising in rural and remote Australia responded to the national survey, representing 53% of all practices in those areas. Of these, 1050 doctors who nominated themselves as a principal, partner or associate in their practice were eligible for inclusion in this analysis. The results showed a high degree of agreement in the responses to both questions, with the possible interventions being ranked in the same overall order. 'Better remuneration for Medicare consultations' and 'Improved after-hours and on-call arrangements' were ranked as the most important interventions for both attracting and retaining GPs, whereas 'Better education and professional support activity' and 'Improved availability of allied health professional services' were ranked as least important of the options presented. 'Better locum availability' and 'Capital funding to improve practice infrastructure/enable GPs to set up practice' ranked in between. Results within each RRMA category were very similar to the overall rankings, confirming the significance of the improved remuneration and workload arrangements, regardless of geographical location.

CONCLUSIONS

Ensuring professional support, workforce supply, income and infrastructure support are all relevant to the recruitment and retention of GPs in rural and remote areas. However, from the perspective of GPs practising in such areas, specific initiatives that increase the core income of rural practices, and which address those medical workforce supply issues which impact most on workload, are considered those which are most likely to assist in the recruitment and retention of GPs to Australia's rural and remote communities.