This document presents the official recommendations of the American Gastroenterological Association (AGA) Institute Technology Assessment on "Image-Enhanced Endoscopy." It was approved by the Clinical Practice and Economics Committee on August 3, 2007, and by the AGA Institute Governing Board September 27, 2007.

OBJECTIVES

We compared use of preventive care among veterans receiving care through the Veterans Health Administration (VHA), Medicare fee-for-service (FFS) plans, and Medicare health maintenance organizations (HMOs).

METHODS

Using both the Costs and Use, and Access to Care files of the Medicare Current Beneficiary Survey (2000-2003), we performed a cross-sectional analysis examining self-reported use of influenza vaccination, pneumococcal vaccination, serum cholesterol screening, and serum prostate-specific antigen measurement among male veterans 65 years or older. Veterans' care was categorized as received through VHA, Medicare FFS, Medicare HMOs, VHA and Medicare FFS, or VHA and Medicare HMOs.

RESULTS

Veterans receiving care through VHA reported 10% greater use of influenza vaccination (P<.05), 14% greater use of pneumococcal vaccination (P<.01), a nonsignificant 6% greater use of serum cholesterol screening (P=.1), and 15% greater use of prostate cancer screening (P<.01) than did veterans receiving care through Medicare HMOs. Veterans receiving care through Medicare FFS reported less use of all 4 preventive measures (P<.01) than did veterans receiving care through Medicare HMOs.

CONCLUSIONS

Receiving care through VHA was associated with greater use of preventive care.

Increased signaling by G(i)-coupled receptors has been implicated in dilated cardiomyopathy. To investigate the mechanisms, we used transgenic mice that develop dilated cardiomyopathy after conditional expression of a cardiac-targeted G(i)-coupled receptor (Ro1). Activation of G(i) signaling by the Ro1 agonist spiradoline caused decreased cellular cAMP levels and bradycardia in Langendorff-perfused hearts. However, acute termination of Ro1 signaling with the antagonist nor-binaltorphimine did not reverse the Ro1-induced contractile dysfunction, indicating that Ro1 cardiomyopathy was not due to acute effects of receptor signaling. Early after initiation of Ro1 expression, there was a 40% reduction in the abundance of the sarcoplasmic reticulum Ca(2+)-ATPase (P < 0.05); thereafter, there was progressive impairment of both Ca(2+) handling and force development assessed with ventricular trabeculae. Six weeks after initiation of Ro1 expression, systolic Ca(2+) concentration was reduced to 0.61 +/- 0.08 vs. 0.91 +/- 0.07 microM for control (n = 6-8; P < 0.05), diastolic Ca(2+) concentration was elevated to 0.41 +/- 0.07 vs. 0.23 +/- 0.06 microM for control (n = 6-8; P < 0.01), and the decline phase of the Ca(2+) transient (time from peak to 50% decline) was slowed to 0.25 +/- 0.02 s vs. 0.13 +/- 0.02 s for control (n = 6-8; P < 0.01). Early after initiation of Ro1 expression, there was a ninefold elevation of matrix metalloproteinase-2 (P < 0.01), which is known to cause myofilament injury. Consistent with this, 6 wk after initiation of Ro1 expression, Ca(2+)-saturated myofilament force in skinned trabeculae was reduced to 21 +/- 2 vs. 38 +/- 0.1 mN/mm(2) for controls (n = 3; P < 0.01). Furthermore, electron micrographs revealed extensive myofilament damage. These findings may have implications for some forms of human heart failure in which increased activity of G(i)-coupled receptors leads to impaired Ca(2+) handling and myofilament injury, contributing to impaired ventricular pump function and heart failure.

Solid organ transplantation in human immunodeficiency virus (HIV)-infected individuals requiring concomitant use of immunosuppressants (IS) (e.g. cyclosporine [CsA], sirolimus [SrL], tacrolimus [FK]) and antiretrovirals (ARVs) (e.g. protease inhibitors [PIs] and/or nonnucleoside reverse transcriptase inhibitors [NNRTIs]) is complicated by significant drug interactions. To assist in appropriate clinical management, we describe the pharmacokinetics and dosing modifications in 35 patients (20 kidney, 13 liver and two kidney-liver HIV-infected subjects with end-stage kidney or liver disease), on both IS and NNRTIs, PIs, and combined NNRTIs + PIs, in studies done at weeks 2-4 and/or 12 weeks after transplantation or after a change in IS or ARV drug regimen (n = 97 studies). CsA, SrL and FK concentrations were measured in whole blood by LC/MS. HIV-infected transplant recipients using PIs with IS had marked increases in CsA, FK or SrL trough levels compared to those on NNRTIs alone or to patients not on ARVs, necessitating either a reduction in dose or an increase in dosing interval. Subjects on efavirenz (EFV) and CsA required much higher doses of CsA than those using any other ARV. Changes in antiretroviral therapy should be carefully managed to avoid insufficient immunosuppression or toxicity due to drug interactions.

BACKGROUND AND METHODS

HIV-infected patients receiving antiretroviral therapy often develop changes in body fat distribution; the dominant change is reduction in sc adipose tissue (SAT). Because adipose tissue makes important hormones involved in whole-body energy metabolism, including leptin and adiponectin, we examined plasma concentrations and their relationship to regional adiposity measured by magnetic resonance imaging in 1143 HIV-infected persons (803 men and 340 women) and 286 controls (151 men and 135 women) in a cross-sectional analysis of the FRAM study.

RESULTS

Total and regional adiposity correlated positively with leptin levels in HIV-infected subjects and controls (P < 0.0001). In controls, total and regional adiposity correlated negatively with adiponectin. In HIV-infected subjects, adiponectin was not significantly correlated with total adiposity, but the normal negative correlation with visceral adipose tissue and upper trunk SAT was maintained. However, leg SAT was positively associated with adiponectin in HIV-infected subjects. Within the lower decile of leg SAT for controls, HIV-infected subjects had paradoxically lower adiponectin concentrations compared with controls (men: HIV 4.1 microg/ml vs. control 7.5 microg/ml, P = 0.009; women: HIV 7.8 microg/ml vs. control 11.6 microg/ml, P = 0.037). Even after controlling for leg SAT, exposure to stavudine was associated with lower adiponectin, predominantly in those with lipoatrophy.

CONCLUSION

The normal relationships between adiponectin levels and total and leg adiposity are lost in HIV-infected subjects, possibly due to changes in adipocyte function associated with HIV lipodystrophy, whereas the inverse association of adiponectin and visceral adipose tissue is maintained. In contrast, the relationship between adiposity and leptin levels appears similar to controls and unaffected by HIV lipodystrophy.