Functional aging trajectories of older cancer survivors: a latent growth analysis of the US Health and Retirement Study

PURPOSE

We aimed to identify prototypical functional aging trajectories of US cancer survivors aged 50 and older, overall and stratified by sociodemographic and health-related characteristics.

METHODS

Data were from 2986 survivors of a first incident cancer diagnosis (except non-melanoma skin cancer) after age 50 in the population representative U.S. Health and Retirement Study from 1998-2016. Cancer diagnoses, episodic memory function, and activity of daily living (ADL) limitations were assessed at biennial study interviews. Using time of cancer diagnosis as the baseline, we used group-based trajectory modeling to identify trajectories of memory function and ADL limitations following diagnosis.

RESULTS

We identified five memory loss trajectories (high: 8.4%; medium-high: 18.3%; medium-low: 21.5%; low: 25.5%; and, very low: 26.2%), and four ADL limitation trajectories (high/increasing limitations: 18.7%; medium limitations: 18.7%; low limitations: 8.14%; no limitations: 60.0). The high memory loss and high/increasing ADL limitation trajectories were both characterized by older age, being female (52% for memory, 58.9% for ADL), having lower pre-cancer memory scores, and a higher prevalence of pre-cancer comorbidities including stroke (30.9% for memory and 29.7% for ADL), hypertension (64.7% for memory and 69.8 for ADL), and depressive symptoms. In joint analyses, we found that generally those with higher memory were more likely to have fewer ADL limitations and vice versa.

CONCLUSION

Older cancer survivors experience heterogeneous trajectories of functional aging that are largely characterized by comorbidities prior to diagnosis.

IMPLICATION FOR CANCER SURVIVORS

Results can help identify older cancer survivors at increased risk for accelerated functional decline.

Barriers, facilitators, and recommendations for sexual orientation and gender identity data collection in community oncology practices

BACKGROUND

Sexual orientation and gender identity (SOGI) data collection in community oncology practices is critical to identify and address cancer inequities, but less than 20% of NCI Community Oncology Research Program (NCORP)-affiliated practices regularly collect SOGI data despite widespread recommendations. We evaluated multilevel barriers and facilitators for SOGI data collection at NCORP practices.

METHODS

We conducted 14 semi-structured interviews at seven purposefully sampled NCORP oncology practices. We interviewed one clinician (oncologist, advanced practice provider) and one clinic staff member per practice. Thematic analysis informed by the Consolidated Framework for Implementation Research (CFIR) was conducted to identify barriers and facilitators.

RESULTS

Thematic saturation occurred after interviews at six practices and was confirmed with interviews at an additional practice. Participants highlighted multilevel barriers including low levels of understanding, information technology infrastructure, and perceived low relative priority. Not understanding the role of SOGI data in oncology care contributed to cis-heteronormative culture. At the clinic level, this culture coincided with a lack of processes and policies for collecting SOGI from all patients. At the care team level, perceived irrelevance to oncology care was related to discomfort asking SOGI, fear of patient discomfort, and limited awareness of SOGI in electronic health records. Suggested solutions included: normalizing asking SOGI questions, giving patients privacy to complete SOGI, and clarifying clinical relevance.

CONCLUSIONS

SOGI data collection barriers stemmed from perceptions that SOGI disclosure does not influence care quality. Oncology teams may benefit from training on culturally sensitive SOGI collection, education on SOGI data relevance to oncology practices, and support for implementing SOGI data collection policies.

Primary care provider attitudes about and tendency to use non-recommended surveillance tests after curative breast cancer treatment

PURPOSE

Little is known about the factors contributing to the receipt of non-recommended surveillance testing among early-stage breast cancer survivors. We assessed primary care providers (PCP) attitudes about and tendency to order non-recommended surveillance testing for asymptomatic early-stage breast cancer survivors post-adjuvant chemotherapy.

METHODS

A stratified random sample of PCPs identified by early-stage breast cancer survivors were surveyed (N = 518, 61% response rate). PCPs were asked how likely they would be to order bone scans, imaging and/or tumor marker testing using a clinical vignette of an early-stage asymptomatic patient where these tests are non-recommended. A composite tendency to order score was created and categorized by tertiles (low, moderate, high). PCP-reported factors associated with high and moderate tendency to order non-recommended testing (vs. low) were estimated using multivariable, multinomial logistic regression.

RESULTS

In this sample, 26% reported a high tendency to order non-recommended surveillance tests during survivorship for early-stage breast cancer survivors. PCPs who identified as family practice physicians and PCPs reporting more confidence in ordering surveillance testing were more likely to report a high tendency to order non-recommended testing (vs. low) ((aOR family practice 2.09, CI 1.2, 3.8; aOR more confidence 1.9, CI 1.1, 3.3).

CONCLUSIONS

In this population-based sample of PCPs caring for breast cancer survivors, over a quarter of PCPs reported they would order non-recommended surveillance testing for asymptomatic early-stage breast cancer survivors. Efforts to better support PCPs and disseminate information about appropriate surveillance for cancer survivors are warranted.

Trends in hospice referral timing and location among individuals dying of ovarian cancer: persistence of missed opportunities

OBJECTIVE

To evaluate trends, racial disparities, and opportunities to improve the timing and location of hospice referral for women dying of ovarian cancer.

METHODS

This retrospective claims analysis included 4258 Medicare beneficiaries over age 66 diagnosed with ovarian cancer who survived at least 6 months after diagnosis, died between 2007 and 2016, and enrolled in a hospice. We examined trends in timing and clinical location (outpatient, inpatient hospital, nursing/long-term care, other) of hospice referrals and associations with patient race and ethnicity using multivariable multinomial logistic regression.

RESULTS

In this sample, 56% of hospice enrollees were referred to a hospice within a month of death, and referral timing did not vary by patient race. Referrals were most commonly inpatient hospital (1731 (41%) inpatient, 703 (17%) outpatient, 299 (7%) nursing/long-term care, 1525 (36%) other), with a median of 6 inpatient days prior to hospice enrollment. Only 17% of hospice referrals were made in an outpatient clinic, but participants had a median of 1.7 outpatient visits per month in the 6 months prior to hospice referral. Referral location varied by patient race, with non-Hispanic black people experiencing the most inpatient referrals (60%). Hospice referral timing and location trends did not change between 2007 and 2016. Compared with individuals referred to a hospice in an outpatient setting, individuals referred from an inpatient hospital setting had more than six times the odds of a referral in the last 3 days of life (OR=6.5, 95% CI 4.4 to 9.8) versus a referral more than 90 days before death.

CONCLUSION

Timeliness of hospice referral is not improving over time despite opportunities for earlier referral across multiple clinical settings. Future work delineating how to capitalize on these opportunities is essential for improving the timeliness of hospice care.

“It really does not matter to me, they can be two purple unicorns”: Barriers and facilitators to sexual orientation and gender identity (SOGI) measurement in the NCI Community Oncology Research Program (NCORP)

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Background: Despite recommendations from numerous clinical bodies (e.g., ASCO), less than 20% of NCORP-affiliated practices regularly collect SOGI data. This gap compromises the ability to identify and correct care inequities experienced by sexual and gender minority (SGM) individuals. Therefore, we evaluated provider- and clinic- level barriers and facilitators to SOGI collection at NCORP practices across the US. Methods: We conducted 14 interviews across seven NCORP oncology practices via Zoom. We purposefully sampled to ensure geographic, racial, and ethnic diversity of patient populations. We interviewed one clinician (oncologist, advanced practice provider) and one clinic staff member per practice. The Consolidated Framework for Implementation Research (CFIR) informed thematic analysis that identified barriers and facilitators to SOGI data collection. Interviews were recorded, transcribed, and coded by two coders who adjudicated any discordance. Analyses were conducted in NVivo. Results: Thematic saturation occurred after interviews at six practices, with interviews at the seventh practice confirming saturation. Participants represented five geographic regions and included three Minority Underserved practices and two rural practices. Several organizational context characteristics influenced SOGI data collection: access to knowledge, information technology infrastructure, staff processes, and perceived relative priority of SOGI for an oncology visit. All oncologists expressed a low relative priority of sexual orientation data for oncology care. Gender identity had higher priority because it influences how clinicians should address patients. At the clinic level, this low relative priority coincides with a lack of processes and policies for collecting SOGI from all patients. At the oncology care team level, perceived irrelevance to oncology care was related to discomfort in asking SOGI, fear of patient discomfort, and limited awareness of SOGI in electronic health records. Suggested solutions included: normalizing asking SOGI questions, giving patients privacy to complete SOGI, and clarifying relevance of SOGI for clinical purposes. Understanding how SOGI improves patient experiences was a facilitator for collection. Conclusions: Within this NCORP practice sample, SOGI data collection barriers included clinician-perceived low relative priority for collection, and perceptions that SOGI disclosure does not influence care quality, despite most interviewees expressing a strong desire to show respect to patients and provide high quality cancer care. Oncology teams may benefit from training on culturally sensitive SOGI collection, education on SOGI data relevance to oncology practices, and support for implementing SOGI data collection policies.

Physician Influence on Variation in Receipt of Aggressive End-of-Life Care Among Women Dying of Ovarian Cancer

PURPOSE

End-of-life care for women with ovarian cancer is persistently aggressive, but factors associated with overuse are not well understood. We evaluated physician-level variation in receipt of aggressive end-of-life care and examined physician-level factors contributing to this variation in the SEER-Medicare data set.

METHODS

Medicare beneficiaries with ovarian cancer who died between 2000 and 2016 were included if they were diagnosed after age 66 years, had complete Medicare coverage between diagnosis and death, and had outpatient physician evaluation and management for their ovarian cancer. Using multilevel logistic regression, we examined physician variation in no hospice enrollment, late hospice enrollment (≤ 3 days), > 1 emergency department visit, an intensive care unit stay, terminal hospitalization, > 1 hospitalization, receiving a life-extending or invasive procedure, and chemotherapy (in the last 2 weeks).

RESULTS

In this sample of 6,288 women, 51% of women received at least one form of aggressive end-of-life care. Most common were no hospice enrollment (28.9%), an intensive care unit stay (18.6%), and receipt of an invasive procedure (20.7%). For not enrolling in hospice, 9.9% of variation was accounted for by physician clustering (P < .01). Chemotherapy had the highest physician variation (12.4%), with no meaningful portion of the variation explained by physician specialty, volume, region, or patient characteristics.

CONCLUSION

In this study, a meaningful amount of variation in aggressive end-of-life care among women dying of ovarian cancer was at the physician level, suggesting that efforts to improve the quality of this care should include interventions aimed at physician practices and decision making in end-of-life care.

New directions in cancer and aging: State of the science and recommendations to improve the quality of evidence on the intersection of aging with cancer control

Background

The global population of older cancer survivors is growing. However, the intersections of aging‐related health risks across the cancer control continuum are poorly understood, limiting the integration of aging into cancer control research and practice. The objective of this study was to review the state of science and provide future directions to improve the quality of evidence in 6 priority research areas in cancer and aging.

Methods

The authors identified priority research areas in cancer and aging through an evidence‐based Research Jam process involving 32 investigators and trainees from multiple disciplines and research centers in aging and cancer; then, they conducted a narrative review of the state of the science and future directions to improve the quality of evidence in these research areas. Priority research areas were defined as those in which gaps in scientific evidence or clinical practice limit the health and well‐being of older adults with cancer.

Results

Six priority research areas were identified: cognitive and physical functional outcomes of older cancer survivors, sampling issues in studies of older cancer survivors, risk and resilience across the lifespan, caregiver support and well‐being, quality of care for older patients with cancer, and health disparities. Evidence in these areas could be improved through the incorporation of bias reduction techniques into longitudinal studies of older cancer survivors, novel data linkage, and improved representation of older adults in cancer research.

Conclusions

The priority research areas and methodologies identified here may be used to guide interdisciplinary research and improve the quality of evidence on cancer and aging.

The population of older cancer survivors is growing, yet the effects of aging‐related health risks across the cancer control continuum remain poorly understood. This article identifies research areas that may be used to guide interdisciplinary research and improve the quality of evidence on cancer and aging.

Validation of self-reported cancer diagnoses using Medicare diagnostic claims in the U.S. Health and Retirement Study, 2000-2016

BACKGROUND

The US Health Retirement Study (HRS) is an ongoing population-representative cohort of US adults aged >50 with rich data on health during aging. Self-reported cancer diagnoses have been collected since 1998, but they have not been validated. We compared self-reported cancer diagnoses in HRS interviews against diagnostic claims from linked Medicare records.

METHODS

Using HRS-Medicare linked data, we examined the validity of first incident cancer diagnoses self-reported in biennial interviews from 2000-2016 against ICD-9 and ICD-10 diagnostic claim records as the gold standard. Data were from 8,242 HRS participants aged {greater than or equal to}65 with 90% continuous enrollment in fee-for-service Medicare. We calculated the sensitivity, specificity, and k for first incident invasive cancer diagnoses (all cancers combined, and each of bladder, breast, colorectal/anal, uterine, kidney, lung, and prostate cancers) cumulatively over the follow-up and at each biennial study interview.

RESULTS

Overall, self-reports of first incident cancer diagnoses from 2000-2016 had 73.2% sensitivity and 96.2% specificity against Medicare claims (k=0.73). For specific cancer types, sensitivities ranged from 44.7% (kidney) to 75.0% (breast), and specificities ranged from 99.2% (prostate) and 99.9% (bladder, uterine, and kidney). Results were similar in sensitivity analyses restricting to individuals with 100% continuous fee-for-service Medicare enrollment and when restricting to individuals with at least 24 months of Medicare enrollment.

CONCLUSION

Self-reported cancer diagnoses in the HRS have reasonable validity for use in population-based research that is maximized with linkage to Medicare.

IMPACT

These findings inform the use of the HRS for population-based cancer and aging research.

Access to primary care and cognitive impairment: results from a national community study of aging Americans

BACKGROUND

Despite a growing burden of Alzheimer's Disease and related dementias (ADRD) in the US, the relationship between health care and cognitive impairment prevention is unclear. Primary care manages risk causing conditions and risk reducing behaviors for dementia, so we examine the association between individual and area-level access to primary care and cognitive impairment in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study.

METHODS

REGARDS participants with a cognitive assessment and vascular measurements at their baseline visit were included in this cross-sectional analysis. Cognitive impairment was defined as a Six-Item Screener (SIS) score < 5. Primary care supply, primary care utilization and emergency department (ED) utilization were measured at the primary care service area (PCSA) level based on participant's address. Individual access to care was self-reported. Models were adjusted for confounding by demographics, socioeconomic status and behavioral risk factors.

RESULTS

Among 25,563 adults, living in a PCSA with low primary care supply was associated with 25% higher odds of cognitive impairment (OR 1.25 CI 1.07-1.45). Not having a regular source of medical care was associated with 14% higher odds of cognitive impairment (OR 1.14 CI 1.02-1.28), and living in a PCSA with high emergency department utilization was associated with 12% higher odds of cognitive impairment (OR 1.12 CI 1.02-1.23).

CONCLUSIONS

Our results are an important first step in understanding how health care may prevent cognitive impairment. They highlight the importance of primary care and suggest future work clarifying its role in preventing cognitive decline is imperative.

Improving the delivery of team-based survivorship care after primary breast cancer treatment through a multi-level intervention: a pilot randomized controlled trial

PURPOSE

We developed and tested a multi-level intervention, ConnectedCancerCare (CCC), which includes a tailored website and appointment reminder system for women with early-stage breast cancer and a provider summary letter sent to their medical oncologist and primary care provider to improve the delivery of team-based survivorship care.

METHODS

We conducted a pilot randomized controlled trial to establish the feasibility and acceptability of CCC. Women diagnosed with stages 0-II breast cancer within one year of completing primary treatment were randomized to CCC (intervention) or a static online survivorship care plan (control). Participants completed baseline and 3-month follow-up surveys online. Post-trial interviews with 5 PCPs, 6 oncology providers, and 8 intervention patients were conducted.

RESULTS

Of the 160 eligible women invited to participate, 66 completed the baseline survey and were randomized (41%) and 54 completed a follow-up survey (83%). Participants in the intervention arm found the CCC content to be acceptable, with 82% reporting it was easy to use and 86% reporting they would recommend it to other patients. Women randomized to CCC (vs. control) more often reported scheduling a PCP follow-up visit (64% vs. 42%), communicating with their PCP about provider roles (67% vs. 18%), and higher mean team-based cancer care knowledge scores (3.7 vs. 3.4).

CONCLUSION

Deploying CCC in medical oncology practices was feasible, and the intervention content was acceptable. CCC shows promise for improving patient knowledge and patient-provider communication about provider roles in team-based cancer care and encouraging patients to engage with their PCP early in the survivorship period.

Continuity of care and receipt of aggressive end of life care among women dying of ovarian cancer

OBJECTIVE

To evaluate the association between post-diagnosis continuity of care and receipt of aggressive end of life care among women dying of ovarian cancer.

METHODS

This retrospective claims analysis included 6680 Medicare beneficiaries over age 66 with ovarian cancer who survived at least one year after diagnosis, had at least 4 outpatient evaluation and management visits and died between 2000 and 2016. We calculated the Bice-Boxerman Continuity of Care Index (COC) for each woman, and split COC into tertiles (high, medium, low). We compared late or no hospice use, >1 emergency department (ED) visit, intensive care unit (ICU) admission, >1 hospitalization, terminal hospitalization, chemotherapy, and invasive and/or life extending procedures among women with high or medium vs. low COC using multivariable adjusted logistic regression.

RESULTS

In this sample, 49.8% of women received aggressive care in the last month of life. Compared to women with low COC, women with high COC had 66% higher odds of chemotherapy (adjusted OR 1.66 CI 1.23-2.24) in the last two weeks of life. Women with high COC also had 16% greater odds of not enrolling in hospice compared to women with low COC (adjusted OR 1.16 CI 1.01-1.33). COC was not associated with late enrollment in hospice, hospital utilization, or aggressive procedures.

CONCLUSIONS

COC at the end of life is complicated and may pose unique challenges in providing quality end of life care. Future work exploring the specific facets of continuity associated with quality end of life care is needed.

Trends and racial disparities in aggressive end-of-life care for a national sample of women with ovarian cancer

BACKGROUND

The clinical landscape has moved toward less aggressive end-of-life care for women with ovarian cancer. However, whether there has been a decline in the use of aggressive end-of-life services is unknown. The authors evaluated current national trends and racial disparities in end-of-life care among women with ovarian cancer using the Surveillance, Epidemiology, and End Results-Medicare-linked data set.

METHODS

In total, 7756 Medicare beneficiaries aged >66 years with ovarian cancer who died between 2007 and 2016 were identified. The authors examined trends and racial disparities in late hospice or no hospice use, >1 emergency department (ED) visit, intensive care unit admission, >1 hospitalization, terminal hospitalization, chemotherapy, and invasive and/or life-extending procedures using multivariable logistic regression.

RESULTS

The median hospice length of stay did not change over time; however, women were increasingly admitted to the intensive care unit and had multiple ED visits in the last month of life (P < .001). Not enrolling in hospice at the end of life and terminal hospitalizations decreased over time (P < .001). Non-White women were more likely to receive aggressive end-of-life care, particularly for hospital-related utilization and life-extending procedures, whereas non-Hispanic Black women were more likely to have >1 ED visit (odds ratio, 2.04; 95% CI, 1.57-2.64) or life-extending procedures (odds ratio, 1.89; 95% CI, 1.45-2.48) compared with non-Hispanic White women.

CONCLUSIONS

Despite clinical guidelines and increasing emphasis on reducing aggressive end-of-life care, the use of aggressive end-of-life care for women with ovarian cancer persists, and care is most aggressive for non-White women.

Perceived discrimination, trust in physicians, and prolonged symptom duration before ovarian cancer diagnosis in the African American Cancer Epidemiology Study

BACKGROUND

Discrimination and trust are known barriers to accessing health care. Despite well-documented racial disparities in the ovarian cancer care continuum, the role of these barriers has not been examined. This study evaluated the association of everyday discrimination and trust in physicians with a prolonged interval between symptom onset and ovarian cancer diagnosis (hereafter referred to as prolonged symptom duration).

METHODS

Subjects included cases enrolled in the African American Cancer Epidemiology Study, a multisite case-control study of epithelial ovarian cancer among black women. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for associations of everyday discrimination and trust in physicians with a prolonged symptom duration (1 or more symptoms lasting longer than the median symptom-specific duration), and it controlled for access-to-care covariates and potential confounders.

RESULTS

Among the 486 cases in this analysis, 302 women had prolonged symptom duration. In the fully adjusted model, a 1-unit increase in the frequency of everyday discrimination increased the odds of prolonged symptom duration 74% (OR, 1.74; 95% CI, 1.22-2.49), but trust in physicians was not associated with prolonged symptom duration (OR, 0.86; 95% CI, 0.66-1.11).

CONCLUSIONS

Perceived everyday discrimination was associated with prolonged symptom duration, whereas more commonly evaluated determinants of access to care and trust in physicians were not. These results suggest that more research on the effects of interpersonal barriers affecting ovarian cancer care is warranted.

Preclinical pharmacology of CP-424,391, an orally active pyrazolinone-piperidine [correction of pyrazolidinone-piperidine] growth hormone secretagogue

Growth hormone secretagogues (GHSs) represent attractive therapeutic alternatives to recombinant growth hormone (GH), given their ability to amplify pulsatile hormone secretion in a relatively physiologic manner. CP-424,391 (391) is a novel, orally active pyrazolinone-piperidine [corrected] GHS. In rat pituitary cell cultures, 391 stimulated GH release with an EC50 = 3 nM. The addition of 391 to rat pituitary cells activated intracellular calcium signaling but did not elevate intracellular cyclic adenosine monophosphate (cAMP). 391 also modulated the effects of GH-releasing hormone and somatostatin on pituitary cell GH-release and intracellular signaling. In nonpituitary cell lines, the ability of 391 to stimulate intracellular signaling was dependent on the expression of recombinant human GHS receptor. Acute administration of 391 to anesthetized rats or to conscious dogs induced pulsatile release of G H in a dose-dependent manner. Plasma insulin-like growth factor-I (IGF-I) was elevated progressively over a 5-d course of daily oral dosing in dogs. Chronic oral administration of 391 augmented body weight gain in rats and dogs. Thus, the peptidomimetic GHS 391 has potential utility for the treatment of clinical conditions that could benefit from systemic augmentation of GH and IGF-I levels.

The Bacillus thuringiensis vegetative insecticidal protein Vip3A lyses midgut epithelium cells of susceptible insects

The Vip3A protein is a member of a newly discovered class of vegetative insecticidal proteins with activity against a broad spectrum of lepidopteran insects. Histopathological observations indicate that Vip3A ingestion by susceptible insects such as the black cutworm (Agrotis ipsilon) and fall armyworm (Spodoptera frugiperda) causes gut paralysis at concentrations as low as 4 ng/cm2 of diet and complete lysis of gut epithelium cells resulting in larval death at concentrations above 40 ng/cm2. The European corn borer (Ostrinia nubilalis), a nonsusceptible insect, does not develop any pathology upon ingesting Vip3A. While proteolytic processing of the Vip3A protein by midgut fluids obtained from susceptible and nonsusceptible insects is comparable, in vivo immunolocalization studies show that Vip3a binding is restricted to gut cells of susceptible insects. Therefore, the insect host range for Vip3A seems to be determined by its ability to bind gut cells. These results indicate that midgut epithelium cells of susceptible insects are the primary target for the Vip3A insecticidal protein and that their subsequent lysis is the primary mechanism of lethality. Disruption of gut cells appears to be the strategy adopted by the most effective insecticidal proteins.

Vip3A, a novel Bacillus thuringiensis vegetative insecticidal protein with a wide spectrum of activities against lepidopteran insects

A novel vegetative insecticidal gene, vip3A(a), whose gene product shows activity against lepidopteran insect larvae including black cutworm (Agrotis ipsilon), fall armyworm (Spodoptera frugiperda), beet armyworm (Spodoptera exigua), tobacco budworm (Heliothis virescens), and corn earworm (Helicoverpa zea) has been isolated from Bacillus thuringiensis strain AB88. VIP3-insecticidal gene homologues have been detected in approximately 15% of Bacillus strains analyzed. The sequence of the vip3A(b) gene, a homologue of vip3A(a) isolated from B. thuringiensis strain AB424 is also reported. Vip3A(a) and (b) proteins confer upon Escherichia coli insecticidal activity against the lepidopteran insect larvae mentioned above. The sequence of the gene predicts a 791-amino acid (88.5 kDa) protein that contains no homology with known proteins. Vip3A insecticidal proteins are secreted without N-terminal processing. Unlike the B. thuringiensis 5-endotoxins, whose expression is restricted to sporulation, Vip3A insecticidal proteins are expressed in the vegetative stage of growth starting at mid-log phase as well as during sporulation. Vip3A represents a novel class of proteins insecticidal to lepidopteran insect larvae.

High-performance liquid chromatographic assay with electrochemical detection for azithromycin in serum and tissues

High-performance liquid chromatographic methods using reversed-phase chromatography and electrochemical detection have been developed for the quantitation of azithromycin in serum and tissues of laboratory animals and humans. Serum sample preparation involved addition of internal standard, alkalinization, and solvent extraction. Tissue sample preparation involved Polytron homogenization in acetonitrile containing internal standard, evaporation of the supernatant, alkalinization of the residue, and solvent extraction. Serum samples were chromatographed on an alkylphenyl-bonded silica column eluted with pH 6.8-7.2 mobile phase with a dual-electrode coulometric detector operated in the oxidative screen mode. Serum and tissue samples were chromatographed on a gamma RP-1 alumina column with pH 11 mobile phase with a glassy carbon amperometric detector. Recovery of azithromycin was 87% from serum and 85% from tissues. Linear standard curves were prepared in serum over two concentration ranges (0.01-0.20 and 0.20-2.0 micrograms/ml) and in tissues over several concentration ranges (0.1-2, 1-10, 10-100, and 100-1000 micrograms/g). In serum and tissues, intra- and inter-assay precision ranged from 1 to 8% and 4 to 11%, respectively. The tissue assay has been applied to liver, kidney, lung, spleen, muscle, fat, brain, tonsil, lymph nodes, eye, prostate and other urological tissues, and gynecological tissues.

Nitrate effects on nitrate reductase activity and nitrite reductase mRNA levels in maize suspension cultures

Nitrate reductase (NR) activity and nitrite reductase (NiR) mRNA levels were monitored in Black Mexican Sweet maize (Zea mays L.) suspension cultures after the addition of nitrate. Maximal induction occurred with 20 millimolar nitrate and within 2 hours. Both NR and NiR mRNA were transiently induced with levels decreasing after the 2 hours despite the continued presence of nitrate in the medium. Neither ammonia nor chlorate prevented the induction of NR. Furthermore, removal of nitrate, followed by its readdition 22 to 48 hours later, did not result in reinduction of activity or message. NR was synthesized de novo, since cycloheximide completely blocked its induction. Cycloheximide had no effect on the induction of NiR mRNA or on the transient nature of its induction. These results are similar to those reported previously for maize seedlings.