The FRESH Study: Treatment of Intracranial Aneurysms with the New FRED X Flow Diverter with Antithrombotic Surface Treatment Technology-First Multicenter Experience in 161 Patients.

BACKGROUND AND PURPOSE: Flow diverters with antithrombotic coatings are increasingly used to improve the safety of flow diverter treatments of intracranial aneurysms. This study aimed to investigate the safety and short-term efficacy of the new FRED X flow diverter. MATERIALS AND METHODS: Medical charts and procedural and imaging data of a consecutive series of patients with intracranial aneurysms who were treated with the FRED X at 9 international neurovascular centers were retrospectively analyzed. RESULTS: One hundred sixty-one patients (77.6% women; mean age, 55 years) with 184 aneurysms (11.2% acutely ruptured) were included in this study. Most aneurysms were located in the anterior circulation (77.0%), most frequently at the ICA (72.7%). The FRED X was successfully implanted in all procedures. Additional coiling was performed in 29.8%. In-stent balloon angioplasty was necessary in 2.5%. The rate of major adverse events was 3.1%. Thrombotic events occurred in 7 patients (4.3%) with 4 intra- and 4 postprocedural in-stent thromboses, respectively (1 patient had both peri- and postprocedural thrombosis). Of these thrombotic events, only 2 (1.2%) led to major adverse events (ischemic strokes). Postinterventional neurologic morbidity and mortality were observed in 1.9% and 1.2%, respectively. The rate of complete aneurysm occlusion after a mean follow-up of 7.0 months was 66.0%. CONCLUSIONS: The new FRED X is a safe and feasible device for aneurysm treatment. In this retrospective multicenter study, the rate of thrombotic complications was low, and the short-term occlusion rates are satisfactory.

Optimisation of the AP abdomen projection for larger patient body thicknesses.

INTRODUCTION: This study aims to identify optimal exposure parameters, delivering the lowest radiation dose while maintaining images of diagnostic quality for the antero-posterior (AP) abdomen x-ray projection in large patients with an AP abdominal diameter of >22.3 cm. METHODOLOGY: The study was composed of two phases. In phase 1, an anthropomorphic phantom (20 cm AP abdominal diameter) was repetitively radiographed while adding 3 layers (5 cm thick each) of fat onto the phantom reaching a maximum AP abdominal diameter of 35 cm. For every 5 cm thickness, images were taken at 10 kVp (kilovoltage peak) intervals, starting from 80 kVp as the standard protocol currently in use at the local medical imaging department, to 120 kVp in combination with the use of automatic exposure control (AEC). The dose area product (DAP), milliampere-second (mAs) delivered by the AEC, and measurements to calculate the signal to noise ratio (SNR) and contrast to noise ratio (CNR) were recorded. Phase 2 included image quality evaluation of the resultant images by radiographers and radiologists through absolute visual grading analysis (VGA). The resultant VGA scores were analysed using visual grading characteristics (VGC) curves. RESULTS: The optimal kVp setting for AP abdominal diameters at: 20 cm, 25 cm and 30 cm was found to be 110 kVp increased from 80 kVp as the standard protocol (with a 56.5% decrease in DAP and 76.2% in mAs, a 54.2% decrease in DAP and 76.2% decrease in mAs and a 29.2% decrease in DAP and 59.7% decrease in mAs, respectively). The optimal kVp setting for AP abdominal diameter at 35 cm was found to be 120 kVp increased from 80 kvp as the standard protocol (with a 50.7% decrease in DAP and 73.4% decrease in mAs). All this was achieved while maintaining images of diagnostic quality. CONCLUSION: Tailoring the exposure parameters for large patients in radiography of the abdomen results in a significant reductions in DAP which correlates to lower patient doses while still maintaining diagnostic image quality. IMPLICATIONS FOR CLINICAL PRACTICE: This research study and resultant parameters may help guide clinical departments to optimise AP abdomen radiographic exposures for large patients in the clinical setting.

Thermal lability of beta galactosidase from pink salmon liver.

The effect of heat on the stability of a protein isolated from a cold-water fish was tested by following the decrease in enzymatic activity of beta galactosidase, purified from livers of Pacific pink salmon. The thermal stability is pH-dependent; it is highest at pH 4 and lowest at neutral pH, where only 30 percent of the activity remains after 10 minutes at 40 degrees C. Comparative experiments demonstrate greater thermal stability of beta galactosidase from rat liver.

Caspase-dependent and -independent cell death of Jurkat human leukemia cells induced by novel synthetic ceramide analogs.

Ceramide metabolism has emerged as a potential target for anticancer therapy. Here, the potential usefulness of two novel synthetic ceramide analogs as anti-leukemic drugs was investigated. Compounds AD2646 and AD2687 were able to dose-and time-dependently decrease the viability of Jurkat leukemic cells. This was accompanied by an accumulation of endogenous ceramide owing to perturbed ceramide metabolism. Cytotoxicity involved caspase activation but also necrotic-like features, as evidenced by phosphatidylserine externalization, membrane permeability, hypodiploidy, caspase processing and only partial protection from cell death by a pan-caspase inhibitor. Ceramide analogs also induced cell death in Jurkat mutants that are deficient in cell death signaling proteins, including FADD, caspase-8 and 10, and RIP. While overexpression of Bcl-xL did not suppress ceramide accumulation, it conferred robust protection from caspase activation and cell death. Altogether, these novel ceramide analogs are able to kill leukemic cells through distinct pathways implicating caspase activation and mitochondrial events, and represent a new group of bioactive molecules with potential applications in anticancer therapy.

Reversal of acquired resistance to doxorubicin in P388 murine leukemia cells by perhexiline maleate.

The effects of perhexiline maleate on growth and drug sensitivity were studied in the P388 murine leukemia cell line and in an anthracycline-resistant subline (P388/ADR). At noninhibitory concentrations, perhexiline maleate markedly increased the sensitivity of P388/ADR cells to doxorubicin but did not have such an effect on anthracycline-sensitive cells. The effects of perhexiline maleate on P388/ADR cells were reversible. Perhexiline maleate also increased the accumulation of another anthracycline, daunorubicin, in P388/ADR cells but did not increase its accumulation in the anthracycline-sensitive cells. Perhexiline maleate did not affect the sensitivity of either cell line to methotrexate or to 6-mercaptopurine. However, its effects on the sensitivity and on drug accumulation of vinblastine, a drug to which P388/ADR cells are cross-resistant, were similar to those observed for the anthracyclines. Although perhexiline maleate has been reported to be a calcium antagonist in other systems, our data do not suggest that this mechanism is involved in its enhancement of the sensitivity of P388/ADR cells to doxorubicin. We suggest instead that this effect might be associated with alterations of cell lipid metabolism induced by perhexiline maleate.

Rate equations and simulation curves for enzymatic reactions which utilize lipids as substrates. I. Interaction of enzymes with the monomers and micelles of soluble, amphiphilic lipids.

Theoretical aspects of the kinetics of interaction of enzymes with lipid substrates are presented. Rate equations were written and used to simulate v versus S curves for interaction of enzymes with "monomers" (i.e. a molecular solution) or micelles (aggregated form) of the "soluble", amphiphilic lipids. The rate equations were written assuming separate kinetic parameters for the interaction of the enzyme with these two forms. Although the rate equations are based on the kinetic theory of Michaelis and Menten, most of the simulated v vs. S curves were not hyperbolic. A procedure is suggested for determining the kinetic parameters with the aid of a graphic method.

Rate equations and simulation curves for enzymatic reactions which utilize lipids as substrates. II. Effect of adsorption of the substrate or enzyme on the steady-state kinetics.

Theoretical aspects of the kinetics of interaction of enzymes with lipid substrates are presented. Rate equations were written and used to simulate v versus S curves for the following cases: (a) The substrate is adsorbed onto non-catalytic sites of the enzyme or to other proteins accompanying the enzyme. (b) The enzyme is adsorbed, via non-catalytic sites to aggregated forms of the substrate. (c) The substrate is adsorbed onto an externally added protein such as albumin. Although all rate equations are based on the Michaelis-Menten kinetic theory, most of the simulated v vs. S curves were not hyperbolic and some of the v vs. E curves not linear.

Uptake and intracellular degradation of fluorescent sphingomyelin by fibroblasts from normal individuals and a patient with Niemann-Pick disease.

Sphingomyelin, labelled with a fluorescent probe, pyrene, in the fatty acyl residue was associated with fetal calf serum; approx. 80% of the sphingomyelin was found in the low- and high-density lipoproteins. This was added to the growth medium of cultured human skin fibroblasts from normal individuals and a patient with Niemann-Pick disease type A, devoid of acid sphingomyelinase activity. The fluorescent sphingomyelin was taken up by both cell types, but only the former degraded it to produce fluorescent ceramide. Differences between normal and Niemann-Pick cells in sphingomyelin content or ceramide production were observed after several hours uptake. A more pronounced difference was noted when cells were incubated for 1 day with fluorescent sphingomyelin and then for two to three days in medium devoid of this compound. Under these conditions, the fluorescence intensity of the Niemann-Pick cells remained practically constant while that of their normal counterparts was almost completely eliminated from the cells. Comparison of fluorescence intensities of these two cell types could be made directly on aqueous suspensions of whole cells or, alternatively, on their lipid extracts. For evaluation of the degradation of fluorescent sphingomyelin to ceramide within the cells, several procedures were developed for the rapid isolation of the latter compound from the total lipid extract. The results suggest that when associated with the constituents of the fetal calf serum, sphingomyelin is taken up by the cells and transported into the lysosomal compartment where it is degraded to ceramide. Use of the fluorescent derivative of sphingomyelin provided a simple and rapid procedure for following the uptake by and degradation within the cultured cells. It also permitted the establishment of differences in the rates of degradation of the fluorescent sphingomyelin by cells with a normal metabolism and others lacking sphingomyelinase (i.e., Niemann-Pick disease type A cells).

Spectrofluorometric measurements of the dispersion state of pyrenedodecanoic acid and its uptake by cultured cells and liposomes.

Pyrene dodecanoic acid (P12), a medium-chain fatty acid to which the fluorescent probe pyrene is covalently linked, showed a considerable increase in fluorescence when the probe was introduced into a hydrophobic environment. Also, when closely packed in an aggregate, an energy transfer between two adjacent molecules of pyrene occurred, resulting in a shift of the peak of the emission spectrum from 378 nm ('monomeric') to 475 nm ('excimeric'). These two respective properties were utilized for the following: (a) A spectrofluorometric measurement of the critical micellar concentration (CMC) of the pyrene fatty acid, defined as the concentration at which the 475 nm emission peak appeared as a consequence of the aggregation of P12 molecules in aqueous solution to form micelles; the CMC of P12 was found to be in the range of 1 to 2 microM. (b) The penetration of P12, from an aqueous solution or dispersion, into unilamellar phospholipid vesicles was determined by monitoring the increase of the fluorescence at 378 nm. The fluorescence increase was time-dependent and proportional to the respective concentrations of P12 or phospholipid vesicles. Substituting the neutral phosphatidylcholine with the negatively-charged phosphatidylserine vesicles resulted in a slower rate as well as lesser total uptake of P12. (c) The uptake of P12 by cells was accompanied by an increase in the monomeric fluorescence emission intensity. Using cells in suspension, this could be followed continuously in a spectrofluorometer equipped with a recorder. The uptake was found to be time-dependent and proportional to P12 concentration.

The hydrolysis of triacylglycerol and diacylglycerol by a rat brain microsomal lipase with an acidic pH optimum.

Lipase activity towards triacylglycerol and diacylglycerol was measured at pH 4.8 using a microsomal preparation from rat brain as the enzyme source. The optimal pH for the hydrolysis of triacylglycerol was 4.8, with only minor lipolytic activity in the alkaline pH range. Diacylglycerol was the major product of triacylglycerol hydrolysis, with only little monoacylglycerol being formed. When diacylglycerol was the starting substrate it was hydrolyzed at a rate 10-fold greater than triacylglycerol, and the product was monoacylglycerol. The enzyme showed positional specificity for the fatty acid moieties located at the primary positions of sn-glycerol. 1,3-Diacylglycerol was hydrolyzed at greater than twice the rate of the corresponding 1,2(2,3)-isomer.

Synthesis of trinitrophenylaminolauric acid and the use of its glyceryl esters for assaying lipase by a spectrophotometric procedure.

Trinitrophenylaminolauric acid was synthesized from omega-aminolauric acid and trinitrobenzenesulfonic acid and then condensed with glycerol to yield mono-, di- and triacylglyceryl esters of this acid. Hydrolysis of these glycerides was followed by isolation of the yellow fatty acid with the aid of one solvent extraction step and estimating its content by spectrophotometry. This procedure was used to assay the activities of lipases from hog pancreas, rat bile, microsomes of rat brain and Rhizopus arrhizus delamar.

A spectrophotometric method for determination of sphingomyelinase.

A colored derivative of sphingomyelin was synthesized and used as substrate for several sphingomyelinases. The compound is N-omega-trinitrophenyl-aminolaurylsphingosylphosphorylcholine. The rate of hydrolysis of this substrate was compared to that of bovine brain sphingomyelin, labelled with tritium in the choline moiety. The following enzyme preparations were used: homogenate-less debris of brain, assayed at pH 5.0 or 7.4; a solubilized preparation derived from rat brain lysosomes, assayed at pH 5.0 and a purified enzyme of Staphylococcus aureus. With all preparations, the rates of hydrolysis of the yellow derivative were very similar to those of the brain sphingomyelin. Extracts of skin fibroblasts of normal and Niemann-Pick patients as well as amniotic cells were also used. Again, the rates of hydrolysis of the yellow derivative practically equalled those using brain sphingomyelin.