We isolated and characterized two human monoclonal antibodies to the envelope E2 protein of hepatitis C virus (HCV). Lymphoblastoid cell lines stably producing antibodies were obtained by immortalizing peripheral blood mononuclear cells of a patient with chronic hepatitis C using Epstein-Barr virus. Screening for antibody-positive clones was carried out by immunofluorescence with Huh7 cells expressing the E2 protein of HCV strain H (genotype 1a) isolated from the same patient. Isotype of resulting antibodies, #37 and #55, was IgG1/kappa and IgG1/lambda, respectively. Epitope mapping revealed that #37 and #55 recognize conformational epitopes spanning amino acids 429 to 652 and 508 to 607, respectively. By immunofluorescence using virus-infected Huh7.5 cells as targets both antibodies were reactive with all of the nine different HCV genotypes/subtypes tested. The antibodies showed a different pattern of immuno-staining; while #37 gave granular reactions mostly located in the periphery of the nucleus, #55 gave diffuse staining throughout the cytoplasm. Both antibodies were shown by immuno-gold electron microscopy to bind to intact viral particles. In a neutralization assay (focus-forming unit reduction using chimeric infectious HCV containing structural proteins derived from genotypes 1a, 1b, 2a, 2b, 3a, 4a, 5a, 6a, and 7a), #55 inhibited the infection of all HCV genotypes tested but genotype 7a to a lesser extent. #37 did not neutralize any of these viruses. As a broadly cross-neutralizing human antibody, #55 may be useful for passive immunotherapy of HCV infection.

Background

Family history is a risk factor for colon cancer and guidelines recommend initiating colonoscopy screening at age 40 in individuals with affected relatives. Racial differences exist in colon cancer incidence and mortality which could be related to variations in screening of increased risk individuals.

Methods

Baseline data from 41830 participants in the Southern Community Cohort Study were analyzed to determine the proportion of colonoscopy procedures in individuals with strong family histories of colon cancer, and whether differences existed based on race.

Results

In participants with multiple affected first degree relatives (FDR) or relatives diagnosed before age 50, 27.3% (95% confidence interval [CI] 23.5%–31.1%) of African-Americans reported a colonoscopy within the past 5 years compared to 43.1% (37.0%–49.2%) of white participants (p-value < 0.0001). In these individuals, African-Americans had an odds ratio of 0.51 (0.38–0.68) of having undergone recommended screening procedures compared to white participants after adjusting for age, gender, education, income, insurance status, total number of FDR, and time since last medical visit. African-Americans reporting multiple affected first degree relatives or relatives diagnosed before age 50, who had ever undergone endoscopy were less likely to report a personal history of colon polyps (OR = 0.29; 0.20–0.42) when compared to whites with similar family histories.

Conclusions

African-Americans with first-degree relatives affected with colon cancer are less likely to undergo colonoscopy screening compared to whites with affected relatives. Increased efforts need to be directed at identifying and managing underserved populations who might be at increased risk for colon cancer based on their family history.

Background:

Locally advanced inoperable pancreatic cancer (LAPC) has a poor prognosis. By increasing intensity of systemic therapy combined with an established safe chemoradiation technique, our intention was to enhance the outcomes of LAPC. In preparation for phase III evaluation, the feasibility and efficacy of our candidate regimen gemcitabine–oxaliplatin chemotherapy with sandwich 5-fluorouracil (5FU) and three-dimensional conformal radiotherapy (3DCRT) needs to be established.

Methods:

A total of 48 patients with inoperable LAPC without metastases were given gemcitabine (1000 mg m−2 d1 + d15 q28) and oxaliplatin (100 mg m−2 d2 + d16 q28) in induction (one cycle) and consolidation (three cycles), and 5FU 200 mg m−2 per day over 6 weeks during 3DCRT 54 Gy.

Results:

Median duration of sustained local control (LC) was 15.8 months, progression-free survival (PFS) was 11.0 months, and overall survival was 15.7 months. Survival rates for 1, 2, and 3 years were 70.2%, 21.3%, and 12.8%, respectively. Global quality of life did not significantly decline from baseline during treatment, which was associated with modest treatment-related toxicity.

Conclusion:

Fixed-dose gemcitabine and oxaliplatin, combined with an effective and safe regimen of 5FU and 3DCRT radiotherapy, was feasible and reasonably tolerated. The observed improved duration of LC and PFS with more intensive therapy over previous trials may be due to patient selection, but suggest that further evaluation in phase III trials is warranted.

Background.

We wished to determine if a marker of endothelial dysfunction/activation soluble vascular cell adhesion molecule (s-VCAM)—was related to functional status and mortality in community-dwelling older adults independent of the known effects of markers of inflammation and coagulation.

Methods.

Data came from the third and fourth in-person waves of the Duke Established Populations for Epidemiologic Studies of the Elderly. Participants (aged ≥ 71 years) had participated in a blood draw (N = 1,551) from which concentrations of s-VCAM, interleukin-6, and D-dimer were determined. Information was gathered in-person on demographics, health behaviors, chronic health conditions, and functional status (Katz, Rosow–Breslau, Nagi). Death was determined through the National Death Index. Multivariable regression analysis was used to examine the adjusted association of s-VCAM with functional status; Cox proportional hazards models ascertained hazard of mortality.

Results.

Controlled analyses indicated that cross-sectionally, but not longitudinally (4 years later), greater s-VCAM concentrations were associated with poorer function as measured by the Katz and Rosow–Breslau scales (p < .05 for both), independent of interleukin-6 and D-dimer. In controlled analyses, s-VCAM (p = .002), D-dimer (p = .008), and interleukin-6 (p = .01) were independently related to 4-year mortality; 1 SD increase in log concentration conferred 1.2-, 1.1-, and 1.2-fold increases in mortality, respectively. The greatest hazard of mortality was observed within the first year after measurement. s-VCAM concentrations were not predictive of 15-year mortality.

Conclusions.

Independent of inflammation and coagulation markers, endothelial dysfunction serves as a marker of, and potentially contributes causally to, poor function and death in community-dwelling older adults.

Background

Understanding the early relationship between brain tumor cells and their environment could lead to more sensitive biomarkers and new therapeutic strategies. We have been using a rodent model of neurocarcinogenesis in which all animals develop brain tumors by six months of age to establish two early landmarks in glioma development: the appearance of a nestin+ cell at thirty days of age and the appearance of cellular hyperplasia between 60 and 120 days of age. We now report an assessment of the CSF proteome to determine the changes in protein composition that occur during this period.

Materials and Methods

Nestin+ cell clusters and microtumors were assessed in 63 ethylnitrosourea-exposed rats on 30, 60, and 90 days of age. CSF was obtained from the cisterna magna from 101 exposed and control rats at 30, 60, and 90 days and then analyzed using mass spectrometry. Differentially expressed peaks were isolated and identified.

Results

Nestin+ cells were noted in all ethylnitrosourea-exposed rats assessed pathologically. Small microtumors were noted in 0%, 18%, and 67% of 30-, 60-, and 90-day old rats, respectively (p<0.05, Chi square). False Discovery Rate analysis of peak intensities showed that the number of true discoveries with p<0.05 increased markedly with increasing age. Isolation and identification of highly differentially detected proteins at 90 days of age revealed increases in albumin and a fragment of α1 macroglobulin and alterations in glutathionylated transthyretin.

Conclusions

The presence of increased albumin, fragments of cerebrospinal fluid proteins, and glutathione breakdown in temporal association with the development of cellular hyperplasia, suggests that, similar to many other systemic cancers, inflammation and oxidative stress is playing an important early role in the host’s response to brain tumor development and may be involved in affecting the early growth of brain tumor.

Murine leukemia viruses (MLV), including xenotropic-MLV-related virus (XMRV), have been controversially linked to chronic fatigue syndrome (CFS). To explore this issue in greater depth, we compiled coded replicate samples of blood from 15 subjects previously reported to be XMRV/MLV-positive (14 with CFS) and from 15 healthy donors previously determined to be negative for the viruses. These samples were distributed in a blinded fashion to nine laboratories which performed assays designed to detect XMRV/MLV nucleic acid, virus replication, and antibody. Only two laboratories reported evidence of XMRV/MLVs; however, replicate sample results showed disagreement and reactivity was similar among CFS subjects and negative controls. These results indicate that current assays do not reproducibly detect XMRV/MLV in blood samples and that blood donor screening is not warranted.

Background

A practical data point for assessing information quality and value in the Electronic Health Record (EHR) is the professional category of the EHR author. We evaluated and compared free form electronic signatures against LOINC note titles in categorizing the profession of EHR authors.

Methods

A random 1000 clinical document sample was selected and divided into 500 document sets for training and testing. The gold standard for provider classification was generated by dual clinician manual review, disagreements resolved by a third reviewer. Text matching algorithms composed of document titles and author electronic signatures for provider classification were developed on the training set.

Results

Overall, detection of professional classification by note titles alone resulted in 76.1% sensitivity and 69.4% specificity. The aggregate of note titles with electronic signatures resulted in 95.7% sensitivity and 98.5% specificity.

Conclusions

Note titles alone provided fair professional classification. Inclusion of author electronic signatures significantly boosted classification performance.

Adenomatous polyps are known precursor lesions for colorectal cancer and some hyperplastic polyps also have malignant potential. The use of aspirin and non-steroidal anti-inflammatory drugs (NSAIDS) is associated with a reduced risk of adenomatous polyps; however, less evidence exists regarding NSAID use and hyperplastic polyp risk. We conducted a colonoscopy-based case-control study including 2028 polyp cases (1,529 adenomatous and 499 hyperplastic) and 3,431 polyp-free controls. Multivariate logistic regression models were constructed to derived adjusted odds ratios (OR) and 95% confidence intervals (CI) as the measure of the association between NSAID use and polyp risk. Use of baby aspirin, regular aspirin, and non-aspirin NSAIDs, were associated with a reduced risk of adenomatous polyps (OR = 0.79; 95% CI 0.66–0.93, OR = 0.73; 0.58–0.90, and OR = 0.67; 0.53–0.86, respectively). Baby aspirin was also associated with a reduced risk of hyperplastic polyps (OR = 0.74; 0.56–0.97). Although a dose response was seen with adenoma risk and regular use of any NSAIDs (less than 7 doses per week, 7 doses per week, and greater than 7 doses per week), a dose response was not seen with hyperplastic polyps. We found no evidence of interaction between NSAID dose and duration and polyp risk. The use of any NSAID regardless of type was associated with a reduced risk of adenomatous polyps however regular aspirin and COX-2 inhibitors use was not associated with hyperplastic polyp risk.

Purpose

To examine whether body mass index is associated with reduced colorectal cancer (CRC) screening in a large population of black and white adults.

Methods

Cross-sectional data collected at baseline for 9,547 black males, 14,515 black females, 3,519 white males, and 7,245 white females age 50–79 enrolled in the Southern Community Cohort Study from 2002–2009 were used to examine odds ratios (OR) with 95% confidence internals (CI) for use of colonoscopy or sigmoidoscopy in relation to body mass index (BMI) categories (<18.5, 18.5–24.9 (referent), 25–29.9, 30–34.9, 35–39.9, and 40+ (extreme obesity), kg/m2) using logistic regression controlling for age, education, income, health insurance status, last physician visit, cigarette smoking, and alcohol consumption.

Results

Increased BMI was not associated with reduced CRC screening among whites (OR [95% CI] for BMI ≥ 40 = 1.02 [0.71–1.46] for white males and 0.99 [0.83–1.19] for white females), and odds of CRC screening were increased with high BMI among blacks (OR [95% CI] for BMI ≥ 40 = 1.34 [1.03–1.74] for black males and 1.13 [0.98–1.29] for black females). Extreme obesity was associated with reduced odds of CRC screening only among white women in subgroup analyses limited to those with health insurance or income ≥ $25,000/year.

Conclusions

Elevated BMI was not a deterrent to CRC screening overall in this population. In light of low overall screening rates for colorectal cancer nationally, efforts to increase screening in all individuals should remain the focus of public health initiatives.

A significant proportion of men engage in sexual relationships with other men which has direct health implications, but the unique health care needs of these patients are often ignored or overlooked. Moreover, due to a fear of stigmatization by the medical community, one of the more significant health risks for men who have sex with men (MSM) may be that they avoid routine or appropriate health care. Physicians and other providers can help overcome this barrier and improve the health care of MSM by keeping a non-judgmental attitude toward these patients, differentiating sexual behaviour from sexual identity, communicating with gender neutral terms, and maintaining awareness of how their own attitudes affect clinical judgment. The purpose of this article is to help contextualize health issues affecting MSM and provide a framework for physicians and other providers to deliver optimum and appropriate health care for men who have sex with men in India.

ABSTRACT

The disabling disorder known as chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME) has been linked in two independent studies to infection with xenotropic murine leukemia virus-related virus (XMRV) and polytropic murine leukemia virus (pMLV). Although the associations were not confirmed in subsequent studies by other investigators, patients continue to question the consensus of the scientific community in rejecting the validity of the association. Here we report blinded analysis of peripheral blood from a rigorously characterized, geographically diverse population of 147 patients with CFS/ME and 146 healthy subjects by the investigators describing the original association. This analysis reveals no evidence of either XMRV or pMLV infection.

IMPORTANCE

Chronic fatigue syndrome/myalgic encephalomyelitis has an estimated prevalence of 42/10,000 in the United States, with annual direct medical costs of $7 billion. Here, the original investigators who found XMRV and pMLV (polytropic murine leukemia virus) in blood of subjects with this disorder report that this association is not confirmed in a blinded analysis of samples from rigorously characterized subjects. The increasing frequency with which molecular methods are used for pathogen discovery poses new challenges to public health and support of science. It is imperative that strategies be developed to rapidly and coherently address discoveries so that they can be carried forward for translation to clinical medicine or abandoned to focus resource investment more productively. Our study provides a paradigm for pathogen dediscovery that may be helpful to others working in this field.

Background

The purpose of this study was to evaluate nepafenac ophthalmic suspension 0.1% (Nevanac®; Alcon Research Ltd) in the prevention of macular edema following cataract surgery in diabetic retinopathy patients.

Methods

This was a multicenter, randomized, double-masked, vehicle-controlled study of 263 adult diabetic patients with nonproliferative diabetic retinopathy requiring cataract surgery. Patients were randomized (1:1) to instill nepafenac or vehicle three times daily beginning 1 day prior to surgery through day 90. Efficacy included the percentage of patients who developed macular edema (≥30% increase in central subfield macular thickness from baseline) and the percentage of patients with decreases of more than five letters in best-corrected visual acuity from day 7 to 90.

Results

A significantly lower percentage of patients in the nepafenac group developed macular edema relative to patients in the vehicle group (3.2% versus 16.7%; P < 0.001). A significantly lower percentage of patients in the nepafenac group had best-corrected visual acuity decreases of more than five letters relative to patients in the vehicle group on day 30 (P < 0.001), day 60 (P = 0.002), and day 90 (P = 0.006). The mean central subfield macular thickness and mean percent change from baseline in macular volume were also significantly lower in the nepafenac group versus the vehicle group at days 14 through 90 (P ≤ 0.005). No safety issues or trends were identified when dosing was increased to 90 days that negatively impacted the favorable benefit/risk profile of nepafenac.

Conclusion

Nepafenac demonstrated statistically significant and clinically relevant advantages compared with vehicle in preventing macular edema and maintaining visual acuity in diabetic patients following cataract surgery. These advantages were seen at multiple time points over the course of the 90-day therapy period. There was no clinically relevant increase in risk from 90 days dosing compared with 14 days. Therefore, with a similar safety profile and benefit in preventing macular edema and maintaining vision, the risk/benefit to the diabetic patient undergoing cataract surgery appears to be positive.

The medical community’s efforts to address intimate partner violence (IPV) have often neglected members of the lesbian, gay, bisexual, and transgender (LGBT) population. Heterosexual women are primarily targeted for IPV screening and intervention despite the similar prevalence of IPV in LGBT individuals and its detrimental health effects. Here, we highlight the burden of IPV in LGBT relationships, discuss how LGBT and heterosexual IPV differ, and outline steps clinicians can take to address IPV in their LGBT patients.

The increase in obesity prevalence highlights the need for a more comprehensive understanding of the neural systems controlling food intake; one that extends beyond food intake driven by metabolic need and considers that driven by higher-order cognitive factors. The hippocampus, a brain structure involved in learning and memory function, has recently been linked with food intake control. Here we examine whether administration of the adiposity hormone leptin to the dorsal and ventral sub-regions of the hippocampus influences food intake and memory for food. Leptin (0.1 μg) delivered bilaterally to the ventral hippocampus suppressed food intake and body weight measured 24 h after administration; a higher dose (0.4 μg) was needed to suppress intake following dorsal hippocampal delivery. Leptin administration to the ventral but not dorsal hippocampus blocked the expression of a conditioned place preference for food and increased the latency to run for food in an operant runway paradigm. Additionally, ventral but not dorsal hippocampal leptin delivery suppressed memory consolidation for the spatial location of food, whereas hippocampal leptin delivery had no effect on memory consolidation in a non-spatial appetitive response paradigm. Collectively these findings indicate that ventral hippocampal leptin signaling contributes to the inhibition of food-related memories elicited by contextual stimuli. To conclude, the results support a role for hippocampal leptin signaling in the control of food intake and food-related memory processing.

Karten's neocortex hypothesis holds that many component cell populations of the sauropsid dorsal ventricular ridge (DVR) are homologous to particular cell populations in layers of auditory and visual tectofugal-recipient neocortex of mammals (i.e., temporal neocortex), as well as to some amygdaloid populations. The claustroamygdalar hypothesis, based on gene expression domains, proposes that mammalian homologues of DVR are found in the claustrum, endopiriform nuclei, and/or pallial amygdala. Because hypotheses of homology need to account for the totality of the evidence, the available data on multiple forebrain features of sauropsids and mammals are reviewed here. While some genetic data are compatible with the claustroamygdalar hypothesis, and developmental (epigenetic) data are indecisive, hodological, morphological, and topographical data favor the neocortex hypothesis and are inconsistent with the claustroamygdalar hypothesis. Detailed studies of gene signaling cascades that establish neuronal cell-type identity in DVR, tectofugal-recipient neocortex, and claustroamygdala will be needed to resolve this debate about the evolution of neocortex.

Purpose

To assess the efficacy and safety of 5-fluorouracil (5FU) and gemcitabine administered concurrently with radiation in patients with locally advanced, non-metastatic pancreatic cancer.

Patients and Methods

Eligible patients had histologically confirmed pancreatic adenocarcinoma, deemed locally unresectable without evidence of metastatic disease. In addition, all patients underwent laparoscopy or laparotomy prior to study entry to rule out peritoneal carcinomatosis. Patients received radiation therapy (50.4 Gy) with concurrent infusional 5FU (200 mg/m2, 5 days per week) and weekly gemcitabine (200 mg/m2). After a three-week break, patients received weekly gemcitabine at 1000 mg/m2 for 3 of 4 weeks, for four cycles. The primary endpoint of the trial was the proportion of patients surviving nine months from study entry. Secondary endpoints included objective tumor response, CA19-9 response, overall survival (OS) time to progression (TTP) and toxicity.

Results

Between November 2001 and October 2004, 81 patients were enrolled, of whom 78 were eligible for analysis. With a median follow-up of 55.2 months, the median OS was 12.2 months (95% CI, 10.9 – 14.9 months) and median TTP was 10.0 months (95% CI 6.4 – 12.0 months). An objective tumor response was seen in 19 patients (25%) and among 56 patients with an elevated CA19-9 at baseline, 29 (52%) had a sustained CA19-9 response. Overall, 41% of patients had grade 3 or greater treatment-related GI adverse events.

Conclusion

The combination of 5FU, gemcitabine and radiation is well-tolerated. Survival is comparable to the best results of other recent studies of 5FU and radiation or gemcitabine and radiation.

Recently, a variety of physiologically based pharmacokinetic (PBPK) models have been developed for the essential element manganese. This paper reviews the development of PBPK models (e.g., adult, pregnant, lactating, and neonatal rats, nonhuman primates, and adult, pregnant, lactating, and neonatal humans) and relevant risk assessment applications. Each PBPK model incorporates critical features including dose-dependent saturable tissue capacities and asymmetrical diffusional flux of manganese into brain and other tissues. Varied influx and efflux diffusion rate and binding constants for different brain regions account for the differential increases in regional brain manganese concentrations observed experimentally. We also present novel PBPK simulations to predict manganese tissue concentrations in fetal, neonatal, pregnant, or aged individuals, as well as individuals with liver disease or chronic manganese inhalation. The results of these simulations could help guide risk assessors in the application of uncertainty factors as they establish exposure guidelines for the general public or workers.

OBJECTIVES

To describe the independent contributions of selected medical conditions to the disparity between black and white people in disability rates, controlling for demographic and socioeconomic factors.

DESIGN

Cross-sectional analysis of a community-based cohort.

SETTING

Urban and rural counties of central North Carolina.

PARTICIPANTS

Two thousand nine hundred sixty-six adults aged 68 and older participating in the Duke Established Populations for Epidemiologic Studies of the Elderly (EPESE).

MEASUREMENTS

Self-reported data on sociodemographic characteristics and medical conditions, Short Portable Mental Status Questionnaire, activities of daily living (ADLs).

RESULTS

Fifty-five percent of the cohort was black. Blacks were more likely than whites to report disability (odds ratio = 1.39, 95% confidence interval = 1.15–1.68). Controlling for age, sex, marital status, and socioeconomic status, blacks were more likely to be obese and have diabetes mellitus, and less likely to report vision problems, fractures, and heart attacks. The higher prevalence of obesity and diabetes mellitus in blacks, after adjustment for sociodemographic factors, accounted for more than 30% of the black–white difference in disability. Conversely, the black–white disability gap would be approximately 45% wider if whites had a lower prevalence of fractures and vision impairment, similar to their black peers.

CONCLUSION

Higher rates of obesity and diabetes mellitus in older black Americans account for a large amount of the racial disparity in disability, even after controlling for socioeconomic differences. Culturally appropriate interventions that lower the prevalence or the functional consequences of obesity and diabetes mellitus in blacks could substantially decrease this racial health disparity.

Background.

Metabolic profiling might provide insight into the biologic underpinnings of disability in older adults.

Methods.

A targeted mass spectrometry–based platform was used to identify and quantify 45 plasma acylcarnitines in 77 older men with a mean age of 79 years and average body mass index of 28.4 kg/m2. To control for type I error inherent in a test of multiple analytes, principal components analysis was employed to reduce the acylcarnitines from 45 separate metabolites, into a single “acylcarnitine factor.” We then tested for an association between this acylcarnitine factor and multiple indices of physical performance and self-reported function.

Results.

The acylcarnitine factor accounted for 40% of the total variance in 45 acylcarnitines. Of the metabolites analyzed, those that contributed most to our one-factor solution were even-numbered medium and long-chain species with side chains containing 10–18 carbons (factor loadings ≥0.70). Odd-numbered chain species, in contrast, had factor loadings 0.50 or less. Acylcarnitine factor scores were inversely related to physical performance as measured by the Short Physical Performance Battery total score, two of its three component scores (gait and chair stands Short Physical Performance Battery), and usual and maximal gait speeds (ρ = −0.324, −0.348, −0.309, −0.241, and −0.254, respectively; p < .05).

Conclusions.

Higher acylcarnitine factor scores were associated with lower levels of objectively measured physical performance in this group of older, largely overweight men. Metabolic profiles of rodents exhibiting lipid-induced mitochondrial dysfunction show a similar phenotypic predominance of medium- and long-chain acylcarnitines.

Breast cancer is the most common cancer in women. Controversy exists regarding the role of dietary fat in breast cancer etiology. We investigated the association of dietary polyunsaturated fatty acids (PUFA) and the ratio of n-6 PUFAs to marine-derived n-3 PUFAs with breast cancer risk in the Shanghai Women’s Health Study, a prospective cohort study including 72,571 cancer-free participants at baseline. Dietary fatty acid intake was determined using food frequency questionnaires. We used Cox proportional hazards analysis to estimate the relative risks (RR) and 95% confidence intervals (CI) for the association of breast cancer risk with dietary fatty acids consumption. In 583,998 person-years of follow-up, we identified 712 breast cancer cases. We found no association of breast cancer risk to dietary intake of linoleic acid, arachidonic acid, α-linolenic acid, or marine-derived n-3 PUFA. We found a statistically significant interaction between n-6 PUFA intake, marine-derived n-3 PUFA intake and breast cancer risk (p = 0.008). Women with lower intake (the lowest tertile) of marine-derived n-3 PUFA and higher intake (the highest tertile) of n-6 PUFA had an increase risk for breast cancer (RR=2.06; 95% CI=1.27-3.34) compared to women with higher intake (the highest tertile) of marine-derived n-3 PUFAs and lower intake (the lowest tertile) of n-6 PUFAs after adjusting for potential confounders. The relative amounts of n-6 PUFA to marine-derived n-3 PUFAs may be more important for breast cancer risk than individual dietary amounts of these fatty acids.

Summary

Glucagon-like-peptide-1 receptor (GLP-1R) activation within the nucleus tractus solitarius (NTS) suppresses food intake and body weight (BW), but the intracellular signals mediating these effects are unknown. Here, hindbrain (4th icv) GLP-1R activation by Exendin-4 increased PKA and MAPK activity and decreased phosphorylation of AMPK in NTS. PKA and MAPK signaling contribute to food intake and BW suppression by Exendin-4, as inhibitors RpcAMP and U0126 (4th icv), respectively, attenuated Exendin-4's effects. Hindbrain GLP-1R activation inhibited feeding by reducing meal number, not meal size. This effect was attenuated with stimulation of AMPK activity by AICAR (4th icv). The PKA, MAPK and AMPK signaling responses by Ex-4 were present in immortalized GLP-1R-expressing neurons (GT1-7). In conclusion, hindbrain GLP-1R activation suppresses food intake and BW through coordinated PKA-mediated suppression of AMPK and activation of MAPK. Pharmacotherapies targeting these signaling pathways, which mediate intake-suppressive effects of CNS GLP-1R activation, may prove efficacious in treating obesity.