Localized two-dimensional shift correlated MR spectroscopy of human brain

A two-dimensional (2D) chemical shift correlated MR spectroscopic (COSY) sequence integrated into a new volume localization technique (90 degrees -180 degrees -90 degrees ) is proposed for whole-body MR spectroscopy (MRS). Using the product operator formalism, a theoretical calculation of the volume localization as well as the coherence transfer efficiencies in 2D MRS is presented. Phantom model solutions were used to test and optimize the efficiency of the proposed sequence. A combination of different MRI transmit/receive RF coils was used: a head MRI coil and a 3" surface coil receive combined with a body coil transmit. The J cross-peaks due to N-acetyl aspartate (NAA), glutamate/glutamine (Glx), myo-inositol (mI), creatine (Cr), choline (Ch), aspartate (Asp), gamma-aminobutyrate (GABA), taurine (Tau), glutathione (GSH), threonine (Thr), and macromolecules (MM) were identified. The cross-peak intensities excited by the proposed 2D sequence were asymmetric with respect to the diagonal peaks. Localized COSY (L-COSY) spectra of cerebral prefrontal and occipital gray/white matter regions in 15 healthy controls are presented. Magn Reson Med 46:58-67, 2001.

The impact of antidepressant discontinuation versus antidepressant continuation on 1-year risk for relapse of bipolar depression: a retrospective chart review

BACKGROUND

Current treatment guidelines recommend discontinuation of an antidepressant within 3 to 6 months after remission of depression in patients with bipolar illness. Yet few studies directly compare the impact of antidepressant discontinuation versus antidepressant continuation on the risk for depressive relapse in patients with bipolar disorder who have been successfully treated for a depressive episode.

METHOD

In a retrospective chart review, patients with DSM-IV bipolar disorder who were treated for an index episode of depression by adding antidepressant medication to ongoing mood stabilizer medications were identified. The risk of depressive relapse in 25 subjects who stopped antidepressant medications after improvement was compared with the risk of depressive relapse in 19 subjects who continued antidepressants after improvement.

RESULTS

Termination of antidepressant medication significantly increased the risk of a depressive relapse. Antidepressant continuation was not significantly associated with an increased risk of mania.

CONCLUSION

While this study may have been limited by the retrospective nature of the chart review, nonrandomized assignment of treatment, and reliance on unstructured progress notes, it suggests that antidepressant discontinuation may increase the risk of depressive relapse in some patients with bipolar disorder. Further research is needed to clarify whether maintenance antidepressant treatment may be warranted in some patients with bipolar disorder, especially in those with frequent recurrent depressive episodes.

Epithelial defensins impair adenoviral infection: implication for adenovirus-mediated gene therapy

Epithelial cells have been to participate actively in host defense by producing small cationic peptides called defensins. To investigate the biological activity of epithelial defensins in more detail, we expressed two defensins, hBD-1 and HD-5, in eukaryotic cell lines. Defensins were localized in the cytoplasm and in cell culture medium and exhibited strong microbicidal activity toward Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Moreover, our data indicate that the presence of defensins protected the cells from adenoviral infection. The presence of HD-5 or hBD-1 reduced the infectivity of Av1CF2 three- to fivefold. These results imply that defensins must be considered a serious obstacle whenever adenovirus is used to deliver genes to epithelial cells.

Endoplasmic reticulum stress and the unfolded protein response in nonalcoholic fatty liver disease

The underlying causes of nonalcoholic fatty liver disease (NAFLD) are unclear, although recent evidence has implicated the endoplasmic reticulum (ER) in both the development of steatosis and progression to nonalcoholic steatohepatitis. Disruption of ER homeostasis, often termed "ER stress," has been observed in liver and adipose tissue of humans with NAFLD and/or obesity. Importantly, the signaling pathway activated by disruption of ER homeostasis, the unfolded protein response, has been linked to lipid biosynthesis, insulin action, inflammation, and apoptosis. Therefore, understanding the mechanisms that disrupt ER homeostasis in NAFLD and the role of ER-mediated signaling have become topics of intense investigation. The present review will examine the ER and the unfolded protein response in the context of NAFLD.

Olanzapine in treatment-resistant bipolar disorder

BACKGROUND

We evaluated the response to olanzapine in 14 consecutive patients with bipolar I disorder who were inadequately responsive to standard psychotropic agents.

METHODS

Fourteen patients with bipolar I disorder by DSM-IV criteria experiencing persistent affective symptoms inadequately responsive to at least one standard mood stabilizer were treated with open-label olanzapine by one of the authors. Response was assessed with the Clinical Global Impression Scale modified for use in bipolar disorder (CGI-BP).

RESULTS

The 14 patients received olanzapine at a mean (SD dosage of 14.1+/-7.2 (range 5-30) mg/day for a mean+/-SD of 101.4+/-56.3 (range 30-217) days of treatment. Of the 14 patients, 8 (57%) displayed much or very much overall improvement in their illness. In general, olanzapine was well tolerated. The most common side effects were sedation, tremor, dry mouth, and appetite stimulation with weight gain.

LIMITATIONS

Data were obtained nonblindly and without a randomized control group, and olanzapine was added to ongoing psychotropic regimens.

CONCLUSION

Olanzapine may have antimanic and mood-stabilizing effects in some patients with bipolar disorder, and is generally well tolerated. Controlled studies of olanzapine in bipolar disorder appear warranted.

Mitochondrial haplotypes and the New Zealand origin of clonal European Potamopyrgus, an invasive aquatic snail

The small aquatic snail Potamopyrgus antipodarum is an important invading species in Europe, Australia and North America. European populations are generally believed to derive from accidental introductions from New Zealand, probably dating back to the mid-19th century. We have employed mitochondrial DNA sequences to test the proposed New Zealand origin of European Potamopyrgus, and to learn more about its genealogical history. Using a 481-bp region of the 16S ribosomal RNA gene, we identified 17 distinct haplotypes among 65 snails from New Zealand. In marked contrast, only two haplotypes were found across all European samples, which cover a large geographical area. Importantly, these two haplotypes are shared with snails from the North Island of New Zealand. Due to sampling limitations we cannot rule out a South Island origin for one of the haplotypes, but our results clearly demonstrate the New Zealand origin of European populations. The marked divergence among the two European haplotypes implies the successful colonization by two distinct mitochondrial lineages, which is consistent with previous data based on nuclear markers.

Lamotrigine for the treatment of bipolar disorder: a clinical case series

BACKGROUND

Recently, a number of new agents have become available to treat bipolar disorder, however many patients may not respond fully even when used in combination. Early reports in epilepsy studies suggested mood-related effects of lamotrigine treatment, as have preliminary reports in bipolar patients.

METHODS

Seventeen patients meeting DSM-IV criteria for bipolar I (n = 9) or bipolar II (n = 8) disorder displaying affective symptoms and a past history of inadequate response or tolerability to at least two standard mood stabilizing agents were recruited through the Stanley Foundation Bipolar Network and treated with the new anticonvulsant lamotrigine in an add-on, open-label study. Response to therapy was assessed using the Clinical Global Impression Scale modified for bipolar disorder.

RESULTS

The mean dose of lamotrigine was 187+/-157 mg/day (range 50-600 mg/day) for a mean duration of 159+/-109 days (range 14-455 days). Eleven (65%) patients were rated as very much or much improved. Lamotrigine was well tolerated, and may have mood stabilizing and antidepressant properties in some patients with bipolar disorder.

LIMITATIONS

The study is hypothesis generating because it was uncontrolled and open. Controlled studies are warranted.

CONCLUSIONS

This preliminary report supports clinical improvement for both mood cycling and depression in patients with bipolar disorder treated with lamotrigine.

Expression of human alpha-defensin 5 (HD5) mRNA in nasal and bronchial epithelial cells

BACKGROUND/AIMS

Human defensins are antibiotic peptides expressed in myeloid and epithelial cells. Human alpha-defensin 5 (HD5) has been detected in Paneth cell granules in the crypts of Lieberkühn and has recently been identified in the female reproductive tract. The aim of this study was to investigate the presence of HD5 mRNA in nasal and bronchial epithelial cells.

METHODS/RESULTS

Semiquantitative reverse transcription polymerase chain reaction (RT-PCR) analysis showed that HD5 mRNA was expressed infrequently and to varying degrees in bronchial and nasal epithelial cells. In situ hybridisation resulted in a positive signal in the epithelial layer of nasal polyps. HD5 mRNA was locally restricted to a specific area of epithelial cells and also occurred in submucosal glands.

CONCLUSIONS

HD5 mRNA expression in nasal and bronchial epithelial cells is rare and seemed to be locally induced. The results indicate that HD5 might play a role in innate defence in nasal and bronchial epithelia.

Differential expression of human alpha- and beta-defensins mRNA in gastrointestinal epithelia

BACKGROUND

While defensins have received great attention for their role in bronchial innate immune defence, little is known about the expression levels of the four human epithelial defensins (HD5, HD6, hBD1 and hBD2) in the digestive tract. In this study we quantified the alpha- and beta-defensins mRNA in biopsies obtained from the gastrointestinal mucosa and identified the cells expressing the beta-defensin hBD1 mRNA in ileal mucosa.

MATERIAL AND METHODS

Biopsies from human stomach (corpus and antrum), duodenum, jejunum, ileum and colon were analysed for their expression of alpha- and beta-defensins. The mRNA of defensins was quantified by semiquantitative reverse transcription-polymerase chain reaction. Cells expressing beta-defensin hBD1 mRNA were identified by in situ hybridization with 35S-labelled RNA probes in tissue sections of human ileum.

RESULTS

The hBD1 mRNA was expressed at low levels with little variability throughout the gastrointestinal tract and was detected in all epithelial cells of ileal mucosa. HD5 and HD6 mRNA expression was restricted to the intestine and displayed high interindividual variability. The highest expression levels were observed in jejunum and ileum. Biopsies obtained from duodenum displayed low levels or no expression of HD5 and HD6. The expression level increased considerably in a biopsy obtained from a patient with acute coeliac sprue. In contrast, low levels were observed in a biopsy from a patient with coeliac sprue in remission.

CONCLUSIONS

The expression levels of hBD1, HD5 and HD6 throughout the gastrointestinal tract are tissue and peptide specific and these defensins are expressed with high interindividual variability.

Gabapentin in the acute treatment of refractory bipolar disorder

BACKGROUND

Gabapentin, a new anti-epileptic agent, has been anecdotally reported to be effective in the treatment of mania. We systematically assessed the response rate in bipolar patients being treated adjunctively with gabapentin for manic symptoms, depressive symptoms, or rapid cycling not responsive to standard treatments.

METHOD

Twenty-eight bipolar patients experiencing manic (n = 18), depressive (n = 5), or rapid-cycling (n = 5) symptoms inadequately responsive to at least one mood stabilizer were treated in an open fashion with adjunctive gabapentin. Illness response was assessed using the Clinical Global Impression Scale modified for bipolar disorder (CGI-BP). A 'positive response' was operationalized as a CGI response of much or very much improved.

RESULTS

Fourteen of the 18 (78%) treated for hypomania or mania had a positive response to a dosage range of 600-3,600 mg/day. Patients with hypomania responded fastest, with a positive response achieved in 12.7 +/- 7.2 days. Patients with classic mania had a mean time to positive response of 25 +/- 12 days, and in patients with mixed mania it was 31.8 +/- 20.9 days. All of the five patients treated for depression had a positive response within 21 +/- 13.9 days. Only one of five patients with rapid cycling had a positive response. Gabapentin was well tolerated by all patients, with the most common side-effect being sedation.

CONCLUSIONS

Gabapentin appears to have acute anti-manic and anti-depressant properties as an adjunctive agent for refractory bipolar illness. Prospective double-blind studies are needed to further delineate its acute efficacy when used as monotherapy and its prophylactic efficacy as monotherapy or in conjuction with other mood stabilizers.

Expression of human beta-defensin-1 promotes differentiation of keratinocytes

Epithelial cells have been shown to express the antibiotic peptides human beta-defensins-1 and 2. While beta-defensin-2 is known to be up-regulated by bacterial factors and proinflammatory mediators, the expression of beta-defensin-1 does not appear to be affected by these mediators. To determine the regulation and function of beta-defensin-1 we analyzed its expression upon stimulation of inflammatory mediators in vitro and ex vivo. In immortalized human cell lines (HaCaT) and nasal polyps beta-defensin-1 was not induced upon incubation with bacteria or proinflammatory mediators, suggesting that the inertness of beta-defensin-1 expression levels is not the result of the shortcoming of HaCaT cells. As proliferation and regeneration play an important role at sites of inflammation, we examined the expression level of beta-defensin-1 in relation to the differentiation and proliferation of HaCaT cells. beta-defensin-1 mRNA levels remained low during proliferation but were highly induced upon differentiation. In contrast, beta-defensin-2 expression was unaffected under these conditions. To examine the function of beta-defensin-1 in cellular proliferation and differentiation processes beta-defensin-1 was overexpressed in keratinocytes. Protein expression analysis of the differentiation marker keratin 10 revealed that its expression is highly induced in the presence of increased concentrations of beta-defensin-1. Hence our data indicate that high expression of beta-defensin-1 promotes cell differentiation processes of keratinocytes.

Fatty acid-mediated endoplasmic reticulum stress in vivo: differential response to the infusion of Soybean and Lard Oil in rats

BACKGROUND

In cell systems, saturated fatty acids, compared to unsaturated fatty acids, induce a greater degree of ER stress and inflammatory signaling in a number of cell types, including hepatocytes and adipocytes. The aim of the present study was to determine the effects of infusions of lard oil (enriched in saturated fatty acids) and soybean oil (enriched in unsaturated fatty acids) on liver and adipose tissue ER stress and inflammatory signaling in vivo.

METHODS

Lipid emulsions containing glycerol, phosphatidylcholine, antibiotics (Control, n=7) and either soybean oil (Soybean, n=7) or lard oil (Lard, n=7) were infused intravenously into rats over a 4 h period.

RESULTS

Plasma free fatty acid levels were 0.5±0.1 mmol/L (mean±SD) in Control and were increased to 1.0±0.3 mmol/L and 1.1±0.3 mmol/L in Soybean and Lard, respectively. Glucose and insulin levels were not different among groups. Markers of endoplasmic reticulum (ER) stress and activation of inflammatory pathway signaling were increased in liver and adipose tissue from Soybean and Lard compared to Control, but were increased to a greater extent in Lard compared to Soybean.

CONCLUSIONS

These data suggest that elevated plasma free fatty acids can induce hepatic and adipose tissue ER stress and inflammation in vivo. In addition, saturated fatty acids appear to be more cytotoxic than unsaturated fatty acids in vivo.

Effects of racing on reticulocyte concentrations in Greyhounds

BACKGROUND

Greyhounds have several hematologic variables that are outside of the respective reference intervals of other dog breeds. In addition, increases in HCT, total protein and HGB concentration, and RBC and WBC counts occur immediately after exercise; these values return to resting values within a few hour after racing.

OBJECTIVE

This study evaluated the effects of exercise on the concentration of reticulocytes in circulating blood in racing Greyhounds. We hypothesized that reticulocyte numbers are significantly increased immediately after a race, and return to baseline within one to 2 h postrace.

METHODS

Fifty actively racing Greyhounds at the Wheeling Island Racetrack and Casino were included in the study. Samples were collected by jugular venipuncture one day prior to racing at the kennel (resting), immediately after racing, and one to 2 h after the race (recovery). Reticulocyte counts were determined with an IDEXX ProCyte Dx Hematology Analyzer (IDEXX Laboratories, Inc., Westbrook, ME, USA). Due to a nonparametric distribution, the results were statistically compared using the Friedman test.

RESULTS

Reticulocyte concentrations were significantly different among the 3 sample collection times (P < .0001). There was a significant increase in reticulocyte concentration immediately after racing (P < .001); one to 2 h after racing, the reticulocyte numbers decreased significantly (P < .001) to counts comparable to resting samples.

CONCLUSION

The increase in reticulocyte concentration is probably related to splenic contraction secondary to the release of catecholamines, although premature bone marrow release could also account for these changes. Thus, it is important to consider a Greyhound's activity and degree of excitement when interpreting selected hematologic data in a clinical setting.

Haematological and biochemical values in North American Scottish deerhounds

OBJECTIVE

Sighthounds, including deerhounds, have unique physiological traits that result in laboratory test results that may lie outside reference intervals for the general dog population. Although reference intervals for most analytes are thought to be similar among sighthounds, breed-specific reference intervals are available mainly for greyhounds. The aim of this study was to establish reference intervals for haematology and serum biochemical profiles in deerhounds.

METHODS

Venous blood samples were collected from healthy deerhounds. Haematological and biochemical analytes were examined and reference intervals were established using the 5th and 95th percentiles.

RESULTS

The reference intervals obtained from 96 dogs for platelets, reticulocytes, total thyroxine, chloride, gamma glutamyl transferase, bilirubin and glucose were lower than the general dog population. Reference intervals for mean cell volume, potassium, urea, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and cholesterol were higher than the general dog population. Reference intervals for eosinophils and globulin were wider than that of the general population.

CLINICAL SIGNIFICANCE

These results confirm that differences in haematological and biochemical values exist in the deerhound. Some appear to be shared by all sighthounds but others may be unique to this breed.

Single arterial puncture vs arterial cannula for arterial gas analysis after exercise. Change in arterial oxygen tension over time

In an attempt to find the least invasive, safest, easiest, and cheapest method of obtaining resting and exercise samples of arterial blood, a comparison was made between samples from an arterial needle puncture and an arterial cannula. This study demonstrated that samples of arterial blood may be obtained by radial arterial puncture both at rest and during exercise in practically all cases without morbidity. Samples from arterial needle puncture provide the same results as those from arterial cannulas. In the very rare patient in whom arterial puncture during maximal exercise is unsuccessful, the arterial oxygen pressure (PaO2) measured at 10 seconds after exercise correlates very well with the PaO2 at maximal exercise, and the 15-second value correlates nearly as well. Arterial cannulas are needed in the infrequent case when arterial puncture is not accomplished during maximal exercise and the 10-second or 15-second PaO2 decreases from the resting value. In this instance, determination of the exact extent of the hypoxemia requires an exercise sample obtained by cannula; however, the decrease in PaO2 obtained by arterial needle puncture at 10 or 15 seconds will be all that is needed many times to make a clinical decision. Values obtained at 20 seconds after maximal exercise reflect less of the exercise measurement and cannot be used; however, all episodes of significant hypoxemia (PaO2 less than 60 mm Hg) were captured by the analysis at 20 seconds after exercise.

SS06-01 - Are we getting the most out of combination therapy in the short-term and long-term treatment of mania?

The extensive research into the treatment of bipolar disorder over the last 20 years means that we, as clinicians, have never been in a better position to treat patients with bipolar disorder. Yet despite the availability of modern, evidence-based treatment guidelines, bipolar disorder remains an everyday treatment challenge. Newly diagnosed patients requiring treatment for the first time are not always adequately controlled with single-agent therapy and, similarly, combination therapy is also frequently necessary as maintenance treatment. But with this recognition comes the new challenge of identifying when monotherapy is not enough, which agents to combine, when and for how long? How do we know?

Joined by an internationally respected faculty, Professor Siegfried Kasper chairs a discussion to help answer some of the key questions facing clinicians today:

What response can be anticipated from recommended first-line monotherapies for acute mania?

How do we know whether the response we observe when we prescribe a first-line treatment in a manic patient is adequate?

To what extent can a partial non-response to monotherapy be improved by the addition of a second agent?

What's the benefit of maintaining combination treatment once patients are stable and how long should I continue?

Does adding an antipsychotic to a mood stabiliser increase the risk of adverse events, in the short term or in the long term?

Drawing on latest guideline recommendations, recent clinical research, case studies and their extensive clinical experience, the panel will debate these interesting questions and shed light on how we can optimize both acute and maintenance treatment in this patient group.

Although the design of maintenance studies in bipolar disorder has significantly evolved in recent years, individual study designs continue to differ in important ways, with important implications. What may appear to be small differences between study designs, such as the type of most recent episode experienced by the patients or the stabilisation criteria used in the trial, can have big implications for study outcome. It is thus becoming increasingly important to be able to evaluate the results of trials within the context of the design and determine what they mean for treatment practice. Our panel will therefore also discuss the extent to which the design of bipolar maintenance studies can influence the results achieved and share their views on what this means for treatment now, and in the future.

Are we, and more importantly our patients, getting the most out of combination therapy for bipolar mania? Come and debate the issues with the panel, share your views and see what can be achieved.

Rational polypharmacy in the bipolar affective disorders

Bipolar affective illness represents a syndrome not readily treated by single agents. Approximately 50% of patients are inadequately responsive to lithium and the majority of patients require supplemental antidepressants, antimanic, antipsychotic or hypnotic medications. These traditional adjunctive medications are associated with potential problems. Antidepressants may precipitate mania (at a rate about double that of placebo) or cause cycle acceleration. Neuroleptics may be associated with either more profound or longer depressive phases, and clearly increase the risk of tardive dyskinesia, to which bipolar patients appear particularly predisposed. Moreover, there are subgroups of patients who are known to be poorly responsive to lithium. These include patients with rapid cycling, dysphoric mania, co-morbid drug or alcohol abuse, a pattern of depression-mania-well interval (D-M-I as opposed to the M-D-I pattern), and patients without a family history of bipolar illness in first-degree relatives. There is increasing recognition that the anticonvulsants carbamazepine and valproate are effective alternatives or adjuncts to lithium in the acute and long-term treatment of bipolar illness. Ideally, one would want to assess whether patients who were unresponsive to lithium were responsive to an anticonvulsant alone prior to utilizing lithium in addition to anticonvulsant combination therapy. However, from the clinical perspective, it is often more expedient to use an anticonvulsant adjunctively to lithium to assess the efficacy of this combination and establish mood stabilization. When lithium is not discontinued, the increased morbidity during lithium withdrawal also would not occur and would not confound the evaluation of the new agent. We suggest the initial use of acute adjuncts to lithium with the anticonvulsants carbamazepine or valproate (instead of neuroleptics) so that their efficacy can be assessed in the individual's acute episode, with the likelihood of a positive response in longer-term prophylaxis. Hypnotic benzodiazepines with anticonvulsant properties, such as clonazepam or lorazepam, are often used to help to induce sleep in escalating bipolar patients, and may be useful adjuncts as well. Patients who were inadequately responsive to either carbamazepine or valproate alone may be responsive to the anticonvulsant combination. In a similar fashion, one can also utilize several mood-stabilizing drugs (lithium and an anticonvulsant such as carbamazepine or valproate) in the treatment of depressive breakthroughs, and then augment this combination (if necessary) with a catecholamine-active antidepressant such as bupropion or a serotonin-selective reuptake inhibitor (SSRI) such as fluoxetine, paroxetine, sertraline or if necessary a monoamine oxidase inhibitor (MAOI). Once the patient has responded to a combination of drugs, it becomes problematic to decide whether the last agent added was the crucial ingredient in helping the patient achieve remission or that remission might have occurred with this agent alone. A conservative approach would have merit in patients who are finally stabilized on complex polypharmacy regimens only after many years of sequential trials; in this instance, the potential risk of re-exacerbating the illness with a taper of one of the drugs in the regimen. Rational polypharmacy should thus be implemented with careful delineation of the prior course of illness (typically using life chart methodology) and targeted treatment outcomes titrated against side effects, using sequential clinical trials in individual patients who have not adequately responded to monotherapy. In this fashion, it is hoped that pharmacodynamic differences among agents can be maximized and pharmacokinetic and side effects minimized.

Use of fat-fed rats to study the metabolic and vascular sequelae of obesity and beta-adrenergic antagonism

Obesity-associated cardiovascular disease exerts profound human and monetary costs, creating a mounting need for cost-effective and relevant in vivo models of the complex metabolic and vascular interrelationships of obesity. Obesity is associated with endothelial dysfunction and inflammation. Free fatty acids (FFA), generated partly through beta-adrenergic receptor-mediated lipolysis, may impair endothelium-dependent vasodilation (EDV) by proinflammatory mechanisms. beta-Adrenergic antagonists protect against cardiovascular events by mechanisms not fully defined. We hypothesized that beta antagonists may exert beneficial effects, in part, by inhibiting lipolysis and reducing FFA. Further, we sought to evaluate the fat-fed rat as an in vivo model of obesity-induced inflammation and EDV. Control and fat-fed rats were given vehicle or beta antagonist for 28 d. Serum FFA were measured to determine the association to serum IL6, TNFalpha, and C-reactive protein and to femoral artery EDV. Compared with controls, fat-fed rats weighed more and had higher FFA, triglyceride, leptin, and insulin levels. Unexpectedly, in control and fat-fed rats, beta antagonism increased FFA, yet inflammatory cytokines were reduced and EDV was preserved. Therefore, reduction of FFA is unlikely to be the mechanism by which beta antagonists protect the endothelium. These results reflect the need for validation of ex vivo models of obesity-induced inflammation and endothelial dysfunction, concurrent with careful control of dietary fat composition and treatment duration.