Edentulism Predicts Cognitive Decline in the US Health and Retirement Cohort Study

This longitudinal cohort study examines if 1) cognitive decline varies by birth cohort, adjusting for covariates, and 2) edentulism and nonuse of dental care predict 10-y cognitive decline (2008-2018). The Health and Retirement Study (HRS) features a representative sample of US adults over age 50. Eligibility criteria included having cognitive interview data available and responding to the question, "Have you lost all of your upper and lower natural permanent teeth?" at 2+ time points between 2006 and 2018. Use of dental care in the past 2 y was assessed. Linear mixed models for repeated measures estimated the trajectories of mean cognition over time for the birth cohorts, adjusted for baseline cognition, dentition status, dental care use, and covariates (demographic characteristics, health behaviors, and medical conditions). Cohort-by-time interaction terms were included to assess if cognitive decline varied by birth cohort. Ten-year change in cognition status (measured by HRS Cogtot27)-categorized as dementia (<7); cognitive impairment, not demented (7-11) 7≤Cogtot27<12; and normal (≥12)-was also investigated according to birth cohort, dentition status, and dental care use. Mean (SD) baseline age was 63.4 (10.1) y (n = 22,728). Older birth cohorts had greater cognitive decline than younger cohorts. Linear mixed-model estimates and 95% confidence intervals for protective factors for cognitive decline included higher baseline cognition (HRS Cogtot27) (0.49; 0.48-0.50), use of dental care in the past 2 y (0.17; 0.10-0.23), and covariates such as greater household wealth and being married. Risk increased with being edentulous (-0.42; -0.56 to -0.28), history of stroke or diabetes, less education, Medicaid recipient, current smoker, loneliness, and poor/fair self-rated health. Edentulism and irregular dental care are among important predictors of cognitive decline. Tooth retention and regular dental care throughout life appear to be important for maintaining oral and cognitive health.

Topical Fluoride Effectiveness in High Caries Risk Adults

This retrospective analysis of longitudinal data was developed to determine which types, combinations, and intensities of topical fluorides more effectively prevent new caries-related restorations and extractions in high caries risk adults. We included data from October 1, 2008, through June 30, 2018, from electronic dental and medical records and pharmacy database from the US Department of Veterans Affairs. Veterans who were eligible for continuing and comprehensive care, met the criteria of high caries risk (received 2 or more caries-related restorations within a 365-d period), and had 3 y of follow-up were included. Multivariable logistic regression models estimated the odds of caries-related treatment during the 1-y observation period, controlling for age, gender, race and ethnicity, illness burden (Selim comorbidity index), use of prescription medications, attendance at dental prophylaxis appointments, number of caries-related restorations during the index year, and time between first and last caries-related restoration during the index year. The study sample included 68,757 veterans, who were primarily male (91.5%), were White (73.6%), had a mean age of 59.2 ± 13.5 y, and had significant medical comorbidity as measured by the Selim index (3.7 ± 2.4 physical and 1.3 ± 1.2 mental diagnoses). They had 10.8 ± 6.3 prescription VA drug classes, took 0.6 ± 0.8 strong anticholinergic medications, and had 3.9 ± 2.6 teeth restored due to caries during the index year. Adjusted multivariable logistic regression models showed veterans who received a varnish or gel/rinse fluoride intervention versus no fluoride had an approximately 29% decreased odds of receiving caries-related treatment during the observation period (gel/rinse adjusted odds ratio [AOR] = 0.72; 95% confidence interval [CI], 0.67-0.76; varnish AOR = 0.71; 95% CI, 0.67-0.75). The receipt of a varnish and gel/rinse did not demonstrate statistically better odds than each intervention alone (AOR = 0.69; 95% CI, 0.64-0.75). A dose-response effect was observed. Two-plus applications of varnish versus none (AOR = 0.73; 95% CI, 0.69-0.77) and 2-plus applications of gel/rinse versus none (AOR = 0.71; 95% CI, 0.67-0.75) were more effective than 1 application of either modality versus none.

Abnormal lymphatic phenotype in a CRISPR mouse model of the human lymphedema-causing Connexin47 R260C point mutation

Connexin proteins form gap junctions controlling exchange of ions and small molecules between cells and play an important role in movement of lymph within lymphatic vessels. Connexin47 (CX47) is highly expressed in lymphatic endothelial cells and CX47 missense mutations, i.e., R260C, cosegregate with primary lymphedema in humans. However, studies utilizing CX47 knockout mice have failed to demonstrate any lymphatic anomalies. To unravel the lymphatic consequences of expressing a mutant CX47 protein, we used CRISPR technology to create a mouse carrying a Cx47 missense mutation (Cx47R259C) equivalent to the human CX47R260C missense mutation associated with human primary lymphedema. Intradermal Evans Blue dye injection identified a 2-fold increase in regional lymph nodes in homozygous Cx47R259C mice compared to wildtype, particularly in the jugular region (4.8 ± 0.4 and 2.0 ± 0.0, respectively, p<0.01). Associated lymphatic channels were increased in Cx47R259C mice and mesenteric lymph reflux occurred in homozygous Cx47R259C mice but not in wildtype. Contractility of superficial cervical lymphatics, assessed by pressure myography, was reduced in homozygous Cx47R259C mice compared to wildtype. In conclusion, our data are the first to demonstrate a role for the Cx47 protein in lymphatic anatomy and function. This phenotype is similar to that found with other valve deficient mouse mutants, e.g., in Foxc2. Of significance, this study is the first to use CRISPR technology to develop a pre-clinical model of primary lymphedema and demonstrates the importance of distinguishing between lack of and presence of mutant protein when developing clinically relevant animal models for translation of pre-clinical findings.

Drive-noise tolerant optical switching inspired by composite pulses

Electro-optic modulators within Mach-Zehnder interferometers are a common construction for optical switches in integrated photonics. A challenge faced when operating at high switching speeds is that noise from the electronic drive signals will effect switching performance. Inspired by the Mach-Zehnder lattice switching devices of Van Campenhout et al. [Opt. Express17(26), 23793 (2009).] and techniques from the field of Nuclear Magnetic Resonance known as composite pulses, we present switches which offer protection against drive-noise in both the on and off state of the switch for both the phase and intensity information encoded in the switched optical mode.

Long-term efficacy and safety with ibrutinib (ibr) in previously treated chronic lymphocytic leukemia (CLL): Up to four years follow-up of the RESONATE study

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Background: Ibr, a first-in-class, once-daily inhibitor of Bruton’s tyrosine kinase, is FDA-approved for all pts with CLL/SLL. We report updated safety and efficacy results with up to 4 y follow-up from the ph III RESONATE trial of ibr vs ofatumumab (ofa). Methods: Pts had ≥1 prior therapy. Pts received 420 mg ibr PO until PD or ofa up to 24 wks. At interim analysis (median 9 mo follow-up), the DMC declared superiority of ibr vs ofa for PFS and OS, and ibr access was recommended for all ofa pts. Long-term follow-up efficacy endpoints are per investigator assessment. Ofa pts were censored at crossover for OS. Results: 391 pts were randomized to receive ibr (n = 195) or ofa (n = 196). Median age was 67 y (40% ≥70 y); 57% had Rai stage III/IV. With median follow-up of 44 mo (53 mo max) for ibr arm, PFS was significantly longer for ibr vs ofa (median NR vs 8 mo, [HR 0.133; P< 0.0001]; 3-y PFS 59% vs 3%) with significant benefit across subgroups. PFS with ibr for del11q subgroup trended to have the most favorable outcome; however, PFS was not statistically different for pts with del17p or del11q or without these FISH abnormalities. At analysis, with the majority of pts (68%) randomized to ofa crossing over to ibr, OS was longer for ibr vs ofa (median OS NR for either arm). The OS rate for ibr at 3 y was 74%. ORR for ibr was 91% with CR/CRi rates (now 9%) increasing over time. Baseline cytopenias improved with extended ibr therapy for hemoglobin (85%), platelet (95%), and absolute neutrophil counts (95%). AE profile of ibr was consistent with previous reports. Major hemorrhage, Gr ≥3 atrial fibrillation, and Gr ≥3 hypertension occurred in 6%, 6%, and 8% of pts, respectively, over a follow-up of up to 4 y. Incidence of most Gr ≥3 AEs decreased from y 1 vs y 2-3: neutropenia- 18% vs 8%; pneumonia- 11% vs 4%; atrial fibrillation- 4% vs 2%, respectively. Discontinuations were most frequently PD (27%) and AE (12%). At analysis, 90 ibr pts (46%) continue ibr on study. Conclusions: Long-term treatment with ibr in this international ph III RESONATE study is tolerable and continues to show sustained PFS and OS regardless of high-risk cytogenetics. Ph III results in relapsed del17p and del11q pts compare favorably to prior ph II reports. Clinical trial information: NCT01578707.

Association of FDG PET-CT (PET) avid skeletal lesions (SL) with progression-free survival (PFS) in patients (pts) with previously untreated follicular lymphoma (FL)

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Background: PET scan is frequently utilized in FL. Reduced EFS has been observed in DLBCL pts with SL treated with RCHOP (Held, JCO 31:4115, 2013). Methods: We performed a retrospective single center study to assess outcomes of FL pts with PET avid SL between January 2005 and November 2015. 131 pts with newly diagnosed FL and PET performed within 1 month of diagnosis were included. Results: 32 of these pts had SL (median 4, range 1-11) on initial PET. Median age was 57 (range 43-79), 15 (47%) were female, 30 (94%) had stage IV disease, LDH was elevated in 6 (19%), 6 (19%) had bulky disease > 6 cm, and FLIPI-1 score was low in 5, intermediate in 11, and high 16 pts. 27 pts had grade (gr) 1-2 FL, 2 had gr 3a, and 3 had gr 3 (not classified). All but 1 patient received rituximab (R)-containing therapy (9 received BR, 7 received RCHOP, 5 RCVP, 9 other). 8 pts received maintenance R, and none received radiation. There were no statistically significant differences in median age, tumor gr, LDH, or use of anthracycline containing therapy (28% in SL group vs 16% in non-SL group, p = 0.13) in pts with SL compared to those without SL (n = 99). Pts with SL had higher incidence of bone marrow involvement (27% vs 9%, p = 0.013). With a median follow-up of 35 months, SL pts had 44% rate of transformation to DLBCL compared 12% in non-SL pts (p = 0.004). Median PFS was 45.8 months in SL pts not-reached in non-SL pts (p = 0.003). Median OS was 105.9 months in SL pts and not reached in non-SL pts (p = 0.08). In the multi-variate analysis, SL (p = 0.037), male gender (p = 0.048), higher FLIPI-1 score (p = 0.009), and absence of anthracycline containing therapy (p = 0.005) were significantly associated with decreased PFS using backward selection. Conclusions: The presence of PET identified SL in previously untreated FL is associated with an increased risk of transformation and reduced PFS in this single center retrospective analysis. Larger studies of uniformly treated pts are needed to validate these data. The identification of high-risk PET avid SL in FL pts in future prospective therapeutic trials could be used to select pts for specific induction regimens, maintenance rituximab, or consolidative radiation.

Optimizing Metabolic Pathways for the Improved Production of Natural Products

Metabolic engineering strives to develop microbial strains that are capable of high-titer production of a variety of industrially significant pharmaceuticals, nutraceuticals, commodity, and high-value compounds. Despite extensive success with many proof-of-concept systems there is still the need for optimization to achieve industrially relevant titers, yields, and productivities. The field of metabolic pathway optimization and balancing has formed to address this need using a scientific and systematic approach. In this chapter, we aim to outline various pathway optimization and system balancing strategies while giving insights and tips into the systems and procedures that have demonstrated recent success in the peer-reviewed literature.

Sensorimotor learning in children and adults: Exposure to frequency-altered auditory feedback during speech production

Auditory feedback plays an important role in the acquisition of fluent speech; however, this role may change once speech is acquired and individuals no longer experience persistent developmental changes to the brain and vocal tract. For this reason, we investigated whether the role of auditory feedback in sensorimotor learning differs across children and adult speakers. Participants produced vocalizations while they heard their vocal pitch predictably or unpredictably shifted downward one semitone. The participants' vocal pitches were measured at the beginning of each vocalization, before auditory feedback was available, to assess the extent to which the deviant auditory feedback modified subsequent speech motor commands. Sensorimotor learning was observed in both children and adults, with participants' initial vocal pitch increasing following trials where they were exposed to predictable, but not unpredictable, frequency-altered feedback. Participants' vocal pitch was also measured across each vocalization, to index the extent to which the deviant auditory feedback was used to modify ongoing vocalizations. While both children and adults were found to increase their vocal pitch following predictable and unpredictable changes to their auditory feedback, adults produced larger compensatory responses. The results of the current study demonstrate that both children and adults rapidly integrate information derived from their auditory feedback to modify subsequent speech motor commands. However, these results also demonstrate that children and adults differ in their ability to use auditory feedback to generate compensatory vocal responses during ongoing vocalization. Since vocal variability also differed across the children and adult groups, these results also suggest that compensatory vocal responses to frequency-altered feedback manipulations initiated at vocalization onset may be modulated by vocal variability.

Obinutuzumab for the treatment of chronic lymphocytic leukemia

Obinutuzumab is a novel therapeutic anti-CD20 monoclonal antibody recently approved by the United States Food and Drug Administration (FDA) for use in combination with chlorambucil as first-line treatment of chronic lymphocytic leukemia (CLL). It is distinguished from other anti-B-lymphocyte antigen CD20 (anti-CD20) therapeutic antibodies in current clinical use by its type II properties and glycoengineered Fc region. In vitro these unique properties translate into higher rates of antibody-dependent cytotoxicity and direct cell death compared to rituximab, and obinutuzumab demonstrates improved efficacy in human lymphoma xenograft models and whole blood lymphocyte depletion assays. FDA approval was based upon results from a randomized phase III trial comparing treatment with single-agent chlorambucil to the combination of chlorambucil and either rituximab or obinutuzu-mab. The obinutuzumab arm resulted in higher rates of complete remission and significant improvements in progression-free survival versus either comparator regimen. The majority of patients in the obinutuzumab and chlorambucil arm finished all six planned treatment cycles, and therapy was well tolerated. Toxicities of obinutuzumab are similar to those of other anti-CD20 antibodies, although infusion-related reactions and neutropenia appear to be more common. This trial establishes chemoimmunotherapy with obinutuzumab and chlorambucil as an attractive treatment option for CLL patients, particularly those with comorbid medical illnesses or advanced age. Obinutuzumab remains under study in combination with both chemotherapy and novel agents for CLL and non-Hodgkin's lymphoma, where it is expected to find additional clinical applications.

Results of a phase I trial of the proteasome inhibitor carfilzomib in patients with relapsed or refractory chronic lymphocytic leukemia (CLL) and small lymphocytic leukemia (SLL)

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Background: CLL is an incurable malignancy, and survival for patients (pts) with relapsed disease is limited. Carfilzomib (CFZ) has shown efficacy in multiple myeloma, and our group has shown significant in vitro activity in primary CLL cells. Therefore, we have undertaken a phase I trial of this agent in CLL. Methods: This is a single institution phase I trial of CFZ in pts with relapsed or refractory CLL. Primary endpoints were to determine maximal tolerated dose (MTD) and describe toxicity. Pts with CLL relapsed after at least one therapy were enrolled using a 3x3 design. CFZ was administered on the standard myeloma schedule. The first two doses were administered at 20 mg/m2 with remainder given at doses starting at 27 mg/m2 for dose level 1 with escalation to 56 mg/m2. Results: 17 pts received at least 1 dose of CFZ. 12 pts completed at least 1 cycle of therapy, with the remaining 5 experiencing PD during cycle 1. The MTD was not reached, with 3 pts accrued to each dose level to the maximal dose tested without dose limiting toxicity. Most adverse events (AE) were grade (G) 1 or 2. G3/4 AE were quickly reversible and included G3 neutropenia (4 pts), G4 neutropenia (2), G3 febrile neutropenia (1), and G3 thrombocytopenia (3). G1/2 toxicities observed in ≥ 20% of pts included anemia (10), thrombocytopenia (7), and hypocalcemia (8). Median number of cycles was 3, with 9 pts achieving stable disease after 2 cycles. Of 3 pts enrolled at maximal dose level, 2 remain on therapy after 5 and 7 months, with 1 achieving a clinical partial response. Of 5 evaluable pts, at least 50% proteasome inhibition was seen in all at 1 hour, with minimal recovery at 24 hours. PK was best characterized by a two-compartment model. Maximum plasma concentrations across all dose levels ranged from 0.81 to 8.1 uM. Across the evaluated dose range, area under the curve increased in an apparent dose-proportional manner. Conclusions: Despite relatively limited efficacy in this study, CFZ has acceptable toxicity in CLL, with no MTD identified up to 56 mg/m2. This suggests that CFZ may be better studied in CLL using a different schedule or in combination with other active agents. Clinical trial information: NCT01212380.

A phase III, randomized, controlled study evaluating the efficacy and safety of idelalisib (GS-1101) in combination with ofatumumab for previously treated chronic lymphocytic leukemia (CLL)

TPS7131

Background: PI3K-delta is critical for activation, proliferation and survival of B cells and plays a role in homing and retention in lymphoid tissues. PI3Kδ signaling is hyperactive in many B-cell malignancies. Idelalisib is a first-in-class, selective, oral inhibitor of PI3Kδ that reduces proliferation, enhances apoptosis, and inhibits homing and retention of malignant B cells in lymphoid tissues (Lannutti et al, 2011). Ofatumumab (O) is an anti-CD20 monoclonal antibody approved for the treatment of pts with CLL refractory to fludarabine and alemtuzumab. Phase 1 studies demonstrated that idelalisib, as monotherapy or combined with O, is highly active in pts with heavily pretreated CLL: pts experienced profound and rapid regression of lymphadenopathy, reductions in disease-associated chemokines, and durable clinical benefit with an acceptable safety profile (Furman et al, 2012). Methods: This study will enroll 210 pts with CLL previously treated with a purine analog and/or bendamustine, with measurable lymphadenopathy who require treatment for CLL and have disease that is not refractory to ofatumumab, and are expected to benefit from a change in therapy because of CLL progression <24 months since completion of their last prior treatment. Pts are randomized in a 2:1 ratio (Arm A:Arm B). In Arm A, pts receive idelalisib at 150 mg BID continuously in combination with 12 infusions of O at 1000 mg over ~24 weeks (weekly x 8 then monthly x 4). In Arm B, pts receive 12 infusions of O at 2,000 mg over ~24 weeks. Stratification factors address IGHV mutational status, del(17p)/p53 mutation status, and refractory vs relapsed disease. The primary study endpoint is PFS. Secondary endpoints include ORR, lymph node response rate, CR rate, and OS. This is an event-driven trial and primary endpoint evaluation will be based on independent central review. For the primary efficacy analysis, the difference in PFS between the treatment arms will be assessed in the ITT analysis set using Kaplan-Meier methods and the stratified log-rank test. The study opened for enrollment in Dec 2012. Clinical trial information: NCT01659021.

Association of pre-transplantation positron emission tomography/computed tomography and outcome in mantle cell lymphoma

Positron emission tomography/computed tomography (PET/CT)-positive findings before autologous SCT (auto-SCT) are associated with inferior PFS and OS in patients with relapsed Hodgkin's and diffuse large B-cell lymphoma. We classified pre-transplant PET/CT performed before auto-SCT as positive or negative to evaluate the impact of pre-transplant PET/CT in mantle cell lymphoma (MCL). In 29 patients, 17 were PET/CT(-) and 12 were PET/CT(+). PET/CT(+) patients were younger (P=0.04), had lower MCL International Prognostic Index (MIPI, P=0.04) scores, but increased bulky adenopathy >5 cm (45% vs 13%, P=0.09). With a median follow-up of 27 months (range: 5-55 months), 7 patients relapsed (4 in the PET/CT(-) group and 3 in the PET/CT(+) group) with 2 deaths in the PET/CT(+) group without a documented relapse. The estimated 2-year PFS was 64% (95% confidence interval (CI): 0.30-0.85) vs 87% (95% CI: 0.57-0.97) in PET/CT(+) and PET/CT(-) patients, respectively (P=0.054). OS was significantly decreased in PET/CT(+) patients (P=0.007), with 2-year estimates of 60% (95% CI: 0.23-0.84) vs 100% in PET/CT(-) patients. A positive pre-transplant PET/CT is associated with a poor prognosis in patients with MCL. Additional factors may impact the prognostic value of PET/CT, as several PET/CT(+) patients remain in remission.

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.