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Biomedical subjects

Alan Bloom

Publications and source records attributed to Alan Bloom.

7 recordsLinked to original sources
PubMed2006

Peripheral blood pressure changes induced by dobutamine do not alter BOLD signals in the human brain.

In extending the use of functional MRI to neuropharmacology, a primary area of concern is that peripheral blood pressure changes induced by pharmacological agents could independently produce a change in the blood oxygenation level-dependent (BOLD) signal, resulting in difficulties distinguishing or interpreting drug-induced neural activations. In the present study, we utilized intravenous dobutamine, a beta-adrenergic receptor agonist, to increase the mean arterial blood pressure (MABP), while examining the effects of MABP changes on the BOLD signal in cocaine-dependent participants. Dobutamine infusion significantly increased the MABP from 93 +/- 8 mm Hg to 106 +/- 12 mm Hg (P < 0.0005), but did not produce a significant global BOLD signal. Yet, a few voxels in the anterior cingulate showed BOLD signal changes that paralleled the changes in blood pressure (BP). Our observations support the conclusion that following the infusion of psychoactive agents, brain BOLD signals accurately reflect neuronal activity, even in the face of relatively large peripheral cardiovascular effects that transiently increase systemic BP.

Adrenergic beta-Agonists↗
PubMed2006

A validation of event-related FMRI comparisons between users of cocaine, nicotine, or cannabis and control subjects.

OBJECTIVE: Noninvasive brain imaging techniques are a powerful tool for researching the effects of drug abuse on brain activation measures. However, because many drugs have direct vascular effects, the validity of techniques that depend on blood flow measures as a reflection of neuronal activity may be called into question. This may be of particular concern in event-related functional magnetic resonance imaging (fMRI), where current analytic techniques search for a specific shape in the hemodynamic response to neuronal activity. METHOD: To investigate possible alterations in task-related activation as a result of drug abuse, fMRI scans were conducted on subjects in four groups as they performed a simple event-related finger-tapping task: users of cocaine, nicotine, or cannabis and control subjects. RESULTS: Activation measures, as determined by two different analytic methods, did not differ between the groups. A comparison between an intravenous saline and an intravenous cocaine condition in cocaine users found a similar null result. Further in-depth analyses of the shape of the hemodynamic responses in each group also showed no differences. CONCLUSIONS: This study demonstrates that drug groups may be compared with control subjects using event-related fMRI without the need for any post hoc procedures to correct for possible drug-induced cardiovascular alterations. Thus, fMRI activation differences reported between these drug groups can be more confidently interpreted as reflecting neuronal differences.

Adult↗
PubMed2003

The demise of the small HMO in California.

On May 25, 2001, the California Department of Managed Health Care served Maxicare, a Los Angeles-based HMO with approximately 250,000 subscribers, a notice of conservatorship. Within the following 16 months, four other small California HMOs either filed for bankruptcy or were put under state conservatorship. The age of the small HMO in California had come to an end.

Bankruptcy↗
PubMed2002

Hepatic artery pseudoaneurysm after liver transplantation. A result of transhepatic biliary drainage for primary sclerosing cholangitis.

Hepatic artery pseudoaneurysm (HAP) is a rare but often life-threatening complication of liver transplantation. Treatment is usually ligation, revascularization, or retransplantation. We report a patient suffering from primary sclerosing cholangitis who required transhepatic percutaneous biliary drainage. Following orthotopic liver transplantion (OLT), he developed HAP, which was successfully embolized angiographically. We discuss the association between transhepatic biliary drainage and the development of HAP after OLT, and the possibilities for angiographic intervention in these cases.

Aneurysm, False↗
PubMed2002

Supreme court upholds state independent review laws: does this help or hinder health plans?

"U.S. Supreme Court Deals Blow to HMOs," trumpeted the CNN headline on June 20, 2002. In Rush Prudential HMO, Inc. v. Debra C. Moran, the United States Supreme Court ruled that state laws requiring external review of health plan/HMO decisions regarding medical necessity of covered services did not violate the federal Employee Retirement Income Security Act and were therefore enforceable. If the media is to be believed, requiring HMOs to give second opinions, i.e., external review, is a major blow. However, a review of the case and the fact that the decision was based on a 5-4 vote reveal that lasting lessons from the decision are probably fewer than the press would have one believe.

Employee Retirement Income Security Act↗