Programs and interventions promoting health equity in LGBTQ2+ populations in Canada through action on social determinants of health

Sexual and gender minorities (SGM) experience a number of health inequities. That social determinants of health drive these inequities is well-documented, but there is little evidence on the number and types of interventions across Canada that address these determinants for these populations. We conducted an environmental scan of programs in Canada that target SGM, and classified the programs based on their level of intervention (individual/interpersonal, institutional and structural). We found that few programs target women, mid-life adults, Indigenous people or ethnoracial minorities, recent immigrants and refugees, and minority language speakers, and few interventions operate at a structural level.

Future Tail Tales: A Forward-Looking, Integrative Perspective on Tail Research

Synopsis Tails are a defining characteristic of chordates and show enormous diversity in function and shape. Although chordate tails share a common evolutionary and genetic-developmental origin, tails are extremely versatile in morphology and function. For example, tails can be short or long, thin or thick, and feathered or spiked, and they can be used for propulsion, communication, or balancing, and they mediate in predator-prey outcomes. Depending on the species of animal the tail is attached to, it can have extraordinarily multi-functional purposes. Despite its morphological diversity and broad functional roles, tails have not received similar scientific attention as, for example, the paired appendages such as legs or fins. This forward-looking review article is a first step toward interdisciplinary scientific synthesis in tail research. We discuss the importance of tail research in relation to five topics: (1) evolution and development, (2) regeneration, (3) functional morphology, (4) sensorimotor control, and (5) computational and physical models. Within each of these areas, we highlight areas of research and combinations of long-standing and new experimental approaches to move the field of tail research forward. To best advance a holistic understanding of tail evolution and function, it is imperative to embrace an interdisciplinary approach, re-integrating traditionally siloed fields around discussions on tail-related research.

Clinical Evaluation of a Novel Preloaded Intraocular Lens Delivery System During Routine Cataract Surgery

Purpose

To evaluate the clinical handleability and acceptability of a novel preloaded intraocular lens (IOL) delivery system for implantation of the TECNIS ZCB00 IOL (Johnson & Johnson Surgical Vision, Inc., Santa Ana, CA, USA) during routine small-incision cataract surgery.

Subjects and Methods

In this prospective, open-label, noncomparative, unilateral or bilateral, multicenter study, adult subjects with unilateral or bilateral cataracts scheduled for IOL implantation were enrolled. Surgeons and surgical technicians completed per-eye day-of-surgery and end-of-surgical-day questionnaires. The primary endpoint of the study was the rate of acceptable overall clinical performance of the preloaded IOL delivery system. Other endpoints included additional responses from the questionnaires, preimplantation incision size, and safety.

Results

The study included 91 eyes that underwent cataract surgery and IOL implantation using the preloaded delivery system and were available for the 1-day postoperative visit. Five surgeons and 14 surgical technicians from four investigational sites participated in the study. The rate of acceptable overall clinical performance was 100% (91/91) of eyes, with most responses (78/91; 85.7%) being the highest possible rating of 5 (very satisfied). Favorable responses by most surgeons and surgical technicians regarding additional endpoints further highlighted the handleability and acceptability of the preloaded delivery system. No ocular adverse events or lens findings (ie, no cases of IOL instability, haptic breakage, IOL marking, or crimping) were reported.

Conclusion

The results of this study demonstrated that this preloaded IOL delivery system was safe and effective during routine small-incision cataract surgery.

Trial Registration

German Clinical Trials Register identifier, DRKS00014757.

Disruption as opportunity: Impacts of an organizational health equity intervention in primary care clinics

BACKGROUND

The health care sector has a significant role to play in fostering equity in the context of widening global social and health inequities. The purpose of this paper is to illustrate the process and impacts of implementing an organizational-level health equity intervention aimed at enhancing capacity to provide equity-oriented health care.

METHODS

The theoretically-informed and evidence-based intervention known as 'EQUIP' included educational components for staff, and the integration of three key dimensions of equity-oriented care: cultural safety, trauma- and violence-informed care, and tailoring to context. The intervention was implemented at four Canadian primary health care clinics committed to serving marginalized populations including people living in poverty, those facing homelessness, and people living with high levels of trauma, including Indigenous peoples, recent immigrants and refugees. A mixed methods design was used to examine the impacts of the intervention on the clinics' organizational processes and priorities, and on staff.

RESULTS

Engagement with the EQUIP intervention prompted increased awareness and confidence related to equity-oriented health care among staff. Importantly, the EQUIP intervention surfaced tensions that mirrored those in the wider community, including those related to racism, the impacts of violence and trauma, and substance use issues. Surfacing these tensions was disruptive but led to focused organizational strategies, for example: working to address structural and interpersonal racism; improving waiting room environments; and changing organizational policies and practices to support harm reduction. The impact of the intervention was enhanced by involving staff from all job categories, developing narratives about the socio-historical context of the communities and populations served, and feeding data back to the clinics about key health issues in the patient population (e.g., levels of depression, trauma symptoms, and chronic pain). However, in line with critiques of complex interventions, EQUIP may not have been maximally disruptive. Organizational characteristics (e.g., funding and leadership) and characteristics of intervention delivery (e.g., timeframe and who delivered the intervention components) shaped the process and impact.

CONCLUSIONS

This analysis suggests that organizations should anticipate and plan for various types of disruptions, while maximizing opportunities for ownership of the intervention by those within the organization. Our findings further suggest that equity-oriented interventions be paced for intense delivery over a relatively short time frame, be evaluated, particularly with data that can be made available on an ongoing basis, and explicitly include a harm reduction lens.

Abstract P3-10-03: Effects of guideline-concordant treatment on ED visits, hospitalizations, and cost in metastatic breast cancer

Purpose: The National Comprehensive Cancer Network (NCCN) developed treatment guidelines that have directed care of patients with cancer for over 20 years. Receipt of treatment according to these guidelines is increasingly recognized as a marker of high quality care. A knowledge gap exists regarding concordance of treatment regimens for metastatic breast cancer with NCCN guidelines, as well as the potential impact of this concordance (or lack thereof) on resource utilization and costs – an issue that assumes significance in the new era of value-based healthcare.

Methods: From 2007-2013, women with de novo (n=988) or recurrent, treated metastatic breast cancer (n=5,651) were evaluated for concordance of first-line systemic therapy with NCCN guidelines within the SEER–Medicare linked database. Types of non-concordant treatments were reviewed and categorized. Outcomes include monthly rates of ED visits, monthly rates of hospital admissions, total overall and Medicare costs, and mortality. Specific (hospitalizations, antineoplastic agents, growth factor) and total costs to Medicare (excluding home health, hospice, skilled nursing facility) were calculated from initiation of treatment until death or available follow-up and examined by concordance status. Part D costs were excluded because costs are shared by Medicare, other payers, and patients. Cox regression was used to evaluate mortality risk. Student's t-tests, generalized linear models, and generalized mixed effects models were utilized to evaluate the relationship between concordance status and outcomes.

Results: We previously reported the prevalence of non-concordant first-line systemic therapy for de novo metastatic breast cancer (19%) and recurrent metastatic breast cancer (18%). The adjusted risk of mortality was comparable by concordance status. In the current analysis, non-concordant treatments were associated with a 9% increased rate of ED visits and a 7% increased rate of hospitalizations (p<.01). Total Medicare cost for patients receiving concordant and non-concordant treatments was $79,372 and $109,471, respectively (p<.001). Significant cost differences were found when comparing patients receiving concordant and non-concordant treatments by antineoplastic agents ($14,256 vs $24,817, p<.001) and growth factor ($1,754 vs $3,414, p<.001). A trend toward lower cost attributed to hospitalizations was observed for patients receiving concordant treatment compared to those receiving non-concordant treatment ($28,113 vs $34,134, p=.06). Overall, hospitalizations, antineoplastic agents, and growth factor accounted for 56% of total Medicare costs. Average monthly Medicare costs were higher for non-concordant patients by $1,761 (p<.01).

Conclusions: While not associated with increased overall mortality, non-concordant treatment is associated with higher health care utilization rates and cost. Increased costs attributed to non-concordant care were largely driven by antineoplastic agents and growth factor use. These findings may have policy implications for payment reform initiative, in particular pathway programs which aim to reduce variability in care and spending on medications.

Citation Format: Rocque GB, Williams CP, Jackson BE, Halilova KL, Adewakun SA, Pisu M, Forero A, Bhatia S. Effects of guideline-concordant treatment on ED visits, hospitalizations, and cost in metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-10-03.

Abstract P2-07-02: Concordance with National comprehensive cancer network (NCCN) metastatic breast cancer guidelines and impact on overall survival

Introduction:Payers are implementing reimbursement restrictions for non-guideline based care. Limited information exists regarding real-world concordance with guidelines for metastatic breast cancer (MBC) treatment. Further, the impact of non-concordance on mortality is unknown. We address these gaps by using the Surveillance, Epidemiology, and End Results (SEER) Program-linked Medicare database to evaluate national concordance with NCCN guidelines and the association between concordance and mortality.

Methods: From 2007 to 2013, women with de novo (n=988) or recurrent metastatic breast cancer (n=5651) were evaluated for concordance of first-line systemic therapy (hormonal therapy, chemotherapy, and Her2-targeted therapy) with NCCN guidelines. Concordance was defined as receipt of single agent or combination treatments listed on NCCN guidelines. Non-concordant treatments were grouped into 5 categories: single-agent HER2-targeted therapy (33%), adjuvant regimens used in the metastatic setting (12%), therapy mismatched with ER/HER2 status (12%), non-approved bevacizumab regimens (10%), and other miscellaneous reasons (33%). Multivariable logistic regression was used to identify predictors of non-concordance. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox regression to compare all-cause mortality associated with non-concordant vs. concordant treatment adjusted for receptor status, comorbidities, age, race, poverty level, entitlement reason, and treatment year.

Results: Mean age at MBC diagnosis was 69y; 77% were white. Median follow-up was 1.2 years. The prevalence of non-concordant first-line systemic therapy was 19% for de novo MBC and 18% for recurrent MBC. Younger age, hormone-receptor negative status, and Her2-positive status were associated with non-concordant treatments for Stage IV and recurrent MBC patients (p<0.001). Higher poverty by census tract was associated with non-concordance in recurrent MBC (p<0.05). The most frequent category of non-concordant treatment in de novo MBC was use of adjuvant regimens in Stage IV MBC (43%) and use of single-agent HER2-targeted therapy (31%) in recurrent MBCs. Adjusted overall survival was similar for patients with de novo MBC receiving concordant and non-concordant treatments (HR 0.88, CI 0.72-1.65). Mortality was modestly increased for patients with recurrent MBC receiving non-concordant care (HR 1.12, CI 1.02-1.22); however, substantial differences were noted by category of non-concordance. Compared to concordant treatment, single-agent HER2-targeted therapy was associated with decreased risk of mortality (HR 0.78, CI 0.68-0.91). Increased mortality was observed for non-approved bevacizumab use (HR 1.79, CI 1.44-2.22) and other miscellaneous regimens (HR 1.42, CI 1.26-1.60). Mortality for therapy mismatched with ER/HER2 status was similar to concordant treatment (HR 1.13, CI 0.88-1.44).

Conclusions: In the first-line setting, treatment inconsistent with NCCN guidelines remains common (18%). Overall mortality was not substantially higher among non-concordant patients. However, mortality risk varied (in both directions) by category of non-concordance. These findings may provide an opportunity for considering refinement of NCCN guidelines.

Citation Format: Rocque GB, Williams CP, Jackson BE, Halilova KI, Pisu M, Andres F, Smita B. Concordance with National comprehensive cancer network (NCCN) metastatic breast cancer guidelines and impact on overall survival [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-07-02.

Abstract P6-11-02: Hospitalizations and costs during Implementation of a lay navigation program for older patients with breast cancer in the deep south

Background: Patient-centered strategies are needed to enhance the value of cancer care particularly at the end of life. Lay navigators (LN) can be trained to provide an extra layer of support for cancer patients from diagnosis through survivorship or end of life. We hypothesized that integrating LNs into the care team would reduce healthcare utilization and cost for patients with cancer, including those with breast cancer.

Methods: A prospective, observational study of Medicare claims data was conducted of beneficiaries ≥ 65 years old diagnosed with cancer after 2008 who received care within the UAB Health System Cancer Community Network (12 cancer centers of varying size located in AL, MS, TN, GA, and FL). The first breast cancer (BC) patient was enrolled in navigation in April 2013, and ∼18% of BC patients were navigated by the end of 2014. For this analysis, we report on the subset of patients with BC. The outcomes of interest were calculated per quarter from 2012-2014: (1) the proportion of patients with at least 1 hospitalization, (2) the proportion of the 492 deceased BC patients with a hospitalization in the last 30 and 14 days of life and (3) the Total costs for Medicare, excluding prescription drug costs. We used general linear models to evaluate changes in both health care utilization and cost over time, adjusting for age, sex, cancer stage, phase of care, and navigation group. Differential effects for navigated and non-navigated groups were tested with a group*time interaction. Healthcare utilization estimates are presented as Incidence Rate Ratios (IRR), and costs for Medicare as parameter estimates (β) in terms of dollar amounts.

Results: 4835 BC patients received care from 2012-2014: 622 received navigation services. 14.2 % of navigated BC patients were stage III/IV, compared to 9.33% of non-navigated patients. The proportion of hospitalizations trended downward from 7.9% in quarter 1 (Q1) 2012 to 5.7% in Q4 of 2014 (IRR 0.965, p =0.14), with similar decreases for navigated and non-navigated patients (IRR= 1.00, p > 0.05). Hospitalization in the last 30 days and last 14 days of life were 49.7% and 29.3%, respectively, with no between groups difference. Costs per beneficiary per quarter decreased overall from $4,161 in Q1 2012 to $3,010 in Q4 2014 (p <0.0001). In adjusted analysis, the navigated patients had an average $577 greater decline per quarter than the non-navigated patients (βNavigated=-$636; βnon-Navigated=-$59; p<0.0001).

Conclusions: Medicare costs declined during implementation of a lay navigation program, with greater reductions for navigated patients than non-navigated BC patients. Overall hospitalizations also declined, yet rates remain high for breast cancer patients at the end of life. Integration of LNs should be considered by health systems aiming to transition to value-based healthcare delivery.

The project described was supported by Grant Number 1C1CMS331023 from the Department of Health and Human Services, Centers for Medicare & Medicaid Services. The contents of this abstract are solely the responsibility of the authors and do not necessarily represent the official views of the U.S. Department of Health and Human Services or any of its agencies.

Citation Format: Rocque GB, Kvale EA, Jackson BE, Kenzik K, Lisovicz N, Demark-Wahnefried W, Meneses KM, Taylor RA, Acemgil A, Chambless C, Li Y, Martin M, Fouad M, Pisu M, Partridge EE. Hospitalizations and costs during Implementation of a lay navigation program for older patients with breast cancer in the deep south. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-11-02.

Safety, tolerability, and efficacy of raltegravir in a diverse cohort of HIV-infected patients: 48-week results from the REALMRK Study

The racial diversity and gender distribution of HIV-infected patients make it essential to confirm the safety and efficacy of raltegravir in these populations. A multicenter, open-label, single-arm observational study was conducted in a diverse cohort of HIV-infected patients (goals: ≥25% women; ≥50% blacks in the United States), enrolling treatment-experienced patients failing or intolerant to current antiretroviral therapy (ART) and treatment-naive patients (limited to ≤20%). All patients received raltegravir 400 mg b.i.d. in a combination antiretroviral regimen for up to 48 weeks. A total of 206 patients received study treatment at 34 sites in the United States, Brazil, Dominican Republic, Jamaica, and South Africa: 97 (47%) were female and 153 (74%) were black [116 (56%) in the United States]. Of these, 185 patients were treatment experienced: 97 (47%) were failing and 88 (43%) were intolerant to current therapy; 21 patients (10%) were treatment naive. Among treatment-intolerant patients, 55 (63%) had HIV-1 RNA<50 copies/ml at baseline. Overall, 15% of patients discontinued: 13% of men, 18% of women, 14% of blacks, and 17% of nonblacks. At week 48, HIV RNA was <50 copies/ml in 60/94 (64%) patients failing prior therapy, 61/80 (76%) patients intolerant to prior therapy, and 16/21 (76%) treatment-naive patients. Response rates were similar for men vs. women and black vs. nonblack patients. Drug-related clinical adverse events were reported by 8% of men, 18% of women, 14% of blacks, and 9% of nonblacks. After 48 weeks of treatment in a diverse cohort of HIV-infected patients, raltegravir was generally safe and well tolerated with potent efficacy regardless of gender or race.

Promoting LGBT health and wellbeing through inclusive policy development

In this paper we argue the importance of including gender and sexually diverse populations in policy development towards a more inclusive form of health promotion. We emphasize the need to address the broad health and wellbeing issues and needs of LGBT people, rather than exclusively using an illness-based focus such as HIV/AIDS. We critically examine the limitations of population health, the social determinants of health (SDOH), and public health goals, in light of the lack of recognition of gender and sexually diverse individuals and communities. By first acknowledging the unique health and social care needs of LGBT people, then employing anti-oppressive, critical and intersectional analyses we offer recommendations for how to make population health perspectives, public health goals, and the design of public health promotion policy more inclusive of gender and sexual diversity. In health promotion research and practice, representation matters. It matters which populations are being targeted for health promotion interventions and for what purposes, and it matters which populations are being overlooked. In Canada, current health promotion policy is informed by population health and social determinants of health (SDOH) perspectives, as demonstrated by Public Health Goals for Canada. With Canada's multicultural makeup comes the challenge of ensuring that diverse populations are equitably and effectively recognized in public health and health promotion policy.

The role of secreted aspartyl proteinases in Candida albicans keratitis

PURPOSE

To evaluate virulence in a murine keratitis model using Candida albicans homozygous mutants deficient in one or more secreted aspartyl proteinases encoded by SAP genes or in transcriptional factors encoded by EFG1 and CPH1 genes.

METHODS

Corneas of BALB/c mice were scarified and topically inoculated with 10(6) colony-forming units of a C. albicans human isolate (SC5314), triple SAP-null mutants (SAP1-3(-/-) and SAP4-6(-/-)), double mutants (SAP4/5(-/-), SAP4/6(-/-), SAP5/6(-/-), and SAP9/10(-/-) and EFG1(-/-)/CPH1(-/-)), single mutants (SAP4(-/-), SAP5(-/-) and SAP6(-/-), EFG1(-/-), and CPH1(-/-)), SAP6 rescuant, or parental controls (CAF2-1 and CAI-4). Animals were evaluated daily for up to 8 days after inoculation.

RESULTS

Wild-type C. albicans induced severe, sustained ulcerative keratitis, and the fungal strains (CAF2-1 and CAI-4) used to generate mutants had similar corneal pathogenicity. SAP1-3(-/-), SAP4/5(-/-), and SAP9/10(-/-) mutants produced moderate keratitis similar to the virulent parental strain. SAP4-6(-/-), SAP4/6(-/-), and SAP5/6(-/-) gave rise to significantly less severe corneal inflammation. The SAP6(-/-) single mutant resulted in mild nonulcerative keratitis that resolved spontaneously within 5 days, and the SAP6 rescuant reestablished moderate disease severity. The EFG1(-/-)/CPH1(-/-) and EFG1(-/-) mutants had reduced corneal virulence, but the CPH1(-/-) strain resulted in persistent keratitis similar to control corneas.

CONCLUSIONS

The EFG1-regulated SAP6 gene of C. albicans encodes a unique secreted aspartyl proteinase that contributes to corneal pathogenicity. The role of SAP6 during corneal infection appears to be associated with the morphogenic transformation of C. albicans yeasts into invasive filamentous forms.

Corneal virulence of Candida albicans strains deficient in Tup1-regulated genes

PURPOSE

To evaluate the role of rbt genes downstream of Tup1p, a transcription factor regulating fungal filamentation, in experimental Candida albicans keratitis.

METHODS

Corneas of BALB/c mice were scarified and topically inoculated with 10(5) or 10(6) colony-forming units (CFU) of a wild-type human isolate of C. albicans (SC5314), a mutant strain with a transposon-induced homozygous disruption of the rbt1 gene (Tn7-rbt1), its control (DAY286), homozygous rbt knockout mutants deficient in rbt1 (BCa7-4) or rbt4 (BCa11-3), or their parental control (CAF2-1). Eyes were scored daily for clinical severity of fungal keratitis and were examined histopathologically.

RESULTS

With a 10(5) CFU inoculum, the CAF2-1 control and its mutant derivatives (BCa7-4 and BCa11-3) produced significantly lower keratitis scores than did the moderately severe keratitis induced by control strains SC5314 and DAY286 and the Tn7-rbt1 mutant (P < 0.05). At a 10(6) CFU inoculum, all strains induced severe disease except for the rbt4-deficient mutant. Fungal keratitis caused by Tn7-rbt1 was as severe as that of control strains (P > 0.2), and the BCa7-4 mutant initially caused severe disease that gradually waned (P < 0.02). However, the BCa11-3 mutant produced moderate disease that was significantly less severe than that induced by control strains (P < 0.04) and resolved within 1 week.

CONCLUSIONS

The rbt4 gene of C. albicans is a potential virulence factor in posttraumatic corneal infection. Genetically regulated hyphal morphogenesis appears to be involved in the initial pathogenesis of experimental keratomycosis.

Candida albicansStrain-Dependent Virulence and Rim13p-Mediated Filamentation in Experimental Keratomycosis

PURPOSE

To compare the virulence of wild-type Candida albicans strains in a murine model of corneal candidiasis and to investigate the role of fungal filamentation in disease progression.

METHODS

Scarified corneas of immunocompetent or cyclophosphamide-treated BALB/c mice were topically inoculated with one of three human isolates of C. albicans, a homozygous mutant of the pH-dependent filamentation gene rim13 or a mutant reference strain control. Mock-inoculated eyes served as negative controls. Corneal disease was categorized daily for 8 days with quantitative fungal culturing of eyes at 6 hours, 1 day, 4 days, and 8 days after infection and histopathologic examination at 1 day and 4 days after infection.

RESULTS

Corneal disease severity differed significantly among wild-type strains (P < or = 0.02). The rim13(-/-) mutant Tn7-rim13 was fully attenuated, whereas the mutant control DAY286 was fully virulent. Pretreatment of mice with cyclophosphamide increased susceptibility to wild-type C. albicans and partially rescued the attenuated phenotype of the genetically deficient rim13(-/-) fungal mutant. All strains replicated with similar kinetics in vitro, and wild-type strains had similar clearance from infected eyes. Histopathologic findings correlated with disease severity.

CONCLUSIONS

Wild-type strains of C. albicans that differ significantly in ocular pathogenicity correlate with the ability of yeast to produce pseudohyphae and hyphae and to invade corneal tissue. Full attenuation of the fungal rim13(-/-) mutant is the first direct demonstration of a hyphal morphogenesis-related gene as a specific virulence factor for C. albicans during corneal infection.

Genetically regulated filamentation contributes to Candida albicans virulence during corneal infection

Candida albicans is a commensal fungus of the normal flora yet causes opportunistic infection following trauma or surgery and during immunosuppression. C. albicans virulence factors include morphogenesis into invasive filaments, adherence to host cells, and secretion of proteases. This study evaluated the role of fungal hyphal extension in experimental C. albicans keratitis using genetically altered yeast strains. Scarified corneas of adult BALB/c mice were topically inoculated with wild-type (SC5314) or 10 transposon-induced mutant strains of C. albicans and monitored for 4 days post inoculation (PI). In vitro growth kinetics and the yeast strains' ability to bud into pseudohyphae or hyphae were also compared. The wild-type human isolate had a high degree of virulence in the murine cornea, and four fungal strains deficient in genes regulating adherence or encoding membrane proteins did not significantly differ from the parental strain (P>0.3). Five yeast strains deficient in genes involved in filamentation resulted in fully or partially attenuated keratomycosis (P<0.0001). The overall growth kinetics of wild-type and mutant strains were similar in rich media (P>0.9), but mutants with deficient morphogenesis had reduced filamentation in vitro. Phenotypic switching from yeasts to filamentous forms facilitates the establishment and progression of experimental corneal disease by C. albicans.

Adaptation of the WHO guideline for residual DNA in parenteral vaccines produced on continuous cell lines to a limit for oral vaccines

Although there is a WHO guidance for a limit on residual DNA for parenterally administered vaccines produced on continuous cell lines, there is no corresponding guidance for oral vaccines. To help determine an oral limit, we performed a study of Vero cell DNA uptake in rats, in which the relative uptake and persistence of Vero cell DNA administered orally was compared to its uptake when delivered intramuscularly (IM). The results of this study allowed the generation of an empirically derived IM versus oral factor (10(6)) representing the relative inefficiency of DNA uptake by oral administration. This factor was then applied to the WHO recommended parenteral limit of 10 ng/dose to determine a corresponding upper limit on the level of residual Vero cell DNA for an oral vaccine of 10 mg. As a conservative approach, this empirically determined limit was reduced 100-fold to 100 microg. Thus, the results of this animal study, together with additional evidence in the literature, support a residual DNA safety limit of 100 microg per dose for an oral vaccine produced on a continuous cell line.

Mutagenesis approaches to deduce structure-function relationships in terpene synthases

This review highlights mutagenesis studies of terpene synthases, specifically sesquiterpene synthases and oxidosqualene cyclases. Mutagenesis studies of these enzymes have provided mechanistic insights, structure-function relationships for specific enzymatic residues, novel terpene structures and enzymes with novel activities. The literature through 2002 is reviewed and 113 references cited.

Metabolic engineering to produce sesquiterpenes in yeast

[reaction: see text] Presented here is a metabolically engineered yeast strain that produces sesquiterpenes. Epi-cedrol synthase expressed in a native yeast strain converted endogenous farnesyl pyrophosphate to 90 microg/L epi-cedrol. This system was genetically modified to increase foreign terpene yields to 370 microg/L. The best yields were obtained by overexpressing a truncated 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in a upc2-1 mating type a background. This system allows sufficient production to characterize novel sesquiterpene synthase genes.

Design and evaluation of a tryptophanless RecA protein with wild type activity

The C-terminal domain of the Escherichia coli RecA protein contains two tryptophan residues whose native fluorescence emission provides an interfering background signal when other fluorophores such as 1,N(6)-ethenoadenine, 2-aminopurine and other tryptophan residues are used to probe the protein's activities. Replacement of the wild type tryptophans with nonfluorescent residues is not trivial because one tryptophan is highly conserved and the C-terminal domain functions in both DNA binding as well as interfilament protein-protein contact. We undertook the task of creating a tryptophanless RecA protein with WT RecA activity by selecting suitable amino acid replacements for Trp290 and Trp308. Mutant proteins were screened in vivo using assays of SOS induction and cell survival following UV irradiation. Based on its activity in these assays, the W290H-W308F W-less RecA was purified for in vitro characterization and functioned like WT RecA in DNA-dependent ATPase and DNA strand exchange assays. Spectrofluorometry indicates that the W290H-W308F RecA protein generates no significant emission when excited with 295-nm light. Based on its ability to function as wild type protein in vivo and in vitro, this dark RecA protein will be useful for future fluorescence experiments.

An EXAFS study of zinc coordination in microbial cells

Five microbes were isolated from metal amended enrichment cultures derived from the sediments of a lake contaminated by a zinc smelter. Each of these organisms was grown in pure culture in the presence of zinc. Quick Extended X-ray Absorption Fine Structure (QEXAFS) spectroscopy was used to investigate the average coordination environment of the zinc associated with the microbial biomass. Fitting of the first coordination shell of zinc shows that significant differences exist for each microbial species examined. The coordination environment of zinc varies between sulfurs to six-fold nitrogen/oxygen. with two microbial strains showing mixed coordination shells. Further study is required in order to characterize these sites and their locations within the cell.

Thiosulfate disproportionation by Desulfotomaculum thermobenzoicum

Desulfotomaculum thermobenzoicum, but not Desulfotomaculum nigrificans, Desulfotomaculum ruminis, or Desulfosporosinus orientis, grew by disproportionation of thiosulfate, forming stoichiometric amounts of sulfate and sulfide; sulfite was not disproportionated. The addition of acetate enhanced growth and thiosulfate disproportionation by D. thermobenzoicum compared to those observed with thiosulfate alone.

Syntrophus aciditrophicus sp. nov., a new anaerobic bacterium that degrades fatty acids and benzoate in syntrophic association with hydrogen-using microorganisms

Strain SBT is a new, strictly anaerobic, gram-negative, nonmotile, non-sporeforming, rod-shaped bacterium that degrades benzoate and certain fatty acids in syntrophic association with hydrogen/formate-using microorganisms. Strain SBT produced approximately 3 mol of acetate and 0.6 mol of methane per mol of benzoate in coculture with Methanospirillum hungatei strain JF1. Saturated fatty acids, some unsaturated fatty acids, and methyl esters of butyrate and hexanoate also supported growth of strain SBT in coculture with Desulfovibrio strain G11. Strain SBT grew in pure culture with crotonate, producing acetate, butyrate, caproate, and hydrogen. The molar growth yield was 17 +/- 1 g cell dry mass per mol of crotonate. Strain SBT did not grow with fumarate, iron(III), polysulfide, or oxyanions of sulfur or nitrogen as electron acceptors with benzoate as the electron donor. The DNA base composition of strain SBT was 43.1 mol% G+C. Analysis of the 16 S rRNA gene sequence placed strain SBT in the delta-subdivision of the Proteobacteria, with sulfate-reducing bacteria. Strain SBT was most closely related to members of the genus Syntrophus. The clear phenotypic and genotypic differences between strain SBT and the two described species in the genus Syntrophus justify the formation of a new species, Syntrophus aciditrophicus.