Effects of Vascular Risk Factors on the Association of Blood-Based Biomarkers with Alzheimer's Disease

Background

Comorbidities may influence the levels of blood-based biomarkers for Alzheimer's disease (AD). We investigated whether differences in risk factors or comorbid conditions might explain the discordance between clinical diagnosis and biomarker classifications in a multi-ethnic cohort of elderly individuals.

Aims

To evaluate the relationship of medical conditions and other characteristics, including body mass index (BMI), vascular risk factors, and head injury, with cognitive impairment and blood-based biomarkers of AD, phosphorylated tau (P-tau 181, P-tau 217), in a multi-ethnic cohort.

Methods

Three-hundred individuals, aged 65 and older, were selected from a prospective community-based cohort for equal representation among three racial/ethnic groups: non-Hispanic White, Hispanic/Latino and African American/Black. Participants were classified into four groups based on absence (Asym) or presence (Sym) of cognitive impairment and low (NEG) or high (POS) P-tau 217 or P-tau 181 levels, determined previously in the same cohort: (Asym/NEG, Asym/POS, Sym/NEG, Sym/POS). We examined differences in individual characteristics across the four groups. We performed post-hoc analysis examining the differences across biomarker and cognitive status.

Results

P-tau 217 or P-tau 181 positive individuals had lower BMI than P-tau negative participants, regardless of symptom status. Symptomatic and asymptomatic participants did not differ in terms of BMI. BMI was not a mediator of the effect of P-tau 217 or P-tau 181 on dementia. Frequencies of other risk factors did not differ between the four groups of individuals.

Conclusions

Participants with higher levels of P-tau 217 or P-tau 181 consistent with AD had lower BMI regardless of whether the individual was symptomatic. These findings suggest that weight loss may change with AD biomarker levels before onset of cognitive decline. They do not support BMI as a confounding variable. Further longitudinal studies could explore the relationship of risk factors with clinical diagnoses and biomarkers.

P-249 The location of fragments and degraded zones in blastocysts is associated with ploidy: moving towards explaining an AI-based morphology tool trained on euploidy outcomes

Study question

Is the location of degraded areas or fragments an indication of ploidy in blastocyst images?

Summary answer

Degradation traces observed in a blastocyst’s inner cell mass correlates with aneuploidy when confirmed by trophectoderm biopsy.

What is known already

The interaction between humans and Artificial Intelligence (AI) augmented intelligence, (AuI) is dependent on the AI’s ability to be self-explainable and interpretable. This is a highly desired feature of AI’s in healthcare, given that blindly trusting it to make a decision has serious ethical considerations and potential consequences. Currently, most available AI’s provide “black-box” advice that might cause difficult interaction with their human counterparts. ERICA (IVF2.0 Limited, UK), was designed to rank blastocysts using euploid status as ground truth, and although initially a “black-box,” we describe results from an initial attempt towards making it explainable.

Study design, size, duration

This study was designed as a proof-of-concept on retrospectively collected images. De-identified images (n = 329) with known ploidy status (euploid or aneuploid) were retrieved (November 2021) from ERICA. The images were processed from December 2021 to January 2022.

Participants/materials, setting, methods

A senior embryologist identified visual degenerative traces from blastocyst images for areas of cell degradation and cell fragments. Ploidy status was blinded to the embryologist. Images were segmented for trophectoderm (TE), blastocoele (BC), and inner cell mass (ICM) using the automated tool of ERICA’s algorithm. The distance between the centre of each degenerative trace and the ICM was measured. The Dice Similarity Coefficient (DSC) and the proportion of degenerative traces in each zone were computed.

Main results and the role of chance

We identified some level of degradation in 60% of the blastocysts, particularly in BC:44%, ICM:38%, TE:26%, and ICM+BC:55%, and the presence of fragments in 103, particularly in BC:21%, ICM:10%, and TE:24%. Our database contained 52% euploid blastocyst images.

We found that when DSC between degradation and ICM is more than 10% (44/78 aneuploids) the chances of aneuploidy increase by 25% (Z=-1.76, p < 0.05).

We also found a 13% increased chance of an embryo being aneuploid (92/157 aneuploidy) if the area of ICM+BC has any presence of degradation (Z=-1.14, p = 0.13), and an increased risk of aneuploidy if DSC (U = 12401, p = 0.09), and also if the proportion of degradation was found in ICM+BC (U = 12397, p = 0.09).

Our data also suggests that aneuploid embryos have closer fragments (mean=51um, 95% CI: 42.2-59.9) than euploids (mean=63.4um 95% CI:51.1-75.7) (U = 988,=0.19).

Mann-Whitney U test and Z-test for proportions were used accordingly, both under the hypothesis that increased degenerative traces means a higher probability of being aneuploid (one-tailed test).

Limitations, reasons for caution

Analyzing degenerative traces using a single image from a single focal plane might be limiting. Identifying fragments and degradation might not be a replicable process inter- or intra- embryologist. More annotators are needed to reduce this bias.

Wider implications of the findings

Correlation between aneuploidy and cell degradation was stronger in the ICM than TE, although ploidy status is obtained via TE biopsy. Our data suggest that fragments that are closer to the ICM might increase the chances of aneuploidy. A larger prospective multicentre study should be conducted to confirm these findings.

Trial registration number

not applicable

Second victim phenomenon in a surgical area: Online survey

BACKGROUND AND AIM OF STUDY

An effective and accessible first source of support for second victims (SV) is usually the colleagues themselves, who should have tools to help emotionally and detect the unusual course of a SV. The aim of this work is to assess health professionals' perception of the phenomenon, as well as their capability to apply psychological first aid.

MATERIAL AND METHODS

Observational descriptive study through online surveys answered anonymously. Participants were different health professionals from surgical area, mainly from a third-level hospital.

RESULTS

329 responses, 67 anaesthesiologists, 110 anaesthesiologists in training, 152 nurses. 78.4% had felt SV, more frequent among anaesthesiologists; however, 58% had never heard of the term. Guilt was the most frequent emotion. Residents were more afraid of judgmental colleagues and thought more about drop out their training. From those who sought help, most did it through a colleague, but most did not feel useful in helping a SV. 66% affirmed there is a still punitive, evasive or silent culture about medical incidents.

CONCLUSIONS

Despite the frequency of the phenomenon there is still lack of knowledge of the term SV. Impact of the phenomenon is heterogenous and changes based on experience and responsibility. Colleagues are the first source of emotional help but there is a lack of tools to be able to provide it. Institutions are urged to create training programs so that professionals can guarantee «psychological first aid».

Second victim phenomenon in a surgical area: online survey

BACKGROUND AND AIM OF STUDY

An effective and accessible first source of support for second victims (SV) is usually the colleagues themselves, who should have tools to help emotionally and detect the unusual course of a SV. The aim of this work is to assess health professionals' perception of the phenomenon, as well as their capability to apply psychological first aid.

MATERIAL AND METHODS

Observational descriptive study through online surveys answered anonymously. Participants were different health professionals from surgical area, mainly from a third-level hospital.

RESULTS

329 responses, 67 anaesthesiologists, 110 anaesthesiologists in training, 152 nurses. 78.4% had felt SV, more frequent among anaesthesiologists; however, 58% had never heard of the term. Guilt was the most frequent emotion. Residents were more afraid of judgmental colleagues and thought more about drop out their training. From those who sought help, most did it through a colleague, but most did not feel useful in helping a SV. 66% affirmed there is a still punitive, evasive or silent culture about medical incidents.

CONCLUSIONS

Despite the frequency of the phenomenon there is still lack of knowledge of the term SV. Impact of the phenomenon is heterogenous and changes based on experience and responsibility. Colleagues are the first source of emotional help but there is a lack of tools to be able to provide it. Institutions are urged to create training programs so that professionals can guarantee «psychological first aid».

A pilot randomized controlled trial of a tailored smoking cessation program for people living with HIV in the Washington, D.C. metropolitan area

OBJECTIVE

Morbidity and mortality from smoking-related diseases among people living with HIV (PLWH) in the U.S. surpasses that due to HIV itself. Conventional smoking cessation treatments have not demonstrated strong efficacy among PLWH. We conducted a pilot randomized controlled trial (RCT) to evaluate a tailored smoking cessation intervention based on the minority stress model. We compared standard of care counseling (SOC) to a tailored intervention (TI) including one face-to-face counseling session incorporating cognitive behavioral therapy to build resilience, and 30 days of 2-way text messaging.

RESULTS

The primary outcome was smoking cessation. Secondary outcomes included cigarettes per day (CPD), exhaled carbon monoxide (CO), and cessation self-efficacy. A total of 25 participants were enrolled (TI:11, SOC:14), and 2 were lost to follow-up. There were no significant differences in quit rates between study groups. However, there was a significantly greater decrease in CPD in the TI versus SOC (13.5 vs. 0.0, p-value:0.036). Additionally, self-efficacy increased in both groups (TI p-value:0.012, SOC p-value:0.049) and CO decreased in both groups (TI p-value: < 0.001, SOC p-value:0.049). This intervention shows promise to support smoking cessation among PLWH. A larger study is needed to fully evaluate the efficacy of this approach.

CLINICAL TRIAL

Trial Registration: Retrospectively registered (10/20/2020) NCT04594109.

Screening Nitrate in Forages with a Test Strip: Collaborative Study

A collaborative study was conducted for screening nitrate in forages with a commercially available test strip. The method involves extracting a finely ground sample with deionized water. The test strip is dipped in the sample extract. The color of the reaction zone on the test strip changes from white to pink or purple depending on the nitrate concentration in sample extract. The nitrate present in the extract is determined by comparing the color of the test strip to the color scale on the test strip container. Six blind quintuplicates of forage samples were analyzed by 20 collaborators. Nitrate concentrations in forage samples tested ranged from &lt;1000 ppm nitrate to &gt;10 000 ppm nitrate on dry matter basis. Each collaborator was asked to assign each sample to one of the 4 following nitrate concentration ranges: (1) &lt;1000 ppm, (2) 1000 to 5000 ppm, (3)&gt;5000 ppm to 10 000 ppm, and (4) &gt;10 000 ppm. Nineteen of 20 collaborators reported results. Results from 2 laboratories were rejected as outliers by inspection and χ2 test. Sensitivity rates (p+) ranged from 0.965 to 0.998, with standard errors of 0.006 to 0.16. Specificity rates (p−) ranged from 0.991 to 0.997 for the 4 ranges, with standard errors of 0.003 to 0.006. False-positive rates (pf+) ranged from 0.006 to 0.046, with standard errors of 0.006 to 0.025. False-negative rates (pf−) ranged from 0.003 to 0.007, with standard errors of 0.003 to 0.006. Screening nitrate in forages with a test strip has been adopted first action by AOAC INTERNATIONAL.

P727 Unexpected ventricular aneurysm: further ischemic aetiology

Introduction

Ventricular aneurysm is an infrequent complication of myocardial infarction. In absence of an ischemic event, alternative aetiologies include: thoracic trauma, hypertrophic cardiomyopathy, myocarditis, Chagas disease, cardiac sarcoidosis or arrythmogenic cardiomyopathy. In the absence of any of the previous, congenital aneurysm diagnosis is made.

Case

We present the case of 57-year-old man referred to cardiology department because a new onset of atrial fibrillation with left bundle branch block. Past medical history included high blood pressure and dyslipidaemia without any history or smoking, alcohol consumption or any other toxic abuse. No chest pain, shortness of breath or other significant symptoms were reported. Physical examination was unremarkable except for an arrhythmic pulse at 85-90 bpm.

Echocardiogram showed moderate dilated left ventricle with mild-moderate LV dysfunction (EF 40% ) with a septal aneurysm of 2.4x1cm (Picture A). A coronary CT was performed that ruled out coronary heart disease and confirmed the presence of the septal aneurysm (Picture B). To better characterize this image, a cardiac magnetic resonance (CMR) was performed. Moderate dilated LV with significant dysfunction (EF 31%) was reported. A septal aneurysm of 13 x 22 x 33 mm composed of a 2.8 m thin wall of true myocardial tissue was documented (picture C and D-late gadolinium enhance). No myocardial delayed enhancement was detected in any area of the LV. Moreover, no signs of myocardial non compaction, arrythmogenic cardiomyopathy, hypertrophic cardiomyopathy or myocarditis were seen. Chagas serology as well as sarcoidosis diagnosis work up were negative. Patient denied any thoracic traumatism. Congenital aneurysm diagnosis was finally established.

Electrical cardioversion was performed after 1 month of correct oral anticoagulation and heart failure treatment was started. Case was presented in the Heart Team session and a conservative management was decided based on asymptomatic status and absence of ventricular arrhythmias. After 3 years of clinical follow up, the patients is in good status, asymptomatic and in sinus rhythm. Discussion: Congenital ventricular aneurysm is a rare cardiac malformation that arises during the fourth embryonic week. Most frequently, left ventricular aneurysms are found in the apex and the perivalvular area, being the septal location an atypical one. Most patients are asymptomatic but when symptoms occur, they are mostly related to the presence of ventricular arrhythmias. Aneurysm rupture incidence is variable, ranging from 3.7% to 12 % according to the different series. For this reason, surgery is recommended in symptomatic patients. However, management of asymptomatic patients is not clear since prognosis studies are lacking.

Abstract P727 Figure. A.Echo B.-CT C.-CMR. D.-CMR gadolinium

P1459 Flu-like syndrome complicated in a rare form of infective endocarditis

Background

The HACEK group of organisms are one of the infrequent causes of infective endocarditis (IE)(5% of cases in adults).Cultures require long incubation time and clinical presentation may be insidious,delaying final diagnosis.We report a case of subacute atypical presentation of native mitral valve Haemophilus parainfluenzae IE

A 33 yo female with no history of cardiac disease was presented in our hospital with malaise,weakness &high fever till 39oC for at about two weeks.The patient was treated with levofloxacin and discharged. The 1st blood culture was negative.After 25 days the patient was presented with prolonged fever,neurological signs of TIA(motor aphasia and septic embolic episode of 2nd level on the right hand&foot).Physical exam normal,no cardiac murmurs. ECG:normal. Echo:TTE-mitral valve with thickened leaflet, presence of structures suggestive for vegetations (15x19 mm) at the posterior leaflet, perforation of the posterior leaflet causing an IM mild-moderate.TEE-mitral valve with small posterior leaflet, big anterior leaflet with mobile vegetations of coral-forms with diameter maximum 20x10 mm,located at A3 scallop of mitral valve at posteromedial commissural,with a perforation at this level causing moderate IM.No other pathological findings.Cranial CT scan-no data of any acute intracranial abnormality.Body CT scan-a low uptake area of the renal parenchyma related to acute pyelonephritis/infarction.Blood tests-elevated CRP & thrombocytopenia.Blood culture(2nd one): Haemophilus parainfluenzae.Treatment-The patient went on ceftriaxone and underwent a surgical mitral valve repair with mitral annuloplasty and patch placement because of the size of the vegetation and the embolic risk.We also respect the desire of the patient to be pregnant.The patient improved, no fever. Follow-up:CRP normal.TTE echo showed no evidence of the previously detected vegetation with a residual mild MR.The patient was discharged home followed up after 6 weeks with full recovery.

Discussion

We present the case of a young healthy woman without any diseases,admitted with the symptoms of a simple flu-like syndrome with a negative blood culture, but complicated later in one of the rarest forms of IE with Haemophilus parainfluenzae.

HACEK organisms are most often associated with IE, although rare, can be extremely serious because of the tendency of big size vegetation and embolic episodes,but outcomes generally are successful if the organism is identified early and treated appropriately.The treatment of a HACEK infection is based on the location of the infection,clinical severity and available susceptibility data.According to the ESC recommendations Ceftriaxone or ampicillin/sulbactam is the therapy of choice for patients with HACEK endocarditis in both native and prosthetic-valve endocarditis.Fluoroquinolones may be considered as alternative therapy.Regardless of the agent chosen,treatment should last 4– 6 weeks,depending upon the type of valve involved

Abstract P1459 Figure.

Validation of HIV-infected cohort identification using automated clinical data in the Department of Veterans Affairs

OBJECTIVES

The US Department of Veterans Affairs (VA) is the largest integrated health care provider for HIV-infected patients in the USA. VA data for HIV-specific clinical and quality improvement research are an important resource. We sought to determine the accuracy of using the VA Corporate Data Warehouse (CDW), a fully automated medical records database for all VA users nationally, to identify HIV-infected patients compared with a gold-standard VA HIV Clinical Case Registry (CCR).

METHODS

We assessed the test performance characteristics of each of our CDW criteria-based algorithms (presence of one, two or all of the following: diagnostic codes for HIV, positive HIV laboratory tests, and prescription for HIV medication) by calculating their sensitivity (proportion of HIV-positive patients in the CCR accurately detected as HIV-positive by the CDW algorithm) and positive predictive value (PPV; the proportion of patients identified by the CDW algorithm who were classified as HIV-positive from the CCR).

RESULTS

We found that using a CDW algorithm requiring two of three HIV diagnostic criteria yielded the highest sensitivity (95.2%) with very little trade-off in PPV (93.5%).

CONCLUSIONS

A two diagnostic criteria-based algorithm can be utilized to accurately identify HIV-infected cohorts seen in the nationwide VA health care system.

Systematic Review of School Telehealth Evaluations

School telehealth is an alternative delivery model to increase student health-care access with minimal evaluation to aid decision makers in the adoption or expansion of programs. This systematic review assesses school-based telehealth programs using a dissemination and implementation (D&I) framework to inform practitioners and decision makers of the value of school telehealth. We assessed findings from 20 studies on telehealth published between January 2006 and June 2018 and summarized program evaluation on a range of D&I constructs. The sample population included children in school- or center-based early childhood education under age 22 and included parents, providers, and school personnel across urban and suburban locations. There is some evidence that school telehealth can reduce emergency department visits and improve health status for children with chronic and acute illnesses. Future research should report on barriers and facilitators of implementation of programs, including costs related to application of telehealth services and utilization rates.

B-mode and Doppler sonography of the mammary glands in dairy goats for mastitis diagnosis

This study aimed to evaluate the sonographic characteristics of the udder and teats and to determine the Doppler indexes of mammary artery in healthy and undergoing subclinical and clinical mastitis goats. Thirty animals among Saanen and Alpine Brown goats were arranged in three groups, healthy goats (HG), goats with subclinical mastitis (SMG) and goats with clinical mastitis (CMG). Using the B-mode, the sonographic characteristics (echotexture and echogenicity) and biometry (diameter and area of the udder cistern, diameter and area of the teat cistern and thickness of the teat wall) were evaluated. Using Doppler ultrasonography, the vascular indexes of the mammary artery were obtained. It was observed hyperechogenicity with solid component in the gland cistern when comparing animals with clinical mastitis and healthy mammary tissue. Regarding the echotexture of the breast tissue, there was heterogeneity in the mammary parenchyma on the three groups, for the milk, it was observed homogeneity for animals on HG and SMG and heterogeneity for animals on CMG. Grey-scale quantitative assessment revealed increase in echogenicity (mean value) for all the structures when comparing the three groups. Biometry did not reveal statistical difference between groups, for none of the evaluated structures. Doppler examination of the mammary artery showed the decrease of end diastolic velocity and raise of pulsatility index between groups. The association of B-mode and Doppler ultrasonography is useful for the evaluation of the udder of dairy goats with mastitis. It is a sensitive and specific method for the study of this disease. Doppler mode was unable to establish reliable criteria for diagnosis of subclinical mastitis. Moreover, the quantification of echogenicity is a useful technique for the evaluation of the milk in animals with mastitis; therefore, it is suggested that it can be used as complementary technique for the diagnosis of mastitis in goats.

Silicon-on-insulator shortwave infrared wavelength meter with integrated photodiodes for on-chip laser monitoring

This paper demonstrates a very compact wavelength meter for on-chip laser monitoring in the shortwave infrared wavelength range based on an optimized arrayed waveguide grating (AWG) filter with an integrated photodiode array. The AWG response is designed to obtain large nearest neighbor crosstalk (i.e. large overlap) between output channels, which allows accurately measuring the wavelength of a laser under test using the centroid detection technique. The passive AWG is fabricated on a 220 nm silicon-on-insulator (SOI) platform and is combined with GaInAsSb-based photodiodes. The photodiodes are heterogeneously integrated on the output grating couplers of the AWG using DVS-BCB adhesive bonding. The complete device with AWG and detectors has a footprint of only 2 mm(2) while the measured accuracy and resolution of the detected wavelength is better than 20pm.

Studies of the Room-Temperature Multiferroic Pb(Fe0.5Ta0.5)0.4(Zr0.53Ti0.47)0.6O3: Resonant Ultrasound Spectroscopy, Dielectric, and Magnetic Phenomena

Recently, lead iron tantalate/lead zirconium titanate (PZTFT) was demonstrated to possess large, but unreliable, magnetoelectric coupling at room temperature. Such large coupling would be desirable for device applications but reproducibility would also be critical. To better understand the coupling, the properties of all 3 ferroic order parameters, elastic, electric, and magnetic, believed to be present in the material across a range of temperatures, are investigated. In high temperature elastic data, an anomaly is observed at the orthorhombic mm2 to tetragonal 4mm transition, T_ot = 475 K, and a softening trend is observed as the temperature is increased toward 1300 K, where the material is known to become cubic. Thermal degradation makes it impossible to measure elastic behavior up to this temperature, however. In the low temperature region, there are elastic anomalies near ≈40 K and in the range 160-245 K. The former is interpreted as being due to a magnetic ordering transition and the latter is interpreted as a hysteretic regime of mixed rhombohedral and orthorhombic structures. Electrical and magnetic data collected below room temperature show anomalies at remarkably similar temperature ranges to the elastic data. These observations are used to suggest that the three order parameters in PZTFT are strongly coupled.

Switching ferroelectric domain configurations using both electric and magnetic fields in Pb(Zr,Ti)O3-Pb(Fe,Ta)O3 single-crystal lamellae

Thin single-crystal lamellae cut from Pb(Zr,Ti)O3-Pb(Fe,Ta)O3 ceramic samples have been integrated into simple coplanar capacitor devices. The influence of applied electric and magnetic fields on ferroelectric domain configurations has been mapped, using piezoresponse force microscopy. The extent to which magnetic fields alter the ferroelectric domains was found to be strongly history dependent: after switching had been induced by applying electric fields, the susceptibility of the domains to change under a magnetic field (the effective magnetoelectric coupling parameter) was large. Such large, magnetic field-induced changes resulted in a remanent domain state very similar to the remanent state induced by an electric field. Subsequent magnetic field reversal induced more modest ferroelectric switching.

Magnetic switching of ferroelectric domains at room temperature in multiferroic PZTFT

Single-phase magnetoelectric multiferroics are ferroelectric materials that display some form of magnetism. In addition, magnetic and ferroelectric order parameters are not independent of one another. Thus, the application of either an electric or magnetic field simultaneously alters both the electrical dipole configuration and the magnetic state of the material. The technological possibilities that could arise from magnetoelectric multiferroics are considerable and a range of functional devices has already been envisioned. Realising these devices, however, requires coupling effects to be significant and to occur at room temperature. Although such characteristics can be created in piezoelectric-magnetostrictive composites, to date they have only been weakly evident in single-phase multiferroics. Here in a newly discovered room temperature multiferroic, we demonstrate significant room temperature coupling by monitoring changes in ferroelectric domain patterns induced by magnetic fields. An order of magnitude estimate of the effective coupling coefficient suggests a value of ~1 × 10⁻⁷ sm⁻¹.

Multiferroic materials that exhibit coupled ferromagnetic and ferroelectric characteristics could be useful in the development of non-volatile digital storage. Evans et al. report a single-phase multiferroic material whose room-temperature magnetoelectric coupling appears to be unusually strong.

Arterial blood pressure and aortic responses in obese, age-grouped Zucker rats

Endothelial dysfunction is one of the many proposed mechanisms of hypertension and it may justify, at least in part, the increased blood pressure of hypertensive subjects. Nevertheless, the exact mechanisms involved in the hypertensive condition of obese Zucker rats are unclear. In this study, we measured the arterial blood pressure (tail cuff method) of four groups of seven, female, obese Zucker rats each. The rats of groups 1-4 were 9-12, 15-18, 21-24 and 27-30 weeks old respectively. We also evaluated the responses of aortic rings to KCl, methoxamine and acetylcholine, in these animals. Aortic rings were successively exposed to 80 mM KCl and to methoxamine (10(-8)-10(-5) M). The endothelium-dependent relaxation to acetylcholine (10(-9)-10(-5) M) was also established in the methoxamine-precontracted tissue (precontraction close to 80% of the maximum effect of methoxamine). A clear increase in the arterial blood pressure was observed when the age of these animals increased. The contractile responses to KCl and methoxamine were lower in the aortic rings of rats with increased arterial blood pressure. The response to acetylcholine was lower in the rings from 15-18, 21-24 and 27-30 weeks old rats, than in the younger groups. In conclusion, obese Zucker rats develop hypertension and endothelial dysfunction. Nevertheless, the arterial contractions elicited by depolarization or by α(1)-adrenoceptor stimulation decrease in aged, obese Zucker rats.

Spectrum of the isotropic diffuse gamma-ray emission derived from first-year Fermi Large Area Telescope data

We report on the first Fermi Large Area Telescope (LAT) measurements of the so-called "extragalactic" diffuse gamma-ray emission (EGB). This component of the diffuse gamma-ray emission is generally considered to have an isotropic or nearly isotropic distribution on the sky with diverse contributions discussed in the literature. The derivation of the EGB is based on detailed modeling of the bright foreground diffuse Galactic gamma-ray emission, the detected LAT sources, and the solar gamma-ray emission. We find the spectrum of the EGB is consistent with a power law with a differential spectral index gamma = 2.41 +/- 0.05 and intensity I(>100 MeV) = (1.03 +/- 0.17) x 10(-5) cm(-2) s(-1) sr(-1), where the error is systematics dominated. Our EGB spectrum is featureless, less intense, and softer than that derived from EGRET data.