Diagnostic accuracy of myocardial perfusion imaging with single photon emission computed tomography and positron emission tomography: a comparison with coronary angiography

Objective The aim of this study was to compare the diagnostic accuracy of myocardial perfusion imaging (MPI) by positron emission tomography (PET) with the diagnostic accuracy of MPI by single photon emission computed tomography (SPECT) in two comparable patient cohorts, using coronary angiography (CA) as the standard of reference. Methods A “SPECT-group” of 80 patients (15 female, 65 male; mean age 60 ± 9 years) and a “PET-group” of 70 patients (14 female, 56 male; mean age 57 ± 10 years) underwent a one day stress/rest examination either with attenuation-corrected ¹³N-ammonia PET or attenuation-corrected ²⁰¹TlCl SPECT or ^99mTc-hexakis-methoxy-isobutyl-isonitril (MIBI) SPECT. PET and SPECT results were semiquantitatively graded using a 6-segment heart model. All patients underwent CA, and stenoses were graded as a diameter reduction ≥50%. Results Coronary findings between both groups did not significantly differ at CA. For the SPECT-group overall sensitivity and specificity for localisation of stenoses was 77% and 84%. Respective values for the PET-group were 97% and 84%. The specificity of MPI by SPECT in the detection of ischemia was 74% and 91% for MPI by PET. The diagnostic accuracy of MPI improves when the individual coronary dominance and previous coronary revascularisations are taken into account. Conclusion MPI by ¹³N-ammonia PET is more sensitive in the detection and localisation of coronary stenoses, and more specific in the detection of ischemia than MPI by ²⁰¹TlCl/^99mMIBI SPECT.     

Accuracy of dual-source CT coronary angiography: first experience in a high pre-test probability population without heart rate control

The aim of this study was to assess the diagnostic accuracy of dual-source computed tomography (DSCT) for evaluation of coronary artery disease (CAD) in a population with extensive coronary calcifications without heart rate control. Thirty patients (24 male, 6 female, mean age 63.1±11.3 years) with a high pre-test probability of CAD underwent DSCT coronary angiography and invasive coronary angiography (ICA) within 14±9 days. No beta-blockers were administered prior to the scan. Two readers independently assessed image quality of all coronary segments with a diameter ≥1.5 mm using a four-point score (1: excellent to 4: not assessable) and qualitatively assessed significant stenoses as narrowing of the luminal diameter >50%. Causes of false-positive (FP) and false-negative (FN) ratings were assigned to calcifications or motion artifacts. ICA was considered the standard of reference. Mean body mass index was 28.3±3.9 kg/m² (range 22.4–36.3 kg/m²), mean heart rate during CT was 70.3±14.2 bpm (range 47–102 bpm), and mean Agatston score was 821±904 (range 0–3,110). Image quality was diagnostic (scores 1–3) in 98.6% (414/420) of segments (mean image quality score 1.68±0.75); six segments in three patients were considered not assessable (1.4%). DSCT correctly identified 54 of 56 significant coronary stenoses. Severe calcifications accounted for false ratings in nine segments (eight FP/one FN) and motion artifacts in two segments (one FP/one FN). Overall sensitivity, specificity, positive and negative predictive value for evaluating CAD were 96.4, 97.5, 85.7, and 99.4%, respectively. First experience indicates that DSCT coronary angiography provides high diagnostic accuracy for assessment of CAD in a high pre-test probability population with extensive coronary calcifications and without heart rate control.     

Decreased intracellular degradation and increased secretion of apo B-100 in Hep G2 cells after inhibition of cholesteryl ester synthesis

Control of apolipoprotein B (apo B) secretion in hepatocytes occurs partly at the post-translational level. The key step in this process appears to be intracellular degradation of newly synthesized apo B. The aim of this paper was to investigate the mechanisms that regulate apo B secretion by Hep G2 cells, in response to the inhibition of Acyl-CoA Acyltransferase (ACAT) by the compound Sandoz 58035 (S-58035). S-58035 (20 μM) reduced cholesteryl ester synthesis from [¹⁴C]oleate by 95%, and increased significantly, in a dose-dependent manner, (2–100 μM) apo B secretion, either in control conditions (from 78±4.3 to 126±6.1 ng apo B-100/mg cell protein/4 h) or upon stimulation of apo B secretion by oleate (from 134±4.23 to 177±4.3 ng apo B/mg cell protein/4 h). This increased secretion of newly synthesized apo B-100 was confirmed by pulse experiments and by gradient ultracentrifugation of the media. Moreover pulse-chase experiments showed that the addition of S-58035 reduced intracellular degradation of apo B-100, both in control conditions and in the presence of oleate. S-58035 (20 μM) did not affect total cellular cholesterol content, but free cholesterol increased with a concomitant decrease of cholesteryl ester (−20%). S-58035 increased cellular triglyceride mass, which was observed in basal conditions (from 12.8±1.09 to 22.7±2.7 μg TG/mg cellular protein) and also in presence of oleate (from 48±0.53 to 59±6.3 μg TG/mg cellular protein). This effect is due to a stimulation of triglyceride synthesis, as determined by incorporation of [³H]glycerol into cellular triglycerides. From these data we conclude that, under our experimental conditions, triglyceride synthesis and/or availability is likely to control intracellular degradation of apo B.     

The histone deacetylase inhibitor ITF2357 has anti-leukemic activity in vitro and in vivo and inhibits IL-6 and VEGF production by stromal cells.

We have investigated the activity of ITF2357, a novel hydroxamate histone deacetylase inhibitor, on multiple myeloma (MM) and acute myelogenous leukemia (AML) cells in vitro and in vivo. ITF2357 induced apoptosis in 8/9 MM and 6/7 AML cell lines, as well as 4/4 MM and 18/20 AML freshly isolated cases, with a mean IC(50) of 0.2 microM. ITF2357 activated the intrinsic apoptotic pathway, upregulated p21 and downmodulated Bcl-2 and Mcl-1. The drug induced hyperacetylation of histone H3, H4 and tubulin. When studied in more physiological conditions, ITF2357 was still strongly cytotoxic for the interleukin-6 (IL-6)-dependent MM cell line CMA-03, or for AML samples maximally stimulated by co-culture on mesenchymal stromal cells (MSCs), but not for the MSCs themselves. Interestingly, ITF2357 inhibited the production of IL-6, vascular endothelial growth factor (VEGF) and interferon-gamma by MSCs by 80-95%. Finally, the drug significantly prolonged survival of severe combined immunodeficient mice inoculated with the AML-PS in vivo passaged cell line already at the 10 mg/kg oral dose. These data demonstrate that ITF2357 has potent anti-neoplastic activity in vitro and in vivo through direct induction of leukemic cell apoptosis. Furthermore, the drug inhibits production of growth and angiogenic factors by bone marrow stromal cells, in particular IL-6 and VEGF.     

A unified definition of clinical resistance/intolerance to hydroxyurea in essential thrombocythemia: results of a consensus process by an international working group.

A widely accepted definition of resistance or intolerance to hydroxyurea (HU) in patients with essential thrombocythemia (ET) is lacking. An international working group (WG) was convened to develop a consensus formulation of clinically significant criteria for defining resistance/intolerance to HU in ET. To this aim, an analytic hierarchy process (AHP), a multiple-attribute decision-making technique, was used. The steps consisted of selecting the candidate criteria for defining resistance/intolerance; identifying the motivations that could influence the preference of the WG for any individual criterion; comparing the candidate criteria in a pair-wise manner; and grading them according their ability to fulfill the motivations. Every step in the model was derived by questionnaires or group discussion. The WG proposed that the definition of resistance/intolerance should require the fulfillment of at least one of the following criteria: platelet count greater than 600,000/micro l after 3 months of at least 2 g/day of HU (2.5 g/day in patients with a body weight over 80 kg); platelet count greater than 400,000/micro l and WBC less than 2500/micro l or Hb less than 10 g/dl at any dose of HU; presence of leg ulcers or other unacceptable muco-cutaneous manifestations at any dose of HU; HU-related fever.     

Retroperitoneal leiomyosarcoma: clinical case

The Authors have reported a case of retroperitoneal leiomyosarcoma. The retroperitoneal localization is quite unusual and early diagnosis is difficult. Only surgery operation and radio-chemotherapy can improve the prognosis. Tumor size is the major prognostic factor.     

Fluoxetine dose and outcome in antidepressant drug trials

OBJECTIVE: One potential for bias in the evaluation of a new drug is the dose used, both for the new compound and for the reference drug. The present study compared fluoxetine dose and outcome in trials in which fluoxetine was the experimental drug with trials in which it was the comparator. METHODS: Systematic review of randomised controlled trials comparing fluoxetine with any other antidepressant in depressive patients. Studies were allocated to one of the following two groups: group 1 = fluoxetine was the experimental drug; group 2 = fluoxetine was the control drug. Trials were located by searching the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register and the Cochrane Controlled Trials Register. RESULTS: The systematic search yielded 103 randomised trials. Studies in which fluoxetine was the experimental drug adopted a higher dose regimen than group-2 studies. In the efficacy analysis, the weighted rate of fluoxetine responders was 70.1% (confidence interval 67.4%, 72.8%) in group-1 studies and 57.9% (57.2%, 58.7%) in group-2 studies. In the effectiveness analysis, the weighted rate of fluoxetine responders was 56.4% (55.3%, 57.6%) in group-1 studies and 51.9% (51.2%, 52.7%) in group-2 studies. The weighted rate of fluoxetine dropouts was higher in group-1 studies. CONCLUSION:. Fluoxetine dose and outcome changed according to whether this drug was used as a new compound or as a reference.     

Modulation of gastric emptying and gastrointestinal transit in rats through intestinal cannabinoid CB(1) receptors

We studied the delay in gastric emptying and gastrointestinal transit induced by the cannabinoid receptor agonists (+)-WIN 55,212-2 (R(+)-[2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazin-yl]-(1-naphthalenyl)methanone mesylate) and CP 55,940 ((-)-cis-3[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl) cyclohexanol), as prevented by the selective cannabinoid CB(1)-receptor antagonist SR141716 ((N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methylpyrazole-3-carboxamide)) in rats after systemic or central drug administration. Oral SR141716 showed comparable potency (ID(50) range 1.0-3.9 mg/kg) in antagonizing gastric emptying and gastrointestinal transit delay by (+)-WIN 55,212-2 or CP 55,940. Gastric emptying and gastrointestinal transit delay after intracerebroventricular (i.c.v.) (+)-WIN 55,212-2 was prevented by oral or i.c.v. SR141716, but i.c.v. SR141716 did not significantly reduce the effect of i.p. (+)-WIN 55,212-2. Pertussis toxin prevented the delaying action of i.c.v. (+)-WIN 55,212-2 on both gastric emptying and gastrointestinal transit, but had no effect on (+)-WIN 55,212-2 i.p. These findings are consistent with a primary role of peripheral cannabinoid CB(1) receptor mechanisms in gastrointestinal transit delay by specific agonists.