Risk of Radiation-Associated Secondary Malignancies among Patients with Breast Cancer Harboring TP53 Germline Variants

PURPOSE/OBJECTIVE(S)

Radiation-associated malignancies are rare and poorly understood. TP53 encodes a multifunctional protein that maintains genome integrity and is the most common somatically mutated gene in cancer. Germline pathogenic variants of TP53 predispose carriers to several cancers comprising the Li-Fraumeni syndrome. It is hypothesized that carriers are also at increased risk of radiotherapy (RT)-associated secondary malignancies; however, reports are mixed. We evaluated the risk of secondary malignancies after breast RT among patients with Li-Fraumeni syndrome.

MATERIALS/METHODS

This multi-institutional cohort study included carriers of TP53 germline variants who underwent surgical treatment for breast cancer between 1980 and 2020. Patients were stratified based on germline TP53 classification (pathogenic variants [PV] vs variants of uncertain significance [VUS]). The primary outcome of interest was the cumulative incidence risk of developing an in-field secondary cancer after radiotherapy for primary breast carcinoma.

RESULTS

Ninety-one patients (57 PV and 34 VUS) were evaluated with a median age of 36 years (interquartile range [IQR] 31, 42) and a median follow up of 7.9 years (IQR 4.7, 14.4). Among those with PV who received RT (n = 22), 4 secondary non-breast cancers developed in the radiation field (15-year cumulative incidence 19% [95% CI: 4-43%]), whereas, among those with PV who did not receive RT (n = 35), 0 secondary non-breast cancers were observed in the treated breast (15-year cumulative incidence 0%; p = 0.043). We observed 3 radiation-associated sarcomas among patients with PV who received RT (15-year risk 12% [95% CI 2-33%]) compared with 0 among those who did not receive RT (p = 0.08). No RT-associated sarcomas were observed among 18 patients with TP53 VUS who received RT. RT was not associated with overall survival, despite higher T and N breast cancer stage among those receiving RT (p = 0.33). As expected, patients with PV were more likely than those with VUS to develop any secondary cancer following breast cancer treatment (15-year risk: 54% [95% CI: 33-72%] vs. 14% [95% CI: 3-36%]).

CONCLUSION

Carriers of pathogenic variants of TP53 are at elevated risk of developing secondary malignancies after breast cancer treatment. This population is at particular risk of developing in-field secondary cancers following RT. This iatrogenic risk must be weighed against the anticipated therapeutic benefit of tumor control. Shared decision making is crucial in the radiotherapeutic management of breast cancer patients harboring the Li-Fraumeni syndrome.

Success of Liquid Tumor Biopsy in Men with Metastatic Prostate Cancer According to Self-Identified Race

PURPOSE/OBJECTIVE(S)

Liquid biopsy using cell-free DNA (cfDNA) is increasingly used to identify somatic prostate cancer (PrCa) alterations when tissue biopsy of a metastatic lesion is infeasible or impractical. High-risk somatic alterations identified by cfDNA have been recently shown to predict the benefit of metastasis-directed therapy with stereotactic body radiation therapy in PrCa. However, given the older age of PrCa patients, liquid biopsy is often contaminated with alterations related to clonal hematopoiesis of indeterminate potential (CHIP), generating uncertainty in the clinical utility of the results. Given the higher incidence and aggressiveness of metastatic PrCa in Black men, we sought to determine if the success of cfDNA testing varied by race in a large and diverse cohort of United States Veterans with metastatic PrCa, hypothesizing that race would not influence the success of cfDNA testing.

MATERIALS/METHODS

Veterans with metastatic PrCa underwent next-generation sequencing of cfDNA biopsy specimens through the VA National Precision Oncology Program from February 2019 to November 2022. Successful identification of PrCa with cfDNA testing was defined as the identification of an alteration in one or more PrCa-related related genes in the gene panel tested (AR, CDK12, SPOP, MED12, CCND1, BRAF, AKT1, TMPRSS2, ERG, ETV1, and ETV4). Univariate logistic regression was employed to explore the association between patient self-identified race, as well as other patient and disease-specific factors at the time of cfDNA biopsy, with the likelihood of yielding a successful cfDNA biopsy result.

RESULTS

A total of 2066 cfDNA tests from 1985 Veterans were related to a diagnosis of PrCa, passed quality control measures, and were linkable to patient-level demographics. Median age at testing was 74, median PSA at testing was 22.7, median PSA doubling time (PSADT) was 3.6 months, and median Gleason score was 8. 57% of Veterans self-identified as White, 33% as Black, and 10% as Other. Eight hundred fourteen (39%) tests were deemed successful by finding a PrCa related gene alteration. Among successful tests, the most frequently encountered alterations were AR alterations in 60.4% White men and 33.9% Black men (p = 0.72), followed by TMPRSS2 alterations in 70.3% White men and 22.0% Black men (p<0.001). Despite a lower rate of PrCa-specific alterations in Black men, on univariate analysis, Veteran self-identified race was not associated with successful cfDNA testing (OR 0.95, 95% CI 0.78-1.14, p = 0.6), whereas PSA in quintiles 2-4, PSADT <12 months, and unit increase in Gleason score were associated with successful cfDNA testing (p<0.01 for all).

CONCLUSION

Successful cfDNA biopsy in metastatic PrCa is associated with PSA and PSADT, but not related to patient self-identified race. In appropriate clinical scenarios, patients who self-identify as Black or White are equally likely to have PrCa-specific alterations detected on cfDNA testing when evaluating metastatic PrCa patients for local and systemic therapies.

197 IMPROVING THE ASSESSMENT OF VISION IN OLDER ADULTS AT RISKS OF FALLS AT A DAY REHABILITATION CLINIC

Background

Assessment of vision is a key component of multifactorial falls prevention programmes. However, the National Audit of Inpatient Falls (2015) found less than half of older adults had a vision assessment when admitted to hospital. We suspected vision assessment could also be improved for patients attending our outpatient Day Rehabilitation Unit who were falling or at risk of falls.

Methods

21 outpatients were audited initially, with determination of baseline characteristics including age and Rockwood frailty score. We assessed whether past ophthalmological history was documented, whether the patient wore glasses and whether they had had a recent eye test in the community. Finally, documentation regarding visual examination was audited; this comprised range of eye movement, visual fields and visual acuity assessments. We adapted the clinic proforma to include a specific section on ophthalmology history and visual assessment; 14 patients were re-audited following intervention.

Results

Our two groups were relatively similar: mean age of 80 in the initial audit and 78 in the subsequent audit. Both groups had an average Rockwood score of 5. Improvements were noted in documentation regarding previous eye testing (33.3% - 86%), testing of eye movements (71.4% - 100%, and testing of visual fields (66.7% - 93%). There remained no testing of visual acuity following intervention.

Conclusion

A dedicated falls proforma targeting specific risk factors for falls improves identification and assessment of those risks. This enables targeted intervention and referral to be made to improve patient outcomes. For further improvement we would recommend educating the multidisciplinary team on how to test for visual acuity in the outpatient setting.

POS0579 ABSENCE OF ASSOCIATION BETWEEN ABATACEPT EXPOSURE LEVELS AND INITIAL INFECTION IN PATIENTS WITH RA: A POST HOC ANALYSIS OF THE RANDOMIZED, PLACEBO-CONTROLLED AVERT-2 STUDY

Background

Infections are the most commonly reported AE observed in patients with RA treated with immunosuppressive therapies and can be clinically significant. A recent review reported differences in the risk of infection for some biologics such as tocilizumab and TNF inhibitors.1 Abatacept selectively modulates T-cell co-stimulation and is approved for the treatment of RA. In patients with polyarticular-course juvenile idiopathic arthritis, no association was found between higher serum abatacept exposure and the incidence of infection.2 This has not been evaluated for adult patients with RA.

Objectives

To determine if higher serum abatacept exposure during treatment with SC abatacept was associated with increased risk of infection in adult patients with RA.

Methods

AVERT-2 (Assessing Very Early Rheumatoid arthritis Treatment-2) was a randomized, placebo-controlled study of SC abatacept + MTX vs abatacept placebo + MTX in MTX-naive, anti-citrullinated protein antibody–positive patients with early, active RA.3 A post hoc population pharmacokinetic (PK) analysis was performed using PK-evaluable patient data from the induction period (year 1) of AVERT-2. Association between steady-state abatacept exposure (min plasma concentration [Cmin], max plasma concentration [Cmax], and average plasma concentration [Cavg]) and first infection was evaluated using Kaplan–Meier plots of probability vs time on treatment by abatacept exposure quartiles and Cox proportional-hazards models.

Results

PK of SC abatacept was defined as a linear 2-compartment model with first-order absorption and first-order elimination. The findings of the updated PK analysis were consistent with those reported in prior population analyses of abatacept PK in adults with RA. The final model included effects of baseline body weight, estimated glomerular filtration rate, sex, age, albumin, MTX use, NSAID use, SJC, and race on abatacept clearance. The only covariate with a clinically relevant effect was higher body weight, which caused an increase in clearance and volume. Infections occurred in a total of 330/693 (47.6%; serious, 1.6%) patients treated with abatacept, and 134/301 (44.5%; serious, 1.3%) with placebo during the first year of AVERT-2. In patients taking abatacept, the mean (SD) study exposure to abatacept was 376 (60) days, while mean (SD) prednisone equivalent dose was 6.7 (3.8) mg/day and mean (SD) MTX dose was 9.6 (3.0) mg/week. No exposure–response relationship was observed between the probability of first infection and steady-state abatacept exposure quartiles (Cavg, Cmin, and Cmax), or compared with placebo (Figure 1A–C). Kaplan–Meier assessment also showed no increase in risk of infection with concomitant use of MTX and glucocorticoids.

Conclusion

No association was found between initial infection and steady-state abatacept exposure (Cavg, Cmin, Cmax) or MTX and glucocorticoid use in patients with RA treated with SC abatacept.

References

[1]Jani M, et al. Curr Opin Rheumatol 2019;31:285–92.

[2]Ruperto N, et al. J Rheumatol 2021;48:1073–81.

[3]Emery P, et al. Arthritis Rheumatol 2019;71(suppl 10):L11.

Acknowledgements

This study was sponsored by Bristol Myers Squibb. Writing and editorial assistance were provided by Fiona Boswell, PhD, of Caudex, and was funded by Bristol Myers Squibb. Support was provided by Sandra Overfield as Protocol Manager, and Prema Sukumar and Renfang Hwang as Data Science Leads.

Disclosure of Interests

Paul Emery Consultant of: AbbVie, AstraZeneca, Boehringer Ingelheim, Bristol Myers Squibb, Eli Lilly, Galapagos, Gilead, Janssen, Merck Sharp & Dohme, Novartis, Pfizer, Roche, Samsung, Grant/research support from: AbbVie, Bristol Myers Squibb, Eli Lilly, Novartis, Pfizer, Roche, Samsung, Roy Fleischmann Consultant of: Amgen, AbbVie, Bristol Myers Squibb, Gilead, GlaxoSmithKline, Novartis, Pfizer, Grant/research support from: Amgen, AbbVie, Arthrosi, Biosplice, Bristol Myers Squibb, Gilead, GlaxoSmithKline, Horizon, Novartis, Pfizer, Regeneron, TEVA, UCB, Robert Wong Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Karissa Lozenski Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Yoshiya Tanaka Speakers bureau: AbbVie, Amgen, Astellas, AstraZeneca, Boehringer Ingelheim, Bristol Myers Squibb, Chugai, Eisai, Eli Lilly, Gilead, Mitsubishi Tanabe, YL Biologics, Consultant of: AbbVie, Ayumi, Daiichi Sankyo, Eli Lilly, GlaxoSmithKline, Taisho, Sanofi, Grant/research support from: AbbVie, Asahi Kasei, Boehringer Ingelheim, Chugai, Corrona, Daiichi Sankyo, Eisai, Kowa, Mitsubishi Tanabe, Takeda, Vivian Bykerk Consultant of: Amgen, Bristol Myers Squibb, Genzyme Corporation, Gilead, Regeneron, UCB, Grant/research support from: Amgen, Bristol Myers Squibb, Genzyme Corporation, Pfizer, Regeneron, Sanofi Aventis, UCB, Clifton Bingham Consultant of: AbbVie, Bristol Myers Squibb, Eli Lilly, Janssen, Pfizer, Sanofi, Grant/research support from: Bristol Myers Squibb, Thomas Huizinga Speakers bureau: Abblynx, Abbott, Biotest AG, Bristol Myers Squibb, Crescendo Bioscience, Eli Lilly, Epirus, Galapagos, Janssen, Merck, Novartis, Pfizer, Roche, Sanofi- Aventis, UCB, Consultant of: Abblynx, Abbott, Biotest AG, Bristol Myers Squibb, Crescendo Bioscience, Eli Lilly, Epirus, Galapagos, Janssen, Merck, Novartis, Pfizer, Roche, Sanofi- Aventis, UCB, Grant/research support from: Abblynx, Abbott, Biotest AG, Bristol Myers Squibb, Crescendo Bioscience, Eli Lilly, Epirus, Galapagos, Janssen, Merck, Novartis, Pfizer, Roche, Sanofi- Aventis, UCB, Gustavo Citera Speakers bureau: AbbVie, Amgen, Bristol Myers Squibb, Eli Lilly, Janssen, Pfizer, Sandoz, Consultant of: AbbVie, Amgen, Bristol Myers Squibb, Pfizer, Grant/research support from: Pfizer, Yedid Elbez Consultant of: Bristol Myers Squibb, Employee of: Signifience, Vidya Perera Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Bindu Murthy Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Kelly Maxwell Consultant of: Bristol Myers Squibb, Employee of: Cognigen Corporation, Julie Passarell Consultant of: Bristol Myers Squibb, Employee of: Cognigen Corporation, William Hedrich: None declared, Daphne Williams Consultant of: Black Diamond Network, Joule, Syneos, Employee of: Bristol Myers Squibb.

Using the Working Model of Adjustment to Chronic Illness to explain the burden of recurrent urinary tract infection: A survey-based study

Introduction

The treatment of recurrent urinary tract infection (RUTI) with antibiotics is causing concern as patients are often prescribed an inappropriate course of antibiotics, and the recurrence rate remains at 30–44% following treatment (1). Overprescription of antibiotics can also cause antimicrobial resistance. Given the current lack of adequate clinical guidelines for RUTI treatment, it is necessary for this population to adjust to living with a chronic condition, and research suggests that RUTI may be associated with poor mental health and a lower quality of life. Thus, there is a need for a more interdisciplinary approach to understanding RUTI, to inform additional treatment options.

Aim

The current study aimed to use the Working Model of Adjustment to Chronic Illness (WMACI) (see Figure 1) to explore the personal, physical and social burden of RUTI (2).

Methods

A cross-sectional survey was employed, which was informed by existing questionnaires and reviewed by experts including pain specialists (n = 6). 5,078 participants accessed liveutifree.com to seek information regarding their condition and completed the Live UTI Free survey. Participants provided information on their experiences with RUTI (recurrence rate, symptoms, pain intensity, triggers and comorbidity) and the associated burden. Binomial logistic regressions were conducted to assess the effect of RUTI characteristics on the likelihood of experiencing personal, physical and social burden.

Results

RUTI predicted greater likelihood of personal burden (enjoyment of life; enjoyment of favourite activities; mental health) (R² = 18.8 – 20.8, p = &lt;.001), physical burden (sleep; activities of daily living; maintaining a healthy lifestyle; sexual behaviour) (R² = 21.1 – 35.9, p = &lt;.001), and social burden (normal work; finances; relationships with friends and family; relationships with partners) (R² = 17.0 - 25.8, p = &lt;.001), with the burden associated with sexual behaviour showing the largest amount of variance. Rate of recurrence, symptom burden, pain intensity, and having an additional diagnosis of Interstitial Cystitis (IC) were most predictive of participant burden.

Conclusion

RUTI was associated with all areas of burden. Some factors, including pain intensity and having an additional diagnosis of IC, affected a majority of areas. Predicted burden from having an additional diagnosis of IC may be a result of lack of clarity between the two diagnoses, which have shared symptom indicators and rely on urine culture testing, which has been demonstrated to be inaccurate. Misdiagnosis, or a dual diagnosis, may consequently contribute to burden. The WMACI was used to suggest how burden can lead to poor illness adjustment. Limitations of the study were that it did not explore the possibility of misdiagnosis and its impact, or investigate the effects of SES and country-level differences. However, the findings of the study have important clinical implications, as patients worldwide who are suffering with RUTI are required to manage significant burden that is associated with the condition, and this is an important issue which needs to be addressed in primary care settings. An interdisciplinary approach in primary care settings is recommended, which acknowledges the psychosocial burden that persists when treatment fails to resolve physical symptoms.

References

1. Gupta K, Trautner BW. Diagnosis and management of recurrent urinary tract infections in non-pregnant women. BMJ (Online). 2013; 346: f3140.

2. Moss-Morris R. Adjusting to chronic illness: Time for a unified theory. British Journal of Health Psychology. 2013; 681–686.

Abstract PD4-07: PET imaging of PARP-1 expression in breast cancer

18F-FluorThanatrace ([18F]-FTT) is a novel radiotracer shown to quantify Poly [ADP-ribose] polymerase 1 (PARP-1) expression in vitro and in vivo through a receptor-ligand interaction. A recent study at the University of Pennsylvania in women with ovarian cancer demonstrated in vivo visualization of PARP-1 expression in tumors using this radiotracer that closely correlated with an in vitro assay of PARP-1 in tumor tissue (Makvandi, M. J. Clin. Invest. 128:2116, 2018). A radioligand with PARP-1 specificity, [125I]-KX1, was also developed as a companion tool for ex vivo evaluation of PARP-1 expression and PARP inhibitor (PARPi) drug occupancy by radioligand binding assay (Makvandi, M. Cancer Res. 76:4516, 2016). As the first step in validating this biomarker in breast cancer, we performed a prospective clinical trial comparing in vivo [18F]-FTTuptake and ex vivo PARP-1 expression in women with primary breast cancer.

Methods: 24 patients with Stage I-IV primary breast cancer were imaged with [18F]-FTT prior to any therapy including surgery. We correlated in vivo uptake with ex vivo immunohistochemistry (IHC) for PARP-1 and [125I]-KX1 autoradiography in untreated surgical specimens. Tumors were analyzed for alterations in DNA repair genes, copy number-based as well as mutational signatures indicative of homologous recombination deficiency (HRD) and mutational burden, using our established protocol (Maxwell, KN, Nature Commun. 8:319, 2017).

Results: [18F]-FTT uptake was visualized above background in all primary breast tumors and known metastases. Two areas of unexpected uptake revealed an unknown contralateral breast cancer and an ovarian carcinoid, respectively. We expected that uptake might be highest in triple negative breast cancer (TNBC), where PARPi have been most heavily studied. However, a range of tracer uptake was observed in tumors independent of breast cancer subtype (hormone receptor positive/HER2 negative, TNBC, HER2+) and BRCA status. Uptake ratios (SUVmax tumor/SUV max opposite breast) ranged from 1.2-10.5 with a median 4.0. Ex vivo[125I]-KX1 autoradiography was performed on a subset of untreated primary tumors (n=5) and compared with IHC staining for PARP-1 on sequential sections. This revealed a close spatial correspondence between elevated PARP-1 expression by IHC and regions of elevated [125I]-KX1 binding radiographically. There was also a strong positive correlation between in vivo [18F]-FTT uptake and ex vivo quantitative [125I]-KX1 autoradiography (r=0.78). Genomic analysis of HRD in all tumors is pending and will be reported.

Conclusion: Initial analyses support the ability of [18F]-FTT to visualize and measure PARP-1 expression in breast cancer. This is the first step toward developing an imaging companion diagnostic to help guide PARP inhibitor treatment in breast cancer. Ongoing studies are expanding upon these results, testing the extent to which expression of PARP-1 by [18F]-FTT can predict response to PARP inhibitors and measure target engagement during therapy.

Citation Format: McDonald ES, Carlin S, Maxwell KN, Nayak A, Doot RK, Pantel AR, Farwell MD, Pryma DA, Clark AS, Shah P, DeMichele AM, Ziober A, Schubert EK, Palmer K, Lee HS, Matro J, de la Cruz L, Tchou J, Anderson DN, Feldman MD, Sheffer RE, Knollman H, Schnall MD, Makvandi M, Domchek S, Hubbard RA, Mach RH, Mankoff DA. PET imaging of PARP-1 expression in breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD4-07.

Abstract OT2-06-03: METAMORPH: METAstatic markers of recurrent tumor PHenotype for breast cancer

Up to 30% of patients diagnosed with breast cancer will develop recurrent disease within their lifetime, and currently this form of the disease is incurable. There are unmet needs to better understand underlying metastatic biology, identify new therapeutic targets and develop better methods for monitoring changes in disease, both to monitor response and elucidate resistance mechanisms. To address these needs, the METAMORPH Study encompasses a comprehensive approach that combines serial molecular tissue profiling at the RNA and DNA level with circulating markers (DTCs, CTCs, plasma tumor DNA), and ongoing assessment of therapeutic response.

METAMORPH is a prospective cohort study of women with suspected or confirmed recurrent breast cancer and accessible tumor by standard clinical biopsy, who are enrolled at the University of Pennsylvania prior to starting a new therapy for recurrent metastatic disease. The aims of this trial are to (1) evaluate the mechanisms through which recurrent breast cancer are genetically distinct from the primary tumor, (2) evaluate the circulating tumor biomarker trajectory of recurrent disease, (3) elucidate “escape pathways” of progressing tumors that emerge during the selective pressure of therapy, and (4) explore clinical utility of tumor and blood testing. The study protocol integrates research aims into clinical care, including a standardized approach to disease assessment and biopsy, pathologic confirmation of histology and receptor subtype, panel-based CLIA-approved genomic profiling, collection of research specimens, and standardized reporting of results, which are returned to patients and physicians. Patients are followed for treatment and outcome, and serial samples are collected at progression. A companion protocol, COMET, provides education about genomic testing and assesses patient understanding and impact of results. To date, 155 patients have enrolled, 142 (92%) have been biopsied, 120 (77%) have had sufficient DNA for molecular profiling and 109 (70%) have had genomic panel testing. Accrual is ongoing, with an initial target of 300 patients. Multiple sites within the UPHS Health System are enrolling. Contact information: angela.demichele@uphs.upenn.edu.

Key words: Metastatic disease, tumor profiling.

Citation Format: DeMichele A, Soucier-Ernst DJ, Clark C, Shih N, Stavropoulos W, Maxwell KN, Feldman M, Lierbamen D, Morrissette JJD, Paul MR, Pan T-C, Wang J, Belka GK, Chen Y, Yee S, Carpenter E, Fox K, Matro J, Clark A, Shah P, Domchek S, Bradbury A, Chodosh L. METAMORPH: METAstatic markers of recurrent tumor PHenotype for 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 OT2-06-03.

Abstract PD8-04: Evolutionary history and genomic landscape of metastatic breast cancer

Background: The majority of deaths from breast cancer are due to distant metastatic disease. Despite this, few systematic genomic analyses have been performed on metastatic tumors. This results from the relative difficulty of performing biopsies on metastatic tumors, as well as the uncertainty regarding genomic determinism, according to which the majority of actionable mutations present in metastases can be discovered in the primary tumor.

Methods: “METAMORPH” is an ongoing prospective cohort study of women with suspected or confirmed recurrent breast cancer enrolled prior to starting a new therapy for recurrent metastatic disease. Biopsies of metastatic lesions were performed under radiologic guidance, and archival primary tumors were subsequently obtained. WES and sWGS were performed to determine coding mutations and aberrant copy-number in metastatic tumors from 67 patients, 33 of which were assayed with corresponding matched primary tumors.

Results: Using Bayesian approaches, we find that cancers fit one of two patterns: canonical linear evolution (whereby the metastatic tumor arises from one or more advanced primary tumor subclones) vs. branched evolution (whereby both primary and metastatic tumors develop mutations that go on to become clonal within their respective tumors after the time of dissemination). In cases where tumors show evidence of branched evolution or small subclone dissemination, we expect that a large proportion of mutations may not be represented in both the primary and corresponding metastatic tumors. Indeed, primary-metastatic tumor pairs show substantial discordance at the genomic level, sharing only ˜30% of mutations and ˜28% of copy-number alterations on average. Furthermore, we find that metastatic tumors have decreased clonal heterogeneity, suggesting a history of selection. Indeed, we find clinically relevant mutations that are present exclusively in the primary or the corresponding recurrent metastatic tumor, as well as genes that are recurrently altered in metastatic tumors, such as amplification of SRC-1, loss of genes encoding CDK inhibitors, and alterations in JAK1/2/3.Finally, compared to the primary tumors from which they arose, metastatic tumors exhibit increased frequencies of alterations in several discrete pathways, including those involving the extracellular matrix as well as PI3K/AKT/mTOR, estrogen, and HER2 signaling.

Conclusions: The low degree of genomic concordance between primary and metastatic tumors due to evolutionary distance, as well as the presence of activating and targetable mutations specifically in metastatic tumors, suggests that there is value in comprehensively characterizing metastatic tumors to inform patient treatment and identify novel targets underlying breast cancer progression.

Citation Format: Paul MR, Pan T-C, Pant D, Belka GK, Chen Y, Shih N, Lieberman D, Morrissette JJD, Soucier-Ernst D, Clark C, Stavropoulos W, Maxwell K, Feldman M, DeMichele A, Chodosh LA. Evolutionary history and genomic landscape of 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 PD8-04.

Abstract P5-10-04: Spectrum of hereditary breast and ovarian cancer gene variants in an African American cohort

Background: Few reports describe the spectrum of mutations in breast and ovarian cancer predisposition genes found specifically in African Americans. Methods: 560 women who self-identified as African American (AA) from the University of Pennsylvania and Wayne State University were included in this IRB-approved, case-control study. Cases (n=218 with a personal history of breast and/or ovarian cancer) and controls (n=342 without breast or ovarian cancer) underwent germline genetic testing using the Color Genomics 19-gene breast and ovarian cancer risk panel. The subset of AA patients diagnosed with breast cancer ≤40 (n=185) was compared to an institutional cohort of white patients with breast cancer diagnosed ≤40 (n=189). Results: Of 218 AA cases, 70 had pathogenic or likely pathogenic (P/LP) mutations (BRCA1: n=36; BRCA2: n=24; TP53: n=3; RAD51D: n=2; ATM: n=2; CHEK2: n=2 and MSH6: n=1). Forty-two of 218 patients (19%) had at least one variant of uncertain significance (VUS). Of 342 AA controls, 5 women had P mutations in 5 distinct genes: BRCA2, ATM, BRIP1, PALB2 and PMS2. 55 control patients (16%) had at least one VUS. Many of the 75 P/LP mutations (cases, 70 mutations; controls, 5 mutations) in the full AA cohort were unique variants. In the 135 patients who had BRCA1/BRCA2 sequencing prior to testing under this protocol, the Color Genomics platform identified all 56 pathogenic mutations. Among AA patients diagnosed with breast cancer ≤40 (n=185), the incidence of TP53 and ATM pathogenic mutations was similar to the white, early-onset breast cancer cohort (n=189): TP53, 1% in both cohorts; ATM = 1% in AA patients and 2% in whites. However, no patients in the AA, early-onset cohort had germline CHEK2 mutations, compared to 4% of white, early-onset breast cancer patients (p=0.007). Conclusions: Taken together, the results of this study demonstrate the importance of considering germline mutation testing in the AA population. Examination of mutations and disease phenotypes within the AA population may facilitate understanding of the clinical risk associated with variants of uncertain significance. Further comparative data between the AA and white cohorts will be presented.

Citation Format: Shah PD, Digiovanni L, Maxwell KN, Bradbury AR, Van Den Akker J, Kim S, Gil E, Simon MS, Nathanson KL, Domchek SM. Spectrum of hereditary breast and ovarian cancer gene variants in an African American cohort [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 P5-10-04.

Abstract P6-07-05: Mutational spectrum and tumor response in metastatic breast cancer

Background: While several comprehensive genomic sequencing tests are clinically available for breast cancer(BC), little is known about the spectrum of findings reported in the general population and clinical utility of findings for patients(pts). Here we report tumor sequencing from the METAMORPH study, a comprehensive genomic testing approach in pts with metastatic(met) BC.

Methods: Pts with either known or suspected BC mets consented to and clinically underwent concurrent diagnostic and research tumor biopsies(bx). FFPE specimens were profiled via Illumina TruSeq Cancer Panel next generation sequencing platform covering 212 amplicons in 47 cancer genes. Pathology, treatment and outcome data were prospectively collected and tracked. Aside from Her2-directed treatment, therapy was not mutation (mut)-matched.

Results: 64 pts enrolled between 11/2013 – 05/2015. Of these, 48 had bx successfully sequenced (75%). Of those without sequencing, 5 had negative/insufficient tissue, 2 had insufficient DNA, remainder no bx/pending. Median age of those sequenced was 56 (range 31-78); 81% Caucasian, 17% African American. 25% (12 pts) presented with de novo stage IV disease. Of those with recurrence (n=36), 83% had prior adjuvant chemotherapy; 81% hormone receptor positive(HR+) had prior endocrine therapy. Median # prior lines of therapy for met disease was 2 (IQR 0 – 8). Tumor characteristics, including mut analyses, are shown in Table 1. # muts did not differ significantly by subtype(p=0.22). Frequency of TP53 and PIK3CA hotspot muts was nearly identical to TCGA. Median # muts was 1 for pts with both de novo mets and recurrence(p=0.79). # of muts was not associated with time to recurrence(p=0.80). Excluding pts found to have TP53 mut only or ERBB2 alterations in known Her2+ disease, 42% of pts were identified as having at least one potentially actionable alteration (PIK3CA mut, AKT1 mut or EGFR amplification). Median time to treatment failure(TTF) on subsequent therapy was 4.1 months for overall group, and 4.1, 6.2, and 1.6 months for HR+/Her2-, any Her2+ and TN, respectively, adjusted for line of therapy(p=0.03). After adjustment for # lines of prior met therapy, TTF was 4.7 vs. 4.1 months for pts with any mut vs. none(p=0.89); 5.7 vs 4.1 months for PIK3CA+ vs. not (p=0.94); 3.3 vs. 6.5 months for TP53+ vs. not (p=0.03).

Conclusion: Pts with met BC have frequent and potentially actionable muts.While overall # of muts did not affect response, tumors with TP53 muts had shorter response to subsequent therapy in this cohort. Additional data are needed to determine the clinical utility of mut testing in met BC, for both standard and mut-matched therapy.

 Total (n=48)HR+/Her2- (n=28)Any HER2+ (n=7)TN (n=13)Receptor concordant with primary 100%78%77%# Mutations Median (Range)1 (0-4)1 (0-3)1 (1-2)1 (0-4)014 (29%)10 (36 %)04 (31%)118 (38%)11 (39%)4 (57%)3 (23%)213 (27%)5 (18%)3 (43%)5 (38%)3+3 (6%)2 (7%)01 (8%)Prevalent Mutations (&gt;20%)TP53 (38%), PIK3CA (35%)PIK3CA (50%), TP53 (25%)TP53 (60%), ERBB2amp (86%)TP53 (62%),PIK3CA (23%)Other Alterations (#)ATM (1), KIT (1), PDGFRA (1), PTEN(1), RB1 (1), SMAD4 (1), SMO (1), STK11 (1)AKT1 (1), ATM VUS (1), ERBB2 (1), PTEN (1), SMAD4 VUS (1), SMO VUS (1)ERBB2 (1), STK11(1)EGFR amp (2), KIT amp (1),PDGFRA amp (1), RB1 VUS (1)

Citation Format: Soucier-Ernst D, Colameco C, Troxel AB, Clark C, Shih N, Maxwell KN, Morrissette J, Lieberman D, Feldman M, Goodman N, Bradbury A, Clark A, Domchek S, Fox K, Glick J, Matro J, Nathanson K, Chodosh L, DeMichele A. Mutational spectrum and tumor response in metastatic breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-07-05.

Abstract P2-09-01: Patient reported outcomes of multiplex breast cancer susceptibility testing utilizing a tiered-binned counseling and informed consent model in BRCA1/2 negative patients

Background:The risks, benefits and utilities of multiplex panels for breast cancer susceptibility are unknown and new counseling and informed consent models are needed. We sought to obtain patient reported outcomes of multiplex testing in BRCA1/2 negative patients utilizing a novel, previously piloted tiered-binned counseling model for multiplex testing. Methods:BRCA1/2 negative participants completed pre(V1) and post-test counseling(V2) and surveys evaluating cognitive, affective and behavioral responses to a 25-gene multiplex testing panel. We used linear regressions with estimation by GEE where appropriate. Results:376 patients have been approached. To date, 124 participants(33%) have consented to the study, 21(6%) declined and 231(61%) are considering. Of 95 who have completed pre-test counseling(V1), 88(93%) elected to proceed with 25-gene panel testing and (81%) were classified as making an informed choice after tiered-binned counseling. 6/53(11%) participants received a positive result, including 1 mutation in MSH2 and 5 in moderate penetrance genes (2 ATM, 1 BARD1, 1 CHEK2, 1 PALB2). 22/53(42%) participants received a variant of unknown significance(VUS). General anxiety and perceived utility decreased significantly with pre-test counseling and after results (Table 1). Knowledge increased with pre-test counseling; cancer worry increased after receipt of multiplex results. Higher cancer worry was associated only with lower income (2.6 points/income category, p&lt;0.01). Those with a VUS had greater decreases in perceived utility compared to negative (p=0.01) or positive (p=0.003) results. To date, there are no other significant differences in knowledge, distress or uncertainty by test result. Medical management recommendations for the proband changed in 3/6 with a positive result. Cascade testing in the family was discussed as an option in 3/6 with a positive result. Conclusions:Many BRCA1/2-negative patients proceed with 25-gene cancer susceptibility testing if offered and most make informed choices utilizing a tiered-binned genetic counseling model. The tiered-binned counseling model is associated with increased knowledge, decreases in general anxiety and uncertainty after pre-test counseling and disclosure of results, but an increase in cancer worry after result disclosure. The clinical utility, long-term outcomes and differences in patient reported outcomes by test result remain unknown.

Table 1 Baseline, Mean(SD)After V1, Mean(SD)After V2, Mean(SD) N=75ˆ;N=49ˆˆN=75ˆ;N=49ˆˆN=49ˆˆGeneral Anxiety (range 0-21)6.4(3.9)*;6.9(3.9)**6.0(4.3)*;6.6(4.2)**5.8(4.5)**General Depression (range 0-212.8(2.9);3.1(3.2)3.0(3.5);3.1(3.6)3.0(3.7)State Anxiety (range 20-80)35.5(11.2);36.6(11.9)35.5(11.8);36.8(11.9)36.1(12.2)Cancer Worry (range 0-75)18.2(13.5);20.1(13.8)**16.7(12.5);17.2(11.9)**21.0(13.9)**Knowledge (range 17-82)65.7(5.0)**;66.5(5.0)**68.0(5.7)**;68.4(5.6)**67.3(4.9)**Uncertainty (range 0-15)5.8(3.9);6.2(4.3)5.6(3.7);5.4(3.2)5.6(3.5)Perceived Utility (range 24-120)75.2(14.0)*;75.9(14.0)**73.0(14.1)*;74.1(13.4)**68.4(16.9)***p≤0.05 **p≤0.01. ˆcompleted V1. ˆˆcompleted V1 & V2. To date, 53 have received results and 49 have completed post-disclosure surveys.

Citation Format: Bradbury AR, Patrick-Miller L, Egleston BE, Maxwell KN, Brandt A, Brower J, DiGiovanni L, Long JM, Powers J, Stopfer J, Nathanson KL, Domchek SM. Patient reported outcomes of multiplex breast cancer susceptibility testing utilizing a tiered-binned counseling and informed consent model in BRCA1/2 negative patients. [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 P2-09-01.

Hydrophobic trichome layers and epicuticular wax powders in Bromeliaceae

The distinctive foliar trichome of Bromeliaceae has promoted the evolution of an epiphytic habit in certain taxa by allowing the shoot to assume a significant role in the uptake of water and mineral nutrients. Despite the profound ecophysiological and taxonomic importance of this epidermal structure, the functions of nonabsorbent trichomes in remaining Bromeliaceae are not fully understood. The hypothesis that light reflection from these trichome layers provides photoprotection was not supported by spectroradiometry and fluorimetry in the present study; the mean reflectance of visible light from trichome layers did not exceed 6.4% on the adaxial surfaces of species representing a range of ecophysiological types nor was significant photoprotection provided by their presence. Several reports suggesting water repellency in some terrestrial Bromeliaceae were investigated. Scanning electron microscopy (SEM) and a new technique-fluorographic dimensional imaging (FDI)-were used to assess the interaction between aqueous droplets and the leaf surfaces of 86 species from 25 genera. In the majority of cases a dense layer of overlapping, stellate or peltate trichomes held water off the leaf epidermis proper. In the case of hydrophobic tank-forming tillandsioideae, a powdery epicuticular wax layer provided water repellency. The irregular architecture of these indumenta resulted in relatively little contact with water droplets. Most mesic terrestrial Pitcairnioideae examined either possessed glabrous leaf blades or hydrophobic layers of confluent trichomes on the abaxial surface. Thus, the present study indicates that an important ancestral function of the foliar trichome in Bromeliaceae was water repellency. The ecophysiological consequences of hydrophobia are discussed.

Importance of specific nucleotides in the folding of the natural form of the hairpin ribozyme

The hairpin ribozyme in its natural context consists of two loops in RNA duplexes that are connected as arms of a four-way helical junction. Magnesium ions induce folding into the active conformation in which the two loops are in proximity. In this study, we have investigated nucleotides that are important to this folding process. We have analyzed the folding in terms of the cooperativity and apparent affinity for magnesium ions as a function of changes in base sequence and functional groups, using fluorescence resonance energy transfer. Our results suggest that the interaction between the loops is the sum of a number of component interactions. Some sequence variants such as A10U, G+1A, and C25U exhibit loss of cooperativity and reduced affinity of apparent magnesium ion binding. These variants are also very impaired in ribozyme cleavage activity. Nucleotides A10, G+1, and C25 thus appear to be essential in creating the conformational environment necessary for ion binding. The double variant G+1A/C25U exhibits a marked recovery of both folding and catalytic activity compared to either individual variant, consistent with the proposal of a triple-base interaction among A9, G+1, and C25 [Pinard, R., Lambert, D., Walter, N. G., Heckman, J. E., Major, F., and Burke, J. M. (1999) Biochemistry 38, 16035-16039]. However, substitution of A9 leads to relatively small changes in folding properties and cleavage activity, and the double variant G+1DAP/C25U (DAP is 2,6-diaminopurine), which could form an isosteric triple-base interaction, exhibits folding and cleavage activities that are both very impaired compared to those of the natural sequence. Our results indicate an important role for a Watson--Crick base pair between G+1 and C25; this may be buttressed by an interaction with A9, but the loss of this has less significant consequences for folding. 2'-Deoxyribose substitution leads to folding with reduced magnesium ion affinity in the following order: unmodified RNA > dA9 > dA10 > dC25 approximately dA10 plus dC25. The results are interpreted in terms of an interaction between the ribose ring of C25 and the ribose and base of A10, in agreement with the proposal of Ryder and Strobel [Ryder, S. P., and Strobel, S. A. (1999) J. Mol. Biol. 291, 295-311]. In general, there is a correlation between the ability to undergo ion-induced folding and the rate of ribozyme cleavage. An exception to this is provided by G8, for which substitution with uridine leads to severe impairment of cleavage but folding characteristics that are virtually unaltered from those of the natural species. This is consistent with a direct role for the nucleobase of G8 in the chemistry of cleavage.

The folding of the hairpin ribozyme: dependence on the loops and the junction

In its natural context, the hairpin ribozyme is constructed around a four-way helical junction. This presents the two loops that interact to form the active site on adjacent arms, requiring rotation into an antiparallel structure to bring them into proximity. In the present study we have compared the folding of this form of the ribozyme and subspecies lacking either the loops or the helical junction using fluorescence resonance energy transfer. The complete ribozyme as a four-way junction folds into an antiparallel structure by the cooperative binding of magnesium ions, requiring 20-40 microM for half-maximal extent of folding ([Mg2+]1/2) and a Hill coefficient n = 2. The isolated junction (lacking the loops) also folds into a corresponding antiparallel structure, but does so noncooperatively (n = 1) at a higher magnesium ion concentration ([Mg2+]1/2 = 3 mM). Introduction of a G + 1A mutation into loop A of the ribozyme results in a species with very similar folding to the simple junction, and complete loss of ribozyme activity. Removal of the junction from the ribozyme, replacing it either with a strand break (serving as a hinge) or a GC5 bulge, results in greatly impaired folding, with [Mg2+]1/2 > 20 mM. The results indicate that the natural form of the ribozyme undergoes ion-induced folding by the cooperative formation of an antiparallel junction and loop-loop interaction to generate the active form of the ribozyme. The four-way junction thus provides a scaffold in the natural RNA that facilitates the folding of the ribozyme into the active form.

The spd-2 gene is required for polarization of the anteroposterior axis and formation of the sperm asters in the Caenorhabditis elegans zygote

In the Caenorhabditis elegans zygote, polarization of the anteroposterior (AP) axis occurs during a brief period of reorganization that follows fertilization and results in the establishment of discrete cytoplasmic and cortical domains. In the cytoplasm, germ-line or P granules are circulated by an actomyosin-driven fountain flow of cytoplasm and localize to the posterior, while in the cortex, two proteins required for AP polarity, PAR-2 and PAR-3, localize to the posterior and the anterior, respectively. The identity of the positional cue that determines AP axis orientation is not known, although it has been postulated to be a component of the sperm pronucleus/centrosome complex (SPCC) as the position of the SPCC correlates with the orientation of the AP axis and the direction of the fountain flows. Here, we show that mutations in the spd-2 gene disrupt polarization of the AP axis. In mutant zygotes, the fountain flow of cytoplasm and associated asymmetric cortical contractions are absent, P granules do not localize, and cortical PAR-3 does not become asymmetrically distributed. Interestingly, cortical PAR-2 localizes randomly to either or both poles. The random positioning of PAR-2 requires PAR-3 and indicates that a spd-2-dependent mechanism normally modulates PAR-2/PAR-3 interactions to correctly position PAR-2 at the posterior. spd-2 mutations also disrupt formation of the SPCC by delaying and attenuating the formation of sperm asters until after the period of reorganization, suggesting that spd-2 mutations disrupt formation of the positional cue. Our results also indicate that sperm asters are not essential for pronuclear migration but are required for rapid female pronuclear movement and premitotic positioning of the pronuclei.

Chlorophyll fluorescence--a practical guide

Chlorophyll fluorescence analysis has become one of the most powerful and widely used techniques available to plant physiologists and ecophysiologists. This review aims to provide an introduction for the novice into the methodology and applications of chlorophyll fluorescence. After a brief introduction into the theoretical background of the technique, the methodology and some of the technical pitfalls that can be encountered are explained. A selection of examples is then used to illustrate the types of information that fluorescence can provide.

Chlorophyll fluorescence--a practical guide

Chlorophyll fluorescence analysis has become one of the most powerful and widely used techniques available to plant physiologists and ecophysiologists. This review aims to provide an introduction for the novice into the methodology and applications of chlorophyll fluorescence. After a brief introduction into the theoretical background of the technique, the methodology and some of the technical pitfalls that can be encountered are explained. A selection of examples is then used to illustrate the types of information that fluorescence can provide.

Glucose uptake increases relative to oxygen consumption during short-term hibernation

BACKGROUND

Although glucose uptake is increased in chronically hypoperfused, viable myocardium, the dynamic changes in glucose uptake relative to oxygen consumption in "short-term" models of hibernation have not been fully explored.

METHODS

14 anesthetized swine were instrumented with an hydraulic occluder and flow probe on the proximal LAD artery. Blood flow was reduced approximately 30% for 1 hour. Myocardial blood flow and uptake of oxygen, free fatty acids, glucose and lactate were determined in the LAD region at baseline and at 10, 30, and 60 minutes of ischemia. Transmural biopsies for ATP and creatine phosphate (CP) were obtained in the LAD region prior to and at 15 and 45 minutes of ischemia. In 5 animals, glycogen was assayed at baseline and at the end of 60 minutes of ischemia.

RESULTS

In the LAD region, myocardial oxygen consumption was reduced from 2.06 +/- 0.16 micromol/min/gram to 1.46 +/- 0.13 micromol/min/gram (P < 0.05). By 15 minutes of ischemia, transmural creatine phosphate fell from 7.48 +/- 0.76 micromol/g-wet weight at baseline to 6.19 +/- 0.32 micromol/g-wet weight (P < 0.05) but normalized by 45 minutes of ischemia (7.39 +/- 0.56 micromol/g-wet weight; NS). Between 10 and 60 minutes of constant flow reduction, glucose uptake as a percentage of MVO2 increased from 3 +/- 2% to 10 +/- 2% (P < 0.05) while lactate uptake increased from -9 +/- 9% to -1 +/- 2% (P < 0.05). Glycogen decreased from 27.8 +/- 3.7 at baseline to 16.9 +/- 1.2 micromol/g-wet weight at end-ischemia.

CONCLUSIONS

In this model of short-term hibernation, glucose and lactate uptake increase relative to oxygen consumption during sustained ischemia, and temporally coincide with the recovery of bioenergetics. The findings are consistent with the notion that glycolytically derived ATP is important for the maintainance of energy supply during sustained ischemia.

Functional role of ionic regulation of Na+/Ca2+ exchange assessed in transgenic mouse hearts

Na+/Ca2+ exchange is the primary mechanism mediating Ca2+ efflux from cardiac myocytes during diastole and, thus, can prominently influence contractile force. In addition to transporting Na+ and Ca2+, the exchanger is also regulated by these ions. Although structure-function studies have identified protein regions of the exchanger subserving these regulatory processes, their physiological importance is unknown. In this study, we examined the electrophysiological and mechanical consequences of cardiospecific overexpression of the canine cardiac exchanger NCX1.1 and a deletion mutant of NCX1.1 (Delta680-685), devoid of intracellular Na+ (Na+i)- and Ca2+ (Ca2+i)- dependent regulatory properties, in transgenic mice. Using the giant excised patch-clamp technique, normal ionic regulation was observed in membrane patches from cardiomyocytes isolated from control and transgenic mice overexpressing NCX1.1. In contrast, ionic regulation was nearly abolished in mice overexpressing Delta680-685, indicating that the native regulatory processes could be overwhelmed by expression of the transgene. To address the physiological consequences of ionic regulation of the Na+/Ca2+ exchanger, we examined postrest force development in papillary muscles from NCX1.1 and Delta680-685 transgenic mice. Postrest potentiation was found to be substantially greater in Delta680-685 than in NCX1.1 transgenic mice, supporting the notion that ionic regulation of Na+/Ca2+ exchange plays a significant functional role in cardiac contractile properties.

Experiences of hospital care and treatment-seeking behavior for pain from sickle cell disease: qualitative study

OBJECTIVE

To investigate how sociocultural factors influence the management of pain from sickle cell disease by comparing the experiences of those who usually manage their pain at home with the experiences of those who are more frequently admitted to hospital for management of their pain.

DESIGN

Qualitative analysis of semistructured individual interviews and focus group discussions.

PARTICIPANTS

57 participants with genotype SS or S/beta-thal (44 participants) or SC (9 participants); the status of 4 participants was unknown. 40 participants took part in focus groups, 6 took part in both focus groups and interviews, and 9 were interviewed only. Participants were allocated to focus groups according to ethnic origin, sex, and the number of times that they had been admitted to the hospital for the management of painful crises during the previous year.

RESULTS

The relation between patients with sickle cell disease and hospital services is one of several major, nonclinical dimensions that shape experiences of pain management and behavior for seeking health care. Participants' experiences of hospital care show a range of interrelated themes that are common to most participants across variables of sex, ethnicity, and which hospital was attended. Themes identified included the mistrust of patients with sickle cell disease, stigmatization, excessive control (including both overtreatment and undertreatment of pain) and neglect. Individuals responded to the challenge of negotiating care with various strategies. Patients with sickle cell disease who are frequently admitted to hospital may try to develop long-term relationships with their caregivers, become passive or aggressive in their interactions with health professionals, or regularly attend different hospitals. Those who usually manage their pain at home expressed a strong sense of responsibility for the management of their pain and advocated self-education, assertiveness, and resistance as strategies toward hospital services.

CONCLUSIONS

The organization and delivery of management for the pain of a sickle cell crisis discourages self-reliance and encourages hospital dependence. Models of care should recognize the chronic nature of sickle cell disorders and give priority to patients' involvement in their care.

Chloroplast acclimation in leaves of Guzmania monostachia in response to high light

Acclimation of leaves to high light (HL; 650 micromol m(-2) s(-1)) was investigated in the long-lived epiphytic bromeliad Guzmania monostachia and compared with plants maintained under low light (LL; 50 micromol m(-2) s(-1)). Despite a 60% decrease in total chlorophyll in HL-grown plants, the chlorophyll a/b ratio remained stable. Additionally, chloroplasts from HL-grown plants had a much lower thylakoid content and reduced granal stacking. Immunofluorescent labeling techniques were used to quantify the level of photosynthetic polypeptides. HL-grown plants had 30% to 40% of the content observed in LL-grown plants for the light-harvesting complex associated with photosystems I and II, the 33-kD photosystem II polypeptide, and Rubisco. These results were verified using conventional biochemical techniques, which revealed a comparable 60% decrease in Rubisco and total soluble protein. When expressed on a chlorophyll basis, the amount of protein and Rubisco was constant for HL- and LL-grown plants. Acclimation to HL involves a tightly coordinated adjustment of photosynthesis, indicating a highly regulated decrease in the number of photosynthetic units manifested at the level of the content of light-harvesting and electron transport components, the amount of Rubisco, and the induction of Crassulacean acid metabolism. This response occurs in mature leaves and may represent a strategy that is optimal for the resource-limited epiphytic niche.

Risperidone-induced hepatotoxicity in children and adolescents? A chart review study

Risperidone is an atypical antipsychotic drug that has been used in the treatment of numerous psychiatric disorders in children and adolescents. The question of whether risperidone-induced weight gain is associated with steatohepatitis has recently been raised. The purpose of this chart review was to ascertain: (1) the rate of liver dysfunction observed during risperidone treatment in children and adolescents; and (2) the clinical factors associated with liver dysfunction. For purposes of this chart review study, abnormal liver function was defined by serum transaminase or bilirubin values falling outside the normal laboratory ranges. Chart reviews were completed on 38 youths with ages ranging from 5-17 years with a variety of psychiatric diagnoses. The mean length of risperidone treatment was 15.2 months at a mean dose of 2.5 mg/day. It was found that 37 of the 38 youths treated with risperidone had no liver enzyme abnormalities at the end of study. One subject had an alanine aminotransferase (ALT) level of 46 U/L which was 7 U/L above the upper limit of normal for this laboratory test. This isolated value was not considered clinically significant. These data were noted in spite of weight gain and the use of numerous concomitant psychotropic medications. These findings suggest that risperidone in short term treatment does not commonly lead to evidence of abnormal liver function at therapeutic doses in children and adolescents. Larger-scale, prospective studies are needed in order to confirm these findings.

Experiences of hospital care and treatment seeking for pain from sickle cell disease: qualitative study

OBJECTIVE

To investigate how sociocultural factors influence management of pain from sickle cell disease by comparing the experiences of those who usually manage their pain at home with those who are more frequently admitted to hospital for management of their pain.

DESIGN

Qualitative analysis of semistructured individual interviews and focus group discussions.

PARTICIPANTS

57 participants with genotype SS or S/beta-thal (44 subjects) or SC (9) (4 were unknown). 40 participants took part in focus groups, six took part in both focus groups and interviews, and nine were interviewed only. Participants were allocated to focus groups according to number of hospital admissions for painful crisis management during the previous year, ethnic origin, and sex.

RESULTS

The relation between patients with sickle cell disease and hospital services is one of several major non-clinical dimensions shaping experiences of pain management and behaviour for seeking health care. Experiences of hospital care show a range of interrelated themes, which are common to most participants across variables of sex, ethnicity, and hospital attended: mistrust of patients with sickle cell disease; stigmatisation; excessive control (including both over- and undertreatment of pain); and neglect. Individuals respond to the challenge of negotiating care with various strategies. Patients with sickle cell disease who are frequently admitted to hospital may try to develop long term relationships with their carers, may become passive or aggressive in their interactions with health professionals, or may regularly attend different hospitals. Those individuals who usually manage their pain at home express a strong sense of self responsibility for their management of pain and advocate self education, assertiveness, and resistance as strategies towards hospital services.

CONCLUSIONS

The current organisation and delivery of management of pain for sickle cell crisis discourage self reliance and encourage hospital dependence. Models of care should recognise the chronic nature of sickle cell disorders and prioritise patients' involvement in their care.

Structure-function analysis of CALX1.1, a Na+-Ca2+ exchanger from Drosophila. Mutagenesis of ionic regulatory sites

Cytoplasmic Na+ and Ca2+ regulate the activity of Na+-Ca2+ exchange proteins, in addition to serving as the transported ions, and protein regions involved in these processes have been identified for the canine cardiac Na+-Ca2+ exchanger, NCX1.1. Although protein regions associated with Na+i- and Ca2+i-dependent regulation are highly conserved among cloned Na+-Ca2+ exchangers, it is unknown whether or not the structure-function relationships characteristic of NCX1.1 apply to any other exchangers. Therefore, we studied structure-function relationships in a Na+-Ca2+ exchanger from Drosophila, CALX1.1, which is unique among characterized members of this family of proteins in that microM levels of Ca2+i inhibit exchange current. Wild-type and mutant CALX1.1 exchangers were expressed in Xenopus oocytes and characterized electrophysiologically using the giant excised patch technique. Mutations within the putative regulatory Ca2+i binding site of CALX1. 1, like corresponding alterations in NCX1.1, led to reduced ability (i.e. D516V and D550I) or inability (i.e. G555P) of Ca2+i to inhibit Na+-Ca2+ exchange activity. Similarly, mutations within the putative XIP region of CALX1.1, as in NCX1.1, led to two distinct phenotypes: acceleration (i.e. K306Q) and elimination (i.e. Delta310-313) of Na+i-dependent inactivation. These results indicate that the respective regulatory roles of the Ca2+i binding site and XIP region are conserved between CALX1.1 and NCX1.1, despite opposite responses to Ca2+i. We extended these findings using chimeric constructs of CALX1.1 and NCX1.1 to determine whether or not functional interconversion of Ca2+i regulatory phenotypes was feasible. With one chimera (i.e. CALX:NCX:CALX), substitution of a 193-amino acid segment, from the large intracellular loop of NCX1.1, for the corresponding 177-amino acid segment of CALX1.1 led to an exchanger that was stimulated by Ca2+i. This result indicates that the regulatory Ca2+i binding site of NCX1.1 retains function in a CALX1. 1 parent transporter and that the substituted segment contains some of the amino acid sequence(s) required for transduction of the Ca2+i binding signal.

Biology and function of the reversible sulfation pathway catalysed by human sulfotransferases and sulfatases

Sulfation and sulfate conjugate hydrolysis play an important role in metabolism, and are catalysed by members of the sulfotransferase and sulfatase enzyme super-families. In general, sulfation is a deactivating, detoxication pathway, but for some chemicals the sulfate conjugates are much more reactive than the parent compound. The range of compounds which are sulfated is enormous, yet we still understand relatively little of the function of this pathway. This review summarises current knowledge of the sulfation system and the enzymes involved, and illustrates how heterologous expression of sulfotransferases (SULTs) and sulfatases is aiding our appreciation of the properties of these important proteins. The role of sulfation in the bioactivation of procarcinogens and promutagens is discussed, and new data on the inhibition of the sulfotransferase(s) involved by common dietary components such as tea and coffee are presented. The genetic and environmental factors which are known to influence the activity and expression of human SULTs and sulfatases are also reviewed.

Laser-cured fibrinogen glue to repair bleb leaks in rabbits

OBJECTIVE

To determine whether laser-cured fibrinogen glue can close bleb leaks in rabbits.

METHODS

Full-thickness filtration surgery with intraoperative mitomycin and a sutured limbus-based conjunctival flap was performed in 1 eye each of 19 New Zealand albino rabbits. On the second postoperative day, a 2- to 3-mm hole was made in the bleb. In 9 rabbits, the hole was glued using fibrinogen glue with indocyanine green dye added. The glue was "cured" with a diode laser. Eyes that had been glued and developed a subsequent leak had the glue reapplied on the day the leak was detected.

RESULTS

The glue remained on the conjunctiva for an average (mean+/-SD) of 1.9+/-1.8 days (range, 0-5 days). The last day of bleb leak for the rabbits with glued eyes was 1.6+/-2.4 days; for the control rabbits, it was 8.0+/-4.4 days (P=.001, Mann-Whitney U test).

CONCLUSION

Laser-cured fibrinogen glue is effective in closing bleb leaks in rabbits.

Endoscopic creation of reflux in the pig

Vesicoureteral reflux (VUR) in the animal model for experimental purposes can be created either by open transvesical or endoscopic techniques. The concept of reflux creation is the same for both techniques: incision of the roof of the intramural portion of the ureter at the 12 o'clock position. The open method has the disadvantages of requiring a cystotomy and a lengthy healing period prior to initiating a study, thereby incurring additional expense and the problem of introducing several confounding factors. The open method is unreliable because of the resolution of reflux over time. Herein, we present a simple transurethral endoscopic technique for creating VUR in pigs. This technique was successful in producing persistent Grade II or III reflux in 94% of the incised ureters.

Not a 'proper' solution? The gap between professional guidelines and users' views about the safety of using emergency contraception

OBJECTIVES

As a form of contraception which is used after sex, emergency contraception occupies a singular place in the birth control repertoire. The relatively high UK incidence of pregnancy terminations and of teenage pregnancy, combined with the recognition that much early sex remains unplanned and unprotected, has led to calls for better access to emergency contraceptive methods. In this study a combination of self-completion questionnaires and semi-structured interviews was used to explore views of emergency contraception among women who were using the method.

METHODS

Five hundred and ten women attending two family planning clinics in Oxford and London completed a questionnaire in the waiting room and 53 women who were attending for emergency contraception took part in semi-structured interviews.

RESULTS

The view, presented in recently published UK guidelines, that emergency contraception is a reliable method and not dangerous to repeat, was not shared by the respondents. The rationale for and sources of women's concerns about the strength of the dose of hormonal emergency contraception and the nature of side-effects are explored.

Cytokine expression in otitis media with effusion. Tumor necrosis factor soluble receptor

BACKGROUND

A variety of cytokines, such as interleukin 1 and tumor necrosis factor (TNF), appear to play a key role in the initiation and maintenance of the inflammatory response in a variety of diseases, including chronic otitis media with effusion (COME). Recently, cytokine inhibitors have been isolated and are presumed to regulate the proinflammatory effects of these cytokines. This has lead us to hypothesize that the chronic inflammation seen in COME is the result of an imbalance in the ratio of proinflammatory cytokines and inhibitors that favors the proinflammatory cytokines.

DESIGN

Middle ear effusions were evaluated for the cytokine TNF-alpha and the inhibitor TNF soluble receptor (TNFsolR) using a combination of enzyme-linked immunosorbent assays and radioactive immunoassays. We determined the presence and quantified the amounts of TNF-alpha and TNFsolR and correlated this result with clinical parameters in patients with COME.

SETTING

University hospital.

PATIENTS

To test this hypothesis, 35 middle ear effusions were obtained from 29 children aged 2 to 102 months (mean, 39.6 months) undergoing tympanostomy tube insertion for COME.

OUTCOME

Children were followed up for at least 12 months postoperatively and the number of subsequent episodes of otitis media correlated with cytokine levels.

RESULTS

The TNF-alpha and TNFsolR were present in 83% and 91% of effusions, respectively. The TNF-alpha mean (+/-SEM) cytokine values were 110.6 +/- 32.1 pg/mg of total protein, and 12886 +/- 3108 pg/mg total protein for TNFsolR. Analysis of correlations in a univariate model revealed a statistically significant relationship for TNF-alpha correlated with TNFsolR (R2 = 0.463; P < .001). The TNF-alpha levels were significantly lower for children with multiple tube insertions (P = .02). Higher levels of TNF-alpha were noted in those children who subsequently developed episodes of otitis media after tube placement (P = .02). The ratio of TNF-alpha to TNFsolR, the mean (+/-SEM) inhibitor index was 430 +/- 220 U.

CONCLUSIONS

Our data support the hypothesis that cytokines and their inhibitors are present in a large number of middle ear effusions and in part are likely important in the regulation of inflammatory processes in COME.

High-dose pyridoxine and magnesium administration in children with autistic disorder: an absence of salutary effects in a double-blind, placebo-controlled study

Several reports have described salutary effects such as decreased physical aggression and improved social responsiveness being associated with the administration of high doses of pyridoxine and magnesium (HDPM) in open-labeled and controlled studies of patients with autism. Despite this fact, this intervention remains controversial. A 10-week double-blind, placebo-controlled trial was undertaken to examine both the efficacy and safety of HDPM in autism. Twelve patients were enrolled, and 10 patients (mean age 6 years 3 months) were able to complete the study. HDPM at an average dose of 638.9 mg of pyridoxine and 216.3 mg of magnesium oxide was ineffective in ameliorating autistic behaviors as assessed by the Children's Psychiatric Rating Scale (CPRS), the Clinical Global Impression Scale, and the NIMH Global Obsessive Compulsive Scale. Furthermore, no clinically significant side effects were noted during HDPM administration. A trend for a transient change on the CPRS was found that was possibly due to a placebo response. This study raises doubts about the clinical effectiveness of HDPM in autistic disorder.

The effect of changing the total parenteral nutrition order form on resident physician ordering behavior

The quality assurance process at Scott and White Hospital, Temple, Texas, identified a marked variation in total parenteral nutrition (TPN) prescriptions compared with recommendations by the Nutrition Support Service (NSS). A TPN order form with additive guidelines was designed to assist physicians in ordering TPN specific to patient needs. The effect of the change was assessed by comparing 50 TPN patients using the old form (1990) with 50 patients for whom the new form (1992) was used. The groups demonstrated no difference in demographics, mortality, length of stay, or biochemical parameters and were reflective of all TPN patients treated (1990, n = 280; 1992, n = 392). A significant decrease was noted in overfeeding of kilocalories when resident orders were compared with NSS recommendations (125% +/- 24% versus 110% +/- 29%, p = .017; and amino acids (120% +/- 32% versus 105% +/- 29%, p = .071, mean +/- SD). This resulted in a decrease of 8% in the cost of delivering a patient-day of TPN. We conclude that changing the TPN order form to a teaching vehicle results in decreased overfeeding and costs.

An open clinical trial of risperidone monotherapy in young children with autistic disorder

Autistic disorder (AD) may be associated with dysfunctional behaviors which significantly interfere with a child's functioning. Risperidone has been described as having salutary effects as an adjunctive pharmacotherapy in adult and pediatric patients with AD. The purpose of this 8-week, open-label study was to examine the effectiveness and tolerability of risperidone monotherapy in young patients with AD. Doses of risperidone were to be started at 0.25 mg qhs and were titrated to maximize clinical efficacy. Six patients (ages 5 to 9 years) were enrolled in this protocol, and all completed it. After 8 weeks of treatment, with a mean risperidone dose of 1.1 mg, improvement in symptomatology was demonstrated by reduced scores on both the Children's Psychiatric Rating Scale (p < .005) and the Clinical Global Impressions Scale (p < .001). The most common side effect were weight gain and sedation. This study provides preliminary evidence that risperidone monotherapy may be safe and effective in ameliorating dysfunctional behaviors in children with AD.

Murine model of otitis media with effusion: immunohistochemical demonstration of IL-1 alpha antigen expression

Recent studies have suggested that cytokines likely play a central role in the formation and maintenance of otitis media with effusion (OME). Currently, there is no immunologically defined animal model for the study of cytokines as they contribute to the formation of OME. In the present study, a murine model of OME, using eustachian tube blockage via an external surgical approach, was developed. The murine model temporal bone histology appears to mimic the histology found in chronic otitis media with effusion in humans. Additionally, using this murine model, interleukin-1 alpha (IL-1 alpha) expression was detected in the middle ear using standard immunohistochemical techniques. IL-1 alpha seemed localized to the epithelial lining of the middle ear as well as 5% to 10% of inflammatory cells. This model should provide the necessary tool to further study the immunologic aspects of OME.

Effects of weight training on the emotional well-being and body image of females: predictors of greatest benefit

BACKGROUND

This study was conducted to determine the extent to which participation in a weight training intervention was associated with changes in the emotional well-being and body image of females compared to non-weight trainers. An ancillary objective was to study the extent to which psychological, physical, and demographic factors accounted for changes in emotional well-being and body image.

METHODS

The experimental group consisted of 60 females, and a comparison group was comprised of 92 females. Experimental subjects participated in a 15-week, two-day-per-week weight training intervention, while subjects in the comparison group did not participate in any weight training activities. Subjects were pre- and posttested on the General Well-Being Schedule and the Body Cathexis Scale. Experimental subjects were also tested in muscular strength and three skinfold measurements.

RESULTS

With pretest scores controlled, the weight trainers had significantly higher General Well-Being and Body Cathexis posttest scores than the comparison group. Weight trainers also showed significant increases in muscular strength, and significant decreases in skinfold thickness. Four variables predicted 38.8% of the variance of those who improved most in General Well-Being: lower pretest General Well-Being, lower parental income, greater loss of body weight, and lower posttest skinfold. Five variables predicted 61.5% of the variance of those women who improved most in Body Cathexis: lower pretest Body Cathexis, greater body weight at the outset, shorter in height, less involvement in non-weight training exercise, and lower posttest skinfold.

DISCUSSION

(ABSTRACT TRUNCATED AT 250 WORDS)

Beta-VLDL increases endothelial cell plasma membrane cholesterol

In this study, the distribution of free cholesterol in cholesterol-loaded endothelial cells was examined. For these studies, cell fractionation methods were used to assess marker enzyme activity and cholesterol distribution. Treatment of rabbit aortic endothelial cells for 3 days with 50 micrograms/ml of beta-very low density lipoprotein (beta-VLDL) or malondialdehyde-low density lipoprotein (MDA-LDL) but not LDL caused a 50-100% increase in total cell unesterified cholesterol. The accumulation of free rather than esterified cholesterol in endothelial cells may be due to the ratio of hydrolysis to esterification, which we have shown in this study to be 10-fold higher in endothelial cells than in smooth muscle cells. This free cholesterol is found in the fractions enriched in plasma membrane markers and, to a lesser extent, in the Golgi-enriched fractions. The amount of cholesterol per mg of protein was increased approximately 50% in these fractions from cells treated for 3 days with 50 micrograms/ml of beta-VLDL. These increases in cholesterol content were reversible upon incubation of cells for 3 days in medium containing 15% fetal bovine serum. Alterations in several membrane functions were also observed in cholesterol-loaded cells. The activity of alkaline phosphatase, an enzyme marker for plasma membranes, was decreased by 25% and an alteration in membrane-associated microfilaments was seen with phalloidin staining. This morphological change in microfilaments was reflected in a decrease in filament ends as shown by cytochalasin binding and occurred without a change in total actin or vinculin. These microfilament changes were reversible.(ABSTRACT TRUNCATED AT 250 WORDS)

Medical students' knowledge, attitudes, and behavior concerning diet and heart disease

Demand for physician-based dietary treatment of hypercholesterolemia is increasing, but medical care providers feel that they lack the skills and confidence necessary to provide these services. Using a self-administered questionnaire, we studied the relationships among dietary knowledge, attitudes, and behaviors to identify the educational needs of entering medical students. On average, dietary behavior and background knowledge of the diet-coronary heart disease association compared favorably to national dietary recommendations and knowledge of the U.S. public. However, practical knowledge necessary for diet counseling was weak, and attitudes about the "prudent" diet were poor. More favorable attitude scores were associated with healthier eating habits, while greater knowledge was not. Our results suggest that entering medical students already have a basic understanding of the diet-heart disease link, which is covered in the curricula of most medical schools. Medical education should include more emphasis on practical dietary knowledge and improving attitudes about the prudent diet.

Stimulation of glucose analogue uptake by cerebral microvessel endothelial cells by a product released by astrocytes

Astroglial cells, both normal and neoplastic, secreted a product that stimulated glucose uptake by cerebral microvessel endothelial cells by 23% and 50%, respectively. Neither cerebral microvessel smooth muscle cells nor oligodendrocytes affected endothelial cell glucose uptake. The astrocytic product(s) did not affect glucose uptake by aortic endothelial cells. The effect on the cerebral microvessel endothelial cells increased with increasing time of exposure of the cells to the astroglial product(s), and required the constant presence of the astrocytic product to be maintained. The presence of a protein synthesis inhibitor during endothelial cell exposure to the astroglial conditioned medium blocked the stimulation of glucose uptake. Treatment of the astrocytic product with a protease destroyed its effectiveness. These results support the hypothesis that astrocytes induce the expression of at least one blood-brain barrier property by the cerebral microvasculature, and suggest that this induction may be produced by a protein released by the astrocytes.

Induction of gamma-glutamyl transpeptidase in cultured cerebral endothelial cells by a product released by astrocytes

gamma-Glutamyl transpeptidase (gamma GTP) is an enzyme found in cerebral capillary endothelial cells, the presumed site of the blood-brain barrier, but not in endothelial cells lining blood vessels in other parts of the body. Using a line of mouse cerebral microvessel endothelial cells (ME-ly cells) and a sensitive colorimetric assay to measure gamma GTP levels we demonstrated that primary cultures of mouse astrocytes and a line of rat C6 glioma cells released a soluble product(s) that induced the production of gamma GTP in cultured endothelial cells by 34% and 39%, respectively, over control levels. Cerebrovascular smooth muscle cells had no significant effect on gamma GTP levels in ME-ly cells, and the astrocyte product(s) had no effect on rabbit aortic endothelial cells. The induction of gamma GTP levels in ME-ly cells was apparent after one day of exposure to the astrocyte product(s) and increased in magnitude with increasing time of exposure of the ME-ly cells to the product(s). Removal of the product(s) from the ME-ly cells resulted in a return to control levels of gamma GTP in the ME-ly cells within 2 days. The presence of a protein synthesis inhibitor during incubation with the product(s) blocked the induction of gamma GTP in ME-ly cells, and treatment of the product(s) with 200 U/ml TPCK-trypsin destroyed its inductive properties.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of hypertension in pregnancy with methyldopa: a randomized double blind study

Twenty-five patients whose pregnancies were complicated by chronic hypertension were entered in a double-blind study and randomly allocated to treatment with methyldopa (Aldomet) or placebo. Thirteen patients were in the treatment group and 12 in the placebo group. The two groups showed no significant difference in demographic and pretreatment laboratory profiles. Methyldopa-treated patients registering in the first trimester had a significant reduction in the mean arterial pressure (MAP) during the second and third trimesters (P less than 0.025). No significant differences in birth weight (BW), ponderal index (PI) were found when results were corrected for gestational age (GA), race, and sex. The mean GA was significantly prolonged in the methyldopa-treated group by 10.3 days (P less than 0.05). The frequency of superimposed pre-eclampsia was similar in both groups (33.3% vs. 38.4%). However, 75% of the superimposed pre-eclampsia occurred antepartum in the placebo group, while 80% of the methyldopa-treated group developed superimposed pre-eclampsia intrapartum. The results of this small study suggest that the treatment of hypertension in pregnancy may reduce MAP and possibly delay the occurrence of superimposed pre-eclampsia and thus afford a prolongation of the pregnancy.

Effect of inorganic lead on some functions of the cerebral microvessel endothelium

The effect of inorganic lead on two functions of cerebral microvessel endothelium, cell division and glucose analog uptake, was investigated. Lead concentrations considered to be toxic in humans inhibited both functions in cultured endothelial cells. Both effects were dependent on the length of lead exposure and dose over the range of 10(-4) to 10(-6) M lead acetate. After 4 days of exposure there were 76% fewer cells in 10(-4) M lead-exposed cultures relative to control cultures. After 4 days of exposure to 10(-5) M lead there were 55% fewer cells, and after 10(-6) M lead exposure there were 15% fewer cells. Two days after 10(-4) M lead exposure [methyl-3H]thymidine incorporation into endothelial cells was inhibited by 71%. Incorporation was inhibited 47% by 10(-5) M lead but 10(-6) M lead did not inhibit incorporation after 2 days of exposure. Glucose analog uptake was inhibited in both contact-inhibited and log-phase cells; however, the latter were more sensitive to lead and this increased sensitivity correlated with a higher lead content in this cell population. Both the specific carrier-mediated and the nonspecific components of glucose analog uptake were inhibited by exposure of the endothelial cells to lead. A lead exposure of 40 min produced a significant effect on the uptake mechanism. In order to manifest its effects the lead had to be present in serum-containing medium, suggesting that some serum component was necessary to present the lead to the endothelial cells. These findings imply that the initial target of inorganic lead in the CNS may be the plasma membrane of the capillary endothelial cells, and that lead may act by altering the physiological function of these membranes.

Insulin stimulates DNA synthesis in cerebral microvessel endothelium and smooth muscle

Experiments were performed to test the hypothesis that insulin stimulates DNA synthesis in cerebral microvessel endothelium and smooth muscle. Cultured endothelium and smooth muscle derived from isolated mouse cerebral microvessels were exposed to insulin in serum-free medium, and [3H]-thymidine incorporation in the cells was measured. Up to 40-fold stimulation of DNA synthesis in endothelium and fourfold stimulation in smooth muscle were observed. Stimulation became maximal in both cell types at an insulin concentration of approximately 10(4) ng/ml, although an effect was observed at much lower concentrations. Similar concentrations of insulin produced a less-dramatic (approximately twofold) increase in both endothelial and smooth muscle cell numbers. This effect of insulin, observed in microvessel endothelium and smooth muscle, but not in bovine aortic endothelium, emphasizes another way in which large- and small-vessel endothelia appear to differ.

Uptake of glucose analogues into cultured cerebral microvessel endothelium

Tritiated glucose analogues 3-O-methylglucose (3-OMG) and 2-deoxyglucose (2-DG) were used to study glucose uptake properties in established lines of cultured mouse cerebral microvessel endothelium. Uptake of both analogues was similar in terms of rate and absolute amount for the first two minutes. Thereafter, intracellular accumulation of 2-DG continued at a more rapid rate because of intracellular phosphorylation of this substrate. The uptake of 3-OMG uptake was temperature-dependent, independent of Na+, and not inhibited by ouabain or 2,4-dinitrophenol. Phloretin and cytochalasin B both significantly inhibited 3-OMG uptake. Other hexoses in high concentration acted as competitive inhibitors at the endothelial cell membrane. Pre-incubation of cells with 50 mM D-glucose resulted in higher levels of 3-OMG accumulation than in control cells (counter-transport phenomenon). In contrast to findings at the blood-brain barrier in vivo, insulin was found to stimulate 3-OMG uptake. Maximal stimulation of approximately 3-fold was found at ambient insulin concentrations of 1,000 ng/ml or higher. The findings provide support at the cellular level for some components of the model of carrier-mediated glucose transport across the blood-brain barrier which has been postulated to exist in vivo. The effect of insulin is discussed in the light of new data that show stimulation of glucose analogue transport into isolated cerebral capillaries.